29 entries found for : it-32
Maejima Y, Yokota S, Horita S, Shimomura K (2019) The undeveloped properties of GABA neurons in the ventral tegmental area promote energy intake for growth in juvenile rats. Sci Rep 9(1):11848. doi: 10.1038/s41598-019-48336-5
Objective: To determine the underlying mechanisms that induce high energy intake (EI) per body weight (BW).
Summary: Undeveloped properties of VTA GABA neurons in juvenile rats can promote higher EI regardless of high or less palatable feeding, and contribute to growth promotion.
Usage: GAT1-SAP or control, Rabbit IgG-SAP, was bilaterally injected (0.025 μg/0.5 μl) into the VTA in eight-week-old adult rats.Related Products: GAT1-SAP (Cat. #IT-32), Rabbit IgG-SAP (Cat. #IT-35)
Solari N, Hangya B (2018) Cholinergic modulation of spatial learning, memory and navigation. Eur J Neurosci 48:2199-2230. doi: 10.1111/ejn.14089
Kruashvili L, Dashniani M, Beselia G, Chkhikvishvili N (2018) Expression of NR2B subunit of the NMDA receptor and spatial long-term memory in medial septal lesioned rats. FENS 2018 Abstracts F038. Federation of European Neuroscience Societies, Berlin, Germany.
Summary: The present study was designed to investigate the effect of selective immunolesions of cholinergic and GABA- ergic SH projection neurons (using 192 IgG-saporin and GAT-1 saporin, respectively) on spatial memory assessed in water maze and the N-methyl-D-aspartate (NMDA) receptor GluN2B subunit expression in the rat hippocampus. Animals were tested in a standard Morris water maze. We found that immunolesion of medial septal cholinergic neurons did not affect spatial learning as exhibited by a decreased latency to find the hidden platform across the eight training trials. In contrast, rats with immunolesions of medial septal GABAergic neurons did not show a decreased latency across training trials in water maze. Trained control rats spent significantly longer than chance (15 s) performances such as swimming time in test sector (where the hidden platform was located). Moreover, they spent significantly longer in test sector than in the opposite sector, confirming the establishment of long-term memory. In contrast, the preference for test sector was abolished in medial septal immunolesioned rats. Because Saporin treated rats learned the location of the hidden platform during training, the results suggest that saporin treated rats could not remember the training a day later. We found that the expression level of NR2B subunit of NMDA receptor in the hippocampus was decreased significantly in the GAT-1 treated group compared with the control and saporin treated groups. In conclusion, our findings suggest that immunolesion of medial septal GABAergic neurons can interrupt hippocampus-dependent spatial learning, possibly through modulation of NMDA receptor subunit expression in the hippocampus.
Rusadze K, Sakandelidze R, Chighladze M (2018) Effects of lesions of medial septal area on spatial short-term memory. FENS 2018 Abstracts F044. Federation of European Neuroscience Societies, Berlin, Germany.
Summary: In the present study electrolytic and the immunotoxins (192 IgG saporin and GAT1-SAP) lesions of medial septal area (MS) were used to investigate the importance of cholinergic and GABAergic MS neurons in spatial working memory using spatial alternation task. In our experiments electrolytic lesions destroyed on average 69% of the intact MS. Examination of the AChE stained sections showed that after injections of 192 IgG saporin into the MS, animals exhibited significantly less AChE staining in MS as compared to sections obtained from control animals. Intraseptal GAT1-SAP preferentially reduced GABAergic neurons as compared to cholinergic neurons in the MS. The results of present study indicate that spatial short-term memory is affected only by electrolytic but not 192 IgG saporin or GAT1-SAP lesions. The behavioral testing showed that 192 IgG saporin treated rats, relative to control rats, had a significantly lower level in the number of arms entered during the testing session. However, the groups did not differ in the level of alternation behavior. GAT1-SAP lesioned rats showed that the percent alternation scores and the number of arms that the rat entered in the maze were not significantly different from control rats.
Beselia G, Dashniani M, Burjanadze M, Solomonia R, Kruashvili L, Chkhikvishvili N (2017) Modulation of GluN2B subunit-containing NMDA receptors expression and spatial long-term memory in medial septal immunolesioned rats. Neuroscience 2017 Abstracts 428.01 / UU39. Society for Neuroscience, Washington, DC.
Summary: The hippocampus is important in the formation of spatial memory in both humans and animals. The N-methyl-D-aspartate (NMDA) type of glutamate receptors in the hippocampus has been reported to be essential for spatial learning and memory as well as for the induction of synaptic plasticity. Evidence accumulated from recent studies suggest that GluN2A and GluN2B subunit-containing NMDA-Rs preferentially contribute to the induction of hippocampal LTP and LTD. Using a Morris water maze (MWM) task, the LTP- blocking GluN2A antagonist had no signiﬁcant eﬀect on any aspect of performance, whereas the LTD-blocking GluN2B antagonist impaired spatial memory consolidation.1The present study was designed to investigate the eﬀect of selective immunolesions of cholinergic and GABA-ergic1septohippocampal projection neurons [using 192 IgG-saporin (SAP) or GAT1-1 saporin (GAT), respectively] on spatial memory assessed in MWM and NMDA receptor GluN2B subunit expression in the rat hippocampus. We used MWM training protocol with eight training trials. One day after training, probe test with the platform removed was performed to examine long-term spatial memory retrieval. We found that immunolesions of medial septal cholinergic or GABAergic neurons did not aﬀect spatial learning as exhibited by a decreased latency to ﬁnd the hidden platform across the eight training trials. Trained control and SAP treated rats spent signiﬁcantly longer than chance (15 s) performances such as swimming time in test sector (where the hidden platform was1located). Moreover, they spent signiﬁcantly longer in test sector than the opposite sector, conﬁrming the establishment of long-1term memory. In contrast, the preference for test sector was abolished in medial septal GAT treated rats. Because GAT treated rats learned the location of the hidden platform during training, the result suggest that GAT level of NR2B subunit of NMDA receptor in the hippocampus was decreased signiﬁcantly in the GAT treated group compared with the control and SAP treated groups.1In conclusion, our ﬁndings suggest that immunolesion of medial septal GABAergic neurons can interrupt hippocampus dependent1spatial memory, possible through modulation of NMDA receptor subunit expression in the hippocampus. Moreover, our ﬁnding that selective lesions of medial septal GABAergic neurons affect probe-test performance but not spatial learning, suggests that septohippocampal GABAergic projections are involved speciﬁcally in the consolidation or retrieval, but not in the acquisition of long- term memory.
Burjanadze M, Mataradze S, Rusadze K, Chkhikvishvili N, Dashniani M (2015) Selective lesion of GABA-ergic neurons in the medial septum by GAT1-saporin impairs spatial learning in a water-maze. Georgian Med News 240:59-64.
Summary: The authors investigated the role of GABAergic neurons in the medial septum on spatial learning using a Morris water maze test. Rats received bilateral injections totaling 162 ng of GAT-1-SAP (Cat. #IT-32) into the medial septum. Saporin (Cat. #PR-01) was used as a control. The lesioned animals displayed significant deficits during the water maze task, indicating that GABAergic neurons in the medial septum are intrinsic to organization of spatial map-driven behavior.
Dashniani M, Kruashvili L, Rusadze K, Matatradze S, Beselia G (2015) Effects of immunotoxic and electrolytic lesions of medial septal area on spatial short-term memory in rats. Georgian Med News 239:98-103.
Summary: In this work the authors investigated how essential septohippocampal projections are in a spatial working memory model. Rats received bilateral injections of 192-IgG-SAP (Cat. #IT-01, 600 ng total) or GAT-1-SAP (Cat. #IT-32, 195 ng total) into the medial septum. Saporin (Cat. #PR-01) was used as a control.
Kruashvili L, Mepharishvili M, Dashniani M, Burjanadze M, Demurishvili M (2014) Spatial long-term memory and modulation of NMDA receptor subunit expression in medial septal immunolesioned rats. Neuroscience 2014 Abstracts 463.19. Society for Neuroscience, Washington, DC.
Summary: The present study was designed to investigate the effect of selective immunolesions of cholinergic and GABA-ergic SH projection neurons (using 192 IgG-saporin and GAT-1 saporin, respectively) on spatial memory assessed in water maze and the N-methyl-D-aspartate (NMDA) receptor GluN2B subunit expression in the rat hippocampus. We used water maze training protocol with eight training trials. One day after training, probe test with the platform removed was performed to examine long-term spatial memory retrieval. We found that immunolesion of medial septal cholinergic neurons did not affect spatial learning as exhibited by a decreased latency to find the hidden platform across the eight training trials. In contrast, rats with immunolesions of medial septal GABAergic neurons did not show a decreased latency across training trials in water maze. Trained control rats spent significantly longer than chance (15 s) performances such as swimming time in test sector (where the hidden platform was located). Moreover, they spent significantly longer in test sector than in the opposite sector, confirming the establishment of long-term memory. In contrast, the preference for test sector was abolished in medial septal immunolesioned rats. Because Saporin treated rats learned the location of the hidden platform during training, the results suggest that saporin treated rats could not remember the training a day later. We found that the expression level of NR2B subunit of NMDA receptor in the hippocampus was decreased significantly in the GAT-1 treated group compared with the control and saporin treated groups. In conclusion, our findings suggest that immunolesion of medial septal GABAergic neurons can interrupt hippocampus[[unable to display character: ‐]]dependent spatial learning, possibly through modulation of NMDA receptor subunit expression in the hippocampus. Moreover, our finding that selective lesions of medial septal cholinergic neurons affects probe-test performance but not spatial learning, suggests that septohippocampal cholinergic projections are involved specifically in the consolidation or retrieval, but not in the acquisition of long-term spatial memory.
Kozikowski CT, Wolfe EL, Yanev PG, Burk JA (2014) Interactions between noncholinergic basal forebrain neurons and muscarinic receptors in attentional processing. Neuroscience 2014 Abstracts 263.16. Society for Neuroscience, Washington, DC.
Summary: Numerous studies have provided evidence that basal forebrain corticopetal cholinergic neurons are critical for normal attentional performance. However, the role of noncholinergic basal forebrain neurons in attention has not been well-characterized. Moreover, evidence regarding interactions between cholinergic receptor activity and noncholinergic basal forebrain neurons remains scarce. In the present experiment, rats (n=15) were trained in a two-lever sustained attention task that required to discriminate between brief illumination of a centrally located panel light (500, 100, 25 ms) from trials when the light was not illuminated. After reaching criterion performance, rats received infusions into the basal forebrain of saline (n=7) or the immunotoxin, GAT1-saporin (n=8), to lesion noncholinergic neurons. After re-establishing performance after surgery, all rats received systemic administration of the muscarinic receptor antagonist, scopolamine (0, 0.05, 0.20 mg/kg, ip). When attentional testing resumed after surgical recovery, lesioned animals’ task performance did not significantly differ from sham-lesioned animals. However, following the highest dose of scopolamine, lesioned animals exhibited a larger decline in signal detection accuracy compared to sham-lesioned animals. Additionally, lesioned animals’ omission rate was higher during injection sessions compared to sham-lesioned animals. These results suggest that noncholinergic basal forebrain neurons are not necessary for performance in a well-trained attention task. However, loss of these neurons renders animals’ attentional performance more vulnerable to decreased cholinergic system stimulation. Finally, the lesion-induced increase in omissions may reflect a role for noncholinergic basal forebrain neurons in processes beyond attention.
Related Products: GAT1-SAP (Cat. #IT-32)
Roland JJ, Stewart AL, Janke KL, Gielow MR, Kostek JA, Savage LM, Servatius RJ, Pang KC (2014) Medial septum-diagonal band of Broca (MSDB) GABAergic regulation of hippocampal acetylcholine efflux is dependent on cognitive demands. J Neurosci 34(2):506-514. doi: 10.1523/JNEUROSCI.2352-13.2014
Summary: GABAergic and cholinergic neurons in the medial septum-diagonal band of Broca (MSDB) are both involved with spatial memory. In order to better understand the relationship between these two neuronal populations the authors administered 552.5 ng of GAT-1-SAP (Cat. #IT-32) to the MSDB of rats in several injections. Using a combination of behavioral assays and in vivo microdialysis it was shown that GAT-1-SAP lesions impaired hippocampal acetylcholine efflux as well as performance in the non-matching to position with delay test. The data indicate that GABAergic MSDB neurons are important during high memory load conditions.
Related Products: GAT1-SAP (Cat. #IT-32)
Baxter MG, Bucci DJ (2013) Selective immunotoxic lesions of basal forebrain cholinergic neurons: twenty years of research and new directions. Behav Neurosci 127(5):611-618 . doi: 10.1037/a0033781
Summary: This review covers twenty years of basal forebrain cholinergic lesioning. The initial use of 192-IgG-SAP (Cat. #IT-01) is discussed, as well as other immunotoxins such as GAT-1-SAP (Cat. #IT-32) and OX7-SAP (Cat. #IT-02). The findings generated by the use of 192-IgG-SAP and how those data have helped forward the understanding of how the cholinergic system functions in the basal forebrain are detailed. The authors also discuss new directions in the field.
Roland J, Janke K, Servatius R, Pang K (2014) GABAergic neurons in the medial septum-diagonal band of Broca (MSDB) are important for acquisition of the classically conditioned eyeblink response. Brain Struct Funct 219:1231-1237. doi: 10.1007/s00429-013-0560-4
Summary: The medial septum and vertical limb of the diagonal band of Broca (MSDB) are both important for learning and memory. There are strong connections between these two areas, and damage to one or the other can result in differing dysfunctions. The authors investigated how damage to GABAergic neurons in the MSDB affect acquisition of delay classical conditioning of the eyeblink response (CCER). Rats received 162 ng of GAT-1-SAP (Cat. #IT-32) into the medial septum and 130 ng of GAT-1-SAP into each diagonal band. Treated animals displayed impaired initial acquisition of the eyeblink response, indicating that MSDB GABAergic neurons modulate delay CCER – a task that is not dependent on the hippocampus.
Related Products: GAT1-SAP (Cat. #IT-32)
Koppen JR, Stuebing SS, Winter SS, Cheatwood JL, Wallace DG (2012) Infusion of GAT1-Saporin into the medial septum spares mnemonic function and impairs self-movement cue processing. Neuroscience 2012 Abstracts 394.25. Society for Neuroscience, New Orleans, LA.
Summary: Spatial orientation depends on multiple neural systems processing environmental and self-movement cues. Previous research has demonstrated a relationship between cholinergic function in the medial septum and processing of self-movement cues. The medial septum also sends GABAergic projections to the hippocampus that synapse on interneurons, thereby producing a strong dis-inhibitory effect on hippocampal pyramidal neurons. Initial studies using non-selective lesion techniques have supported the involvement of this system in spatial orientation; however, the development of an immunotoxin (i.e., GAT1-Saporin) that selectively targets GABAergic neurons, allows for a novel technique in which to study this relationship. The current study examined the effect of infusing GAT1-Saporin or saline into the medial septum on performance during multiple spatial tasks. Environmental and self-movement cue processing was evaluated using the food hoarding paradigm, whereas mnemonic function was evaluated using several water maze tasks. Although GAT1-Saporin spared performance on water maze tasks, impaired performance was observed when rats were restricted to using self-movement cues (i.e., testing under dark conditions) during food hoarding. The current study adds to the growing literature that supports a role for components of the septohippocampal system in self-movement cue processing during spatial navigation.
Related Products: GAT1-SAP (Cat. #IT-32)
Koppen JR, Winter SS, Stuebing SL, Cheatwood JL, Wallace DG (2013) Infusion of GAT1-saporin into the medial septum/vertical limb of the diagonal band disrupts self-movement cue processing and spares mnemonic function. Brain Struct Funct 218(5):1099-1114. doi: 10.1007/s00429-012-0449-7
Summary: Both mnemonic and spatial processing are adversely affected by dementia due to Alzheimer's disease. There is evidence to support the involvement of cholinergic systems in this deficit. In this work the authors examined how GABAergic neurons in the septohippocampus contribute to these cognitive functions. Rats received a total of 350 ng of GAT-1-SAP (Cat. #IT-32) infused into the medial septum-diagonal band of Broca. Although lesioned animals performed normally in tasks involving spatial cues, food hoarding was affected indicating that self-movement cue processing was interfered with by the loss of these GABAergic neurons.
Related Products: GAT1-SAP (Cat. #IT-32)
Stewart AL, Roland JJ, Servatius RJ, Pang K (2011) Role of the medial septal-diagonal band nucleus in working memory: Effects of cholinergic or GABAergic lesions on memory demand and interference. Neuroscience 2011 Abstracts 513.09. Society for Neuroscience, Washington, DC.
Summary: The medial septum and diagonal band of Broca (MSDB), a major source of afferents to the hippocampal formation, is critical for learning and memory. The primary cells comprising the septohippocampal systems are cholinergic, GABAergic and glutamatergic. Selective damage of cholinergic MSDB neurons results in mild to no impairment of spatial working memory tasks, suggesting that non-cholinergic MSDB projections are important in learning and memory. Recently, we demonstrated that GABAergic MSDB lesions impair a delayed match to position task (DNMTP) with errors suggesting enhanced proactive interference. The current study assesses the effect of manipulating the intertrial interval (ITI) and retention interval (RI) on DNMTP performance in normal rats and those with cholinergic or GABAergic MSDB damage. In addition, activation of MSDB neurons on the last day of training will be assessed. Male Sprague Dawley rats receive sham, 192-IgG saporin (192-Sap) or GAT1-saporin (GAT1-Sap) administration into the MSDB before training on a DNMTP task using a T-maze. On the sample phase of each trial, rats are forced to one arm for reinforcement. Following an RI, a choice phase allows the rats to choose from both arms. Rats are reinforced for choosing the arm not entered during the sample phase. Following the choice phase, an ITI occurs before the sample phase of the next trial. Rats are trained one session per day, 12 trials per session, and 10 sessions. In a 2 x 2 experimental design, each rat is trained on either a 0 or 60s RI and a 0 or 60s ITI. Conditions with a long RI (60 s) are designed to tax working memory, whereas conditions with a similar RI and ITI are designed to increase interference. Immunocytochemistry for c-Fos is used to assess activation of cholinergic or GABAergic MSDB neurons following the last training session. As expected, our preliminary results show that sham rats performed better on 0 s than 60 s RI (0 s = 78% correct vs 60 s = 57%, both ITI’s pooled). Analysis of the 0 s RI demonstrates that performance in conditions with different RI and ITI was better than when RI and ITI were similar (0 s RI/60 s ITI = 74% vs 0 s RI/0 s ITI = 67%). Further analysis of the 60 s RI was difficult due to the near chance performance. Rats treated with either intraseptal 192-Sap or GAT1-Sap were impaired on the 0 s RI/60s ITI condition (Sham: 85%; 192-Sap: 65%; GAT1-Sap: 72%). However, only the 192-Sap rats were impaired in the 0 s RI/0 s ITI condition (Sham: 71%; 192-Sap: 62%; GAT1-Sap: 69%). Anatomical studies are currently underway. The results of this study will further elucidate the role of MSDB neurons in two aspects of working memory: memory demand and interference.
Roland JJ, Stewart AL, Savage LM, Servatius RJ, Pang KCH (2011) Reduced hippocampal acetylcholine efflux after medial septal-diagonal band (MSDB) GABAergic lesion is associated with impaired working memory: behavioral and neurochemical effects of physostigmine. Neuroscience 2011 Abstracts 513.10. Society for Neuroscience, Washington, DC.
Summary: The medial septum provides cholinergic innervation of the hippocampus and changes in hippocampal acetylcholine (ACh) have been tied to memory; deficits and enhancements in memory are correlated with decreases or increases of ACh, respectively. Damage of GABAergic MSDB neurons impaired spatial working memory in a delayed non-match to position task with a 30-s retention interval (DNMTP). Interestingly, lesions reduced maze activated hippocampal ACh efflux, but did not alter basal hippocampal ACh efflux. The current study has two aims. First, is performance impaired and ACh efflux reduced in a non-match to position task (NMTP) with a 0-s retention interval following GABAergic MSDB damage? Second, is performance on DNMTP improved by enhancing hippocampal ACh efflux? Male Sprague-Dawley rats received intraseptal PBS or GAT1-saporin (to damage GABAergic neurons) and a ventral hippocampal microdialysis cannula to assess ACh efflux. In Exp. 1, rats were trained on NMTP for 10 days and received microdialysis on either day 2 (early) or day 9 (late). GAT1-saporin rats were not behaviorally impaired and hippocampal ACh efflux was similar in both treatment groups. These results suggest that performance with a short retention interval (NMTP) is more independent of MSDB influences than training with a long retention interval (DNMTP). Exp. 2 was designed to determine whether the reduced ACh efflux is a critical factor in impaired DNMTP performance in rats with GABAergic MSDB damage. In Exp. 2, all rats will receive 10 day of DNMTP training. On days 8 and 9, rats will be administered (i.c.v.) either saline or the acetylcholinesterase inhibitor, physostigmine (5μg/μl). The effects of physostigmine on behavioral performance and hippocampal ACh efflux will be determined. We predict that physostigmine will increase ACh efflux but not improve behavior, suggesting that hippocampal ACh is not important for DNMTP performance. However, support that both MSDB cholinergic and GABAergic neurons are important for DNMTP performance would be seen if physostigmine increases ACh efflux and enhances DNMTP performance. In summary, damage of MSDB GABAergic neurons modulates hippocampal ACh efflux during performance of a working memory task. Whether hippocampal ACh release plays a critical role in impaired working memory will be answered by these studies.
Related Products: GAT1-SAP (Cat. #IT-32)
Sinha SP, Roland JJ, Servatius RJ, Pang KCH (2011) The role of medial septal/diagonal band GABAergic neurons in proactive interference: Effects of selective immunotoxic lesions in latent inhibition. Neuroscience 2011 Abstracts 199.22. Society for Neuroscience, Washington, DC.
Summary: The medial septum/diagonal band (MSDB) is a critical structure for learning and memory, yet the functional contributions of its individual neuronal populations (including cholinergic, GABAergic, glutamatergic and peptidergic cells) are still being characterized. Recent studies have implicated a contributing role for the GABAergic MSDB neuronal population, as selective immunotoxic GABAergic lesions of the MSDB (with GAT1-saporin) produce behavioral impairments in spatial and instrumental tasks. Compared to intact controls, rats with GABAergic MSDB lesions are impaired in learning new spatial locations in a delayed match to position procedure and also exhibit a slower rate of extinguishing a previously acquired avoidance response - behaviors that are consistent with an exacerbation of proactive interference. To further establish the role of these neurons in proactive interference, this study examined the effects of selective GABAergic MSDB lesions in latent inhibition (LI) of the classically conditioned eyeblink response. LI in delay eyeblink conditioning is a phenomenon in which pre-exposure to the conditioned stimulus (CS) interferes with the subjects’ ability to subsequently associate the CS with an unconditioned stimulus (US), resulting in slower acquisition of the conditioned response (CR). We hypothesized that if damage of GABAergic MSDB neurons increases proactive interference, then rats with selective lesions of these neurons would show facilitated LI. Male Sprague-Dawley rats (n=18) were administered either phosphate-buffered saline or GAT1-saporin via intracranial injection into the MSDB. After 7-10 days of recovery, electrodes were implanted into the upper eyelids of the rats for delivery of US and EMG recording. Conditioning began after another 5-7 days of recovery, with Day 1 consisting of 30 minutes of acclimation to the conditioning context. Day 2 began with either 30 presentations of the CS (82dB, 500ms white noise, 25 - 35s ITI) or context pre-exposure of equal duration, followed immediately by 100 paired CS-US trials (82 dB, 500ms white noise co-terminating with a 10V, 10ms square-wave stimulus). In preliminary results, intraseptal GAT1-saporin did not alter CR acquisition in context pre-exposed rats. Rats with GABAergic MSDB lesions continued to exhibit latent inhibition. These preliminary results do not support the idea that damage of GABAergic MSDB neurons increase proactive interference of the classically conditioned eyeblink response. Future studies will examine whether manipulations of the number of CS pre-exposures would facilitate LI in rats with GABAergic MSDB lesions.
Related Products: GAT1-SAP (Cat. #IT-32)
Radley JJ, Sawchenko PE (2011) A common substrate for prefrontal and hippocampal inhibition of the neuroendocrine stress response. J Neurosci 31(26):9683-95. doi: 10.1523/JNEUROSCI.6040-10.2011
Summary: In order to better understand how response to emotional stress is regulated, the authors injected 114 ng of GAT-1-SAP (Cat. #IT-32) into each side of the anterior bed nucleus of the stria terminalis. Mouse IgG-SAP (Cat. #IT-18) was used as a control. The results suggest that medial prefrontal cortex and hippocampal formation influences on stress regulation use the same access to modulate emotional stress rather than having parallel networks.
Koppen JR, Winter SS, Cheatwood JL, Wallace DG (2010) Role of the septohippocampal GABAergic system in spatial orientation. Neuroscience 2010 Abstracts 806.16/KKK21. Society for Neuroscience, San Diego, CA.
Summary: Spatial orientation depends on the integrity of multiple neural systems. For example, during the progression of Alzheimer’s Disease, degeneration of the basal forebrain is associated with cognitive impairments including episodes of wandering. The medial septum projects both cholinergic and GABAergic fibers into the hippocampus. Research and therapies have typically focused on enhancing function of the cholinergic component; however, the GABAergic component has also been shown to contribute to hippocampal function. Previous attempts to characterize the role of the GABAergic system in spatial orientation involved non-selective lesion techniques in combination with the water maze task have failed to characterize the nature of the deficit mediating the impaired performance. Development of GAT1-Saporin immunotoxin provides a novel tool to selectively destroy GABAergic neurons in the medial septum. The current study examined the effects of injecting GAT1-Saporin or saline (sham lesion) into the medial septum on spatial orientation using the food-hoarding paradigm. The food-hoarding paradigm involves training rats to search for food pellets on a large circular table and carrying the food pellet directly to a visible refuge. Three probes dissociate the use of environmental and self-movement cues: 1) Hidden probe involved placing the refuge below the surface of the table, limiting rats to use distal environmental or self-movement cues to locate the refuge; 2) Dark Probe involved using the hidden refuge with the room lights off, limiting rats to use self-movement cues to locate the refuge; 3) New probe involved placing the hidden refuge on the opposite side of table, placing environmental and self-movement cues in conflict. Both sham and GAT1-Saporin rats were accurate in returning to the refuge during the Hidden probe. Only sham rats were accurate in carrying food to the refuge during the Dark probe. During the New probe, both groups initially carried the food pellet to the former refuge location. Although sham rats consistently carried the food pellet to the new refuge location after their initial error, GAT1-Saporin rats continued to perseverate to the former refuge location. The current study demonstrates a role for the septohippocampal GABAergic system in spatial orientation related to processing self-movement cues.
Related Products: GAT1-SAP (Cat. #IT-32)
Gielow M, Roland J, Servatius, RJ Pang KCH (2010) Do GAT1-saporin lesions of the medial septum damage GABAergic afferents to the medial septum?. Neuroscience 2010 Abstracts 811.3/LLL66. Society for Neuroscience, San Diego, CA.
Summary: 192-IgG saporin is an antibody directed to the p75 receptor conjugated to the ribosomal-inactivating compound saporin. 192-IgG saporin has been widely used to selectively ablate cholinergic cells of the basal forebrain. Cholinergic lesions are typically made by injections of 192-IgG saporin at the soma in basal forebrain nuclei. However, 192-IgG saporin is also effective in damaging specific cholinergic projections by administration of the toxin in the axon terminal region. Recently, GAT1-saporin has been developed as a tool to selectively damage cells expressing the GABA transporter GAT1. GAT1-saporin combines an antibody to the GABA transporter GAT1 with saporin. GAT1 transporters are primarily localized to neurons and GAT1-saporin has been shown to selectively damage GABAergic neurons in the BNST and medial septum. Given the similarity to 192-IgG saporin, a major question is whether GAT1-saporin is effective in damaging GABAergic afferents to the area of administration. Our previous studies found that GAT1-saporin administered to the medial septum / diagonal band of Broca (MSDB) damages GABAergic septohippocampal neurons and impaired performance on delayed match to position tasks. While it seems likely that damage of GABAergic MSDB neurons is responsible for these behavioral impairments, one cannot rule out the possibility that destruction of GABAergic afferents to the MSDB may also contribute. Therefore, the present study was undertaken to determine whether GAT1-saporin lesions of the MSDB damage the GABAergic hippocamposeptal projection. Male Sprague Dawley rats received both fluorogold and either GAT1-saporin or vehicle in medial septum. Immunocytochemistry for choline acetyltransferase and parvalbumin confirmed the extent of the lesion. The majority of hippocamposeptal GABAergic neurons contain the neuropeptide somatostatin. Quantification of double-labeled hippocampal fluorogold-positive cell bodies with anti-somatostatin immunofluorescence was performed using unbiased stereology. Preliminary data suggest that GABAergic hippocamposeptal neurons are intact. These results will be important in understanding the damage produced by GAT1-saporin.
Related Products: GAT1-SAP (Cat. #IT-32)
Roland JJ, Janke KL, Savage LM, Servatius RJ, Pang KCH (2010) Damage of GABAergic neurons in the medial septum-diagonal band (MSDB) reduces behaviorally-activated hippocampal acetylcholine efflux and impairs spatial working memory. Neuroscience 2010 Abstracts 611.13/MMM64. Society for Neuroscience, San Diego, CA.
Summary: The septohippocampal pathway is mostly composed of cholinergic and GABAergic projections and has an established role in learning, memory and disorders of cognition. Most studies have focused on the role of the cholinergic system in learning, memory and disorders of cognition. Although MSDB cholinergic lesions do not result in learning impairments, changes in hippocampal acetylcholine (ACh) levels have been tied to memory functions where deficits or enhancements in memory were correlated with hippocampal ACh decreases or increases, respectively. The activity of MSDB cholinergic neurons is greatly influenced by GABAergic afferents, including those from GABAergic neurons within the MSDB. Recently, we’ve demonstrated that toxins that preferentially damage MSDB GABAergic neurons impair delayed match to position tasks, but not spatial reference memory. Interpretation of these results needs to take into account the fact that a MSDB GABAergic lesion would influence both septohippocampal cholinergic and GABAergic transmission. The current study examined the effect of MSDB GABAergic lesions on spontaneous alternation (Experiment 1) and a non-matching to position task (NMTP; Experiment 2) while concurrently using in vivo microdialysis to measure hippocampal ACh efflux. Adult male Sprague-Dawley rats received vehicle (PBS) or GABAergic (GAT-1 saporin) MSDB lesion and a hippocampal microdialysis cannula. In Experiment 1, treatment groups did not differ in terms of activity, alternation rates, or baseline and maze-activated ACh efflux. In Experiment 2, hippocampal ACh efflux was measured at two time points (early and late) across the acquisition of a delayed NMTP task. Overall, GAT1-saporin treated rats had lower accuracy scores across 10 days of maze training compared to the vehicle treated rats. Basal ACh release in the hippocampus was similar in vehicle and GAT1-saporin rats. During the two microdialysis sampling points, both groups of rats displayed significant increases in ACh efflux while performing the task. However, behaviorally activated ACh efflux was reduced in GABA-lesioned animals compared to vehicle treated rats. The results demonstrate that MSDB GABAergic lesions do not alter basal hippocampal ACh efflux, but can reduce ACh efflux when challenged cognitively. Future studies will attempt to determine whether reduced ACh efflux is due to damage of MSDB GABAergic neurons or a result of impaired working memory performance.
Related Products: GAT1-SAP (Cat. #IT-32)
Pang KCH, Jiao X, Sinha S, Beck KD, Servatius RJ (2011) Damage of GABAergic neurons in the medial septum impairs spatial working memory and extinction of active avoidance: Effects on proactive interference. Hippocampus 21(8):835-846. doi: 10.1002/hipo.20799
Summary: Recent work implicates the medial septum (MS) and diagonal band (DB) in the control of proactive interference -- forgetting older information when learning new information. Rats received GAT1-SAP (Cat. #IT-32) injections into the MS and the DB (162.5 ng and 130 ng respectively, the DB injections were bilateral). The results parallel other studies using different toxins, reinforcing the indications that GABAergic MSDB neurons are an integral part of proactive interference control.
Janke KL, Fazelinik S, Roland JJ, Servatius RJ, Servatius RJ, Servatius RJ, Pang K (2009) Role of the medial septum on navigational strategy and shifting between strategies: Effects of selective cholinergic and GABAergic lesions. Neuroscience 2009 Abstracts 283.5/EE134. Society for Neuroscience, Chicago, IL.
Summary: Cholinergic and GABAergic neurons are major components of the septohippocampal pathway, and comparisons between the two neuronal populations are important for understanding the function of medial septum-vertical limb of the diagonal band (MSDB). Recently, we have been investigating the importance of MSDB neurons in cognitive flexibility. Cognitive flexibility is commonly examined in reversal of stimulus-reward associations and attention set shifting. The present studies examine whether selective lesions of cholinergic or GABAergic MSDB neurons impair shifting between egocentric and allocentric navigation strategies. Sprague Dawley rats were administered saline, GAT1-saporin or 192-IgG saporin into the MSDB to produce no damage, selective GABAergic damage or selective cholinergic damage, respectively. Lesion verification will be performed using immunocytochemistry at the end of the studies. In a plus maze, rats started in one of two arms opposite each other (i.e., north and south arms) randomized across trials. On any single trial, the arm opposite the starting arm was blocked forming a T-maze. Rats have a choice of entering one of the remaining 2 arms (east or west arms) for food reinforcement. During the acquisition phase of the first study, rats were reinforced to enter a particular arm (east or west: allocentric response) regardless of their starting location. After they reached criteria (10 consecutive correct choices), the goal location was either reversed (east to west) or shifted to an egocentric response strategy (left or right turn). Animals that received either GAT-1-saporin (.26 ug/ul) or 192-IgG saporin (.217ug/ul) lesion reached criteria faster than saline treated rats. No significant effects of either lesion were observed on spatial reversal or strategy shifts. However, qualitative assessment of the damage suggests that GAT1-saporin may have produced an incomplete lesion. Therefore, a second study using GAT1-saporin at .325 ug/ul was conducted. For this study, half of the rats were trained on an egocentric strategy and the other rats are reinforced for an allocentric response. When rats reached criteria, half of each group was trained in a reversal learning or strategy shift. Preliminary data show that rats treated with GAT1-saporin or saline learned the initial egocentric or allocentric strategy at a similar rate. However, animals were faster to reach criteria in the allocentric condition than the egocentric condition. Reversal learning and strategy shifting in the second study is currently being assessed. The results of this study will provide important insight into the role of the MSDB in learning and cognitive flexibility.
Roland JJ, Janke KL, Gluck MA, Beck KD, Pang KCH, Servatius RJ (2009) Selective cholinergic and GABAergic lesions of the medial septum slows acquisition of the classically conditioned eyeblink response in rats. Neuroscience 2009 Abstracts 283.6/EE135. Society for Neuroscience, Chicago, IL.
Summary: Both human and animal studies have demonstrated that the hippocampus is not essential for the acquisition of delay eyeblink conditioning. However, nonselective medial septal damage, in both rabbits and humans, impaired acquisition of delayed eyeblink conditioning, as well as latent inhibition of eyeblink conditioning. The medial septum provides a major cholinergic and GABAergic afferent projection to the hippocampus, and the effects of medial septal damage is widely believed to occur through its connections to the hippocampus. Cholinergic muscarinic antagonists impaired delay eyeblink conditioning when administered systemically or directly into the hippocampus. Computational models also predicted the lack of effects on delay conditioning or latent inhibition of eyeblink conditioning caused by interference of the cholinergic septohippocampal system Recent studies have suggested that the GABAergic septohippocampal system may be a major site of action for scopolamine. Therefore, the current study examined the effect of selective cholinergic or GABAergic medial septal lesions on the classically conditioned eyeblink response. Adult male Sprague-Dawley rats received either a sham, cholinergic (192-IgG saporin) or GABAergic (GAT1-saporin) lesion in the MS/DB. Two weeks later, all animals were implanted with stimulating and recording electrodes in the periorbital muscle. Following recovery, all animals received three consecutive days of delay eyeblink conditioning. Each daily session consisted of 100 paired CS-US (conditional stimulus - unconditioned stimulus) trials with an average intertrial interval (ITI) of 30 seconds. The CS was a 500ms tone which co-terminated with the US, a 10ms, 10V periorbital stimulation. Our preliminary results shows that both cholinergic and GABAergic lesions impaired acquisition of delayed eyeblink conditioning, as compared to the sham-lesioned group. However, after three days of training all three treatment groups reached the same asymptotic performance. Future studies will assess the effects of combined cholinergic and GABAergic lesions and the effects of these septal lesions on latent inhibition of the conditioned eyeblink response.
Radley JJ, Gosselink KL, Sawchenko PE (2009) A discrete GABAergic relay mediates medial prefrontal cortical inhibition of the neuroendocrine stress response. J Neurosci 29:7330-7340. doi: 10.1523/JNEUROSCI.5924-08.2009
Summary: GABAergic neurons have been implicated in the negative regulation of the hypothalamic-pituitary-adrenal axis (HPA). In order to clarify GABAergic input to the paraventricular hypothalamic nucleus the authors injected 0.23 µg of GAT1-SAP (Cat. #IT-32) into the anterior bed nucleus of the stria terminalis. Both unilateral and bilateral injections were used. Rabbit IgG-SAP (Cat. #IT-35) was used as a control. The data indicate that the GABAergic neuronal population functions as proximate mediator of HPA-inhibitory limbic influences.
Pang K, Janke K, Servatius RJ (2008) Role of medial septum-diagonal band of Broca neurons in cognitive flexibility. Neuroscience 2008 Abstracts 89.20/SS37. Society for Neuroscience, Washington, DC.
Summary: Cholinergic and GABAergic neurons are major components of the septohippocampal pathway, and comparisons between the two neuronal populations are important for understanding the function of medial septum and vertical limb of the diagonal band (MSDB). Recently, we have been investigating the importance of MSDB neurons in cognitive flexibility. Cognitive flexibility is commonly examined in procedures that require reversal of stimulus-reward associations and those that require shifts in attention set, involving switching attention to different stimulus dimensions. Our recent studies demonstrated that selective damage of GABAergic but not cholinergic MSDB neurons impaired spatial reversal. The present study will determine whether selective lesions of cholinergic or GABAergic MSDB neurons impairs shifting of attentional set. Sprague Dawley rats will be administered saline, GAT1-saporin or 192-IgG saporin into the MSDB to produce no damage, selective GABAergic damage or selective cholinergic damage, respectively. Verification of the lesions will be performed using immunocytochemistry at the end of the study. The behavioral procedure will occur in a plus maze. Rats will start in one of two arms opposite each other (i.e., north and south arms) randomized across trials. On any single trial, the arm opposite the starting arm will be blocked forming a T-maze. Rats will have a choice of entering one of the remaining 2 arms (east or west arms) for food reinforcement. Half of the rats will be reinforced to make an egocentric response (left or right turn) and the other rats will be reinforced to go to a particular arm (east or west; allocentric response) regardless of starting location. After reaching criterion (10 consecutive correct choices), the goal location will be reversed (i.e., left turn to right turn or east to west arm) or shifted to a different dimension (i.e., left turn to east arm or west arm to right turn). It is expected that rats treated with GAT1-saporin, but not 192-saporin, will be impaired on the reversal procedure, similar to previous studies. Impairments in shifting attention set would suggest a global impairment in cognitive flexibility. However, an impairment in the reversal procedure but not shifting of attention set would be similar to recently described deficits in the nucleus basalis magnocellularis using ibotenic acid and 192-IgG saporin lesions (Tait and Brown, Behav Brain Res. 187:100, 2008). The results of this study will provide important insight into the role of the MSDB in learning, attention and cognitive flexibility.
Pang KCH, Jiao X, Servatius RJ (2008) Featured Article: Role of medial septal GABAergic neurons in learning and extinction: Effects of the novel GABA immunotoxin GAT1-SAP. Targeting Trends 9(1)
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Pang K, Sinha SP, Jiao X, Servatius RJ (2007) Understanding the role of non-cholinergic medial septal neurons in learning and memory: Implications for disease- and aging-related impairments. Neuroscience 2007 Abstracts 932.22/WW17. Society for Neuroscience, San Diego, CA.
Summary: The medial septum-diagonal band of Broca (MS) has an important function in learning and memory. Furthermore, degeneration of the MS may contribute to cognitive impairments associated with Alzheimer’s disease and normal aging. Because the MS contains several types of neurons, the neuronal population(s) involved in learning and memory has been actively investigated. Animal studies have mainly focused on the cholinergic neurons that project to the hippocampus. Although complete lesions of the MS or fimbria-fornix transaction leads to spatial memory impairments, selective damage of cholinergic MS neurons produces no or a mild impairment in spatial memory, suggesting an important role of non-cholinergic neurons. Most of these non-cholinergic neurons are GABAergic. Previously, we used low concentrations of kainic acid to examine the importance of non-cholinergic MS neurons in spatial memory. However, a more selective toxin for GABAergic neurons would facilitate research, as it has done for the cholinergic system. In the present study, we use a new GABAergic immunotoxin that combines an antibody to the GABA transporter GAT1 with saporin. GAT1-saporin was administered into the medial septum of male Sprague Dawley rats. Our preliminary results show that GABAergic septohippocampal neurons as assessed by parvalbumin-immunoreactivity were virtually eliminated, while cholinergic neurons were spared in the medial septum. Current work is focused on further characterizing the cell populations affected by GAT1-saporin. Preliminary behavioral results demonstrate that GABA MS lesions did not impair spatial reference memory in the initial acquisition of a water maze task. However, a deficit was observed in reversal learning. Further testing in a procedure where the escape platform moves to a new location every day showed that rats treated with GAT1-saporin were mildly impaired in within-session learning of the new platform location. These preliminary results demonstrate that intraseptal GAT1-saporin is effective in eliminating at least some populations of GABAergic neurons in the MS. Furthermore, the preliminary behavioral results are consistent with our previous results demonstrating that damage of non-cholinergic MS neurons produces a very specific impairment on reversal learning. In summary, GAT1-saporin may be a useful tool to examine the function of GABA MS neurons in learning and memory and their contribution to cognitive impairments in disease and aging.
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McAuley J, Pang K (2007) Effects of NBM lesions on selective attention in an interval timing task. Neuroscience 2007 Abstracts 742.9. Society for Neuroscience, San Diego, CA.
Summary: Divided and sustained attention are impaired by damage to the nucleus basalis magnocellularis (NBM), which provides cholinergic and GABAergic input to the neocortex. The present study was performed to further investigate the role of the NBM in attention using a selective attention version of the peak-interval timing procedure. Male Fisher 344 rats were initially trained using a peak interval procedure to time a light stimulus, delivering reward for the first lever press after 12 s. Selective attention was then tested in distracter sessions where random tone bursts and house light flashes were presented on some trials, but not others. These distracter sessions were interleaved with non-distracter sessions that were identical to initial peak-interval training. Preliminary results in normal young rats show that peak times on un-reinforced probe trials with distraction were lengthened as compared to probe trials without distraction in the same session. Moreover, peak times on non-distracter probe trials were similar between distracter and non-distracter sessions. In these preliminary studies, the observed overestimation of time during selective attention testing was transient, supporting the view that attention modulates the rate of an internal clock. Current studies aim to determine the influence of selective cholinergic or GABAergic NBM lesions in this selective attention task.
Related Products: GAT1-SAP (Cat. #IT-32)