References

Botly LC, De Rosa E (2008) Cholinergic deafferentation of the neocortex with 192 IgG-Saporin impairs feature binding in rats. Neuroscience 2008 Abstracts 418.2. Society for Neuroscience, Washington, DC.

Summary: The binding problem refers to the fundamental challenge of the central nervous system to integrate sensory information registered by distinct brain regions to form a unified neural representation of a stimulus. While the cognitive mechanisms and functional neuroanatomy of feature binding have been well examined by the human cognitive literature, the neurochemistry of feature binding remains unknown. We contend that acetylcholine (ACh) is critical for feature binding given this neuromodulator’s presumed role in modulating attention, and the well-established importance of attention to feature binding. Using systemic pharmacology in rats, we have previously established a critical role for ACh in feature binding at encoding, but have yet to identify the target brain regions cholinergic input must reach for successful feature binding to occur. Given the recognized importance of the frontal and parietal cortices to attentional processing, we hypothesized that cholinergic deafferentation of the neocortex would impair feature binding in a similar manner to that of systemic cholinergic blockade. To test this hypothesis, rats received bilateral 192 IgG-Saporin lesions of the nucleus basalis magnocellularis (NBM) of the basal forebrain. Relative to sham-lesioned rats, NBM-lesioned rats were significantly impaired at acquiring a crossmodal Feature-Conjunction (FC) task, while their ability to retrieve the FC task and to acquire a crossmodal Feature-Singleton (FS) task remained intact. These findings provide further support for our cholinergic attentional hypothesis of feature binding and reveal the importance of neocortical cholinergic input from the basal forebrain to the feature binding encoding process.

Related Products: 192-IgG-SAP (Cat. #IT-01)

Jeong D, Hwang Y, Chang J (2008) The effect of electrical stimulation in the rats for dementia animal model. Neuroscience 2008 Abstracts 340.11/M2. Society for Neuroscience, Washington, DC.

Summary: Forebrain Cholinergic neurons in the nucleus basalis meynert (NBM) project primarily to the neocortex, and those in the medial septum project to the hippocampus and make a role in memory function. A case study was reported that electrical stimulation of the hypothalamus improves hippocampus dependent memory function. The hypothesis of this study is that electrical stimulation of NBM would induce memory enhancement by effect on neocortex and/or hippocampus. Animal models were induced by selective immunolesion of cholinergic neurons. The cholinergic immunotoxin 192 IgG-saporin was injected in lateral ventricle. 192 IgG-saporin injected rats were compared with Dulbecco’s phosphate bufferd saline (DPBS) injected rats. Neurological deficit and functional outcome were determined by immuohistochemistry using anti-choline acetyl transferase antibody and Morris water maze behavioral test. DBS electrode was implanted in NBM and Stimulation parameters are selected from animal stimulation test. Extent of the cholinergic lesion was showed in the basal forebrain complex region at 192 IgG-saporin injected rats. 192 IgG-saporin injected rats were severely impaired in the probe test of the water maze test. We observe that NBM stimulation induced memory enhancement in dementia models through the behavioral test. Therefore, our animal DBS system could be a useful instrument for investigation of dementia.

Related Products: 192-IgG-SAP (Cat. #IT-01)

Croxson PL, Browning PGF, Gaffan D, Baxter MG (2008) Cholinergic depletion of the inferior temporal cortex interferes with recovery from episodic memory deficits. Neuroscience 2008 Abstracts 292.7/SS20. Society for Neuroscience, Washington, DC.

Summary: Cholinergic innervation of the temporal lobe has been suggested to have a role in episodic memory, a function which is also disrupted by lesions or disconnections of the medial temporal lobe circuit. Acetylcholine may be necessary for the specific function of some brain regions. Alternatively, it may be necessary for cortical plasticity and remodeling in those conditions in which the animal has to adapt following new task demands or injury. To investigate the role of cholinergic projections to inferotemporal cortex in episodic memory, and how loss of these projections might interact with damage to other brain structures necessary for normal memory function, we trained monkeys preoperatively on object-in-place scene discrimination problems until they could rapidly learn many problems within a testing session. Because learning occurs rapidly, mostly in a single trial, and depends on the presentation of discrimination problems in unique background scenes, this task models key features of human episodic memory. For the first stage of the experiment, the monkeys then received either a fornix transection or mammillary body ablation, both of which are known to impair learning in this task. All of the monkeys were impaired at scene learning after fornix or mammillary body lesions compared to their preoperative performance, consistent with previous results. In the second stage of the experiment, the monkeys underwent a second surgery in which we used the immunotoxin ME20.4-saporin to selectively deplete cholinergic inputs to the inferotemporal cortex. We then re-tested the monkeys on scene learning, and they were no more impaired than they were after their first surgery. This result is in striking contrast to an earlier finding by our laboratory that the effect of fornix transection is greatly exacerbated by prior depletion of acetylcholine from inferotemporal cortex (Browning et al. 2008, in press). The key difference between these two experiments is the order in which the lesions were placed: cholinergic depletion of inferotemporal cortex before fornix transection results in severe amnesia, whereas severe amnesia does not occur if the lesions are sustained in the opposite order. This finding suggests that monkeys require acetylcholine in inferotemporal cortex in order to adjust to the effects of a fornix lesion on episodic memory. This is consistent with a role for cholinergic input to neocortex in cortical plasticity and remodelling, rather than a specific role in certain brain functions such as episodic memory.

Related Products: ME20.4-SAP (Cat. #IT-15)

Baxter MG, Kyriazis DA, Croxson PL (2008) Cholinergic depletion of prefrontal cortex impairs acquisition of the delayed response task in rhesus monkeys. Neuroscience 2008 Abstracts 292.9/SS22. Society for Neuroscience, Washington, DC.

Summary: The involvement of corticopetal cholinergic projections in cognition remains difficult to define. Some investigators have suggested that normal cortical function requires an intact cholinergic input, whereas others emphasize a selective role of acetylcholine in attentional function or plasticity. Because of the anatomical and functional homology of human and macaque cortical structures, studies of the effects of selective ablation of cholinergic projections to cortical regions in the macaque would clarify the functions for which these projections are essential. We have tested 3 male rhesus monkeys with multiple bilateral injections of the immunotoxin ME20.4-saporin into lateral and orbital prefrontal cortex on a suite of cognitive tasks dependent on the integrity of orbital and ventrolateral prefrontal cortex, on which they were unimpaired. These tasks included new object-in-place scene learning, strategy implementation, and reinforcer devaluation. To determine the involvement of acetylcholine in dorsolateral prefrontal cortex function, we then trained these monkeys on the spatial delayed response task (Goldman, 1970; Bachevalier and Mishkin, 1986) in a manual testing apparatus. In this task the monkey watches as an experimenter places a small food reward in one of two wells of a test tray and then covers both wells with identical gray plaques. After a brief delay (1-5 sec) during which an opaque screen is interposed between the monkey and experimenter, the monkey is allowed to obtain the reward by displacing the plaque covering the well that was baited by the experimenter. Thus, the monkey must maintain the baited location (left or right) in memory during the brief delay interval in order to choose correctly. Performance of this task is devastated by ablation of dorsolateral prefrontal cortex. The monkeys with cholinergic depletion of lateral and orbital prefrontal cortex were also unable to learn the task to criterion, which four unoperated control monkeys learned readily. This finding suggests that acetylcholine, although not critical for functions of ventrolateral and orbital prefrontal cortex, is essential for dorsolateral prefrontal cortex function. An alternative explanation, which we are currently investigating, is that acetylcholine is necessary for the prefrontal cortex to adapt to the different task demands of delayed response, relative to the tests of discrimination learning with which these monkeys had extensive experience. This would be consistent with a role for cholinergic input to neocortex in cortical plasticity and remodeling.

Related Products: ME20.4-SAP (Cat. #IT-15)

Gulino R, Gulisano M (2008) Sonic hedgehog expression and glial reaction after neurotoxic lesion of adult mice spinal cord by Cholera Toxin-B Saporin. Neuroscience 2008 Abstracts 124.14/B14. Society for Neuroscience, Washington, DC.

Summary: The spinal cord (SC) has ever been considered non-neurogenic because no neurons seem to be generated in the intact SC and only very few recent articles have reported spontaneous generation of new neurons after lesion. Conversely, many studies have demonstrated the occurrence of glial reaction after either mechanical or selective neurotoxic lesion. Sonic hedgehog (Shh) is a member of hedgehog family of secreted glycoproteins, which stimulate cell proliferation as well as neuron and oligodendrocyte differentiation during either development and adulthood. Few data are available about its role in the adult SC after injury. In this study, we used Cholera toxin-B saporin (CTB-sap), a retrogradely transported, ribosome-inactivating toxin, to induce a mild neurotoxic depletion of motoneurons within lumbar SC and to subsequently study the expression levels of Shh and the possible cell proliferation and differentiation within the depleted SC of young adult mice. After an injection of CTB-sap into the gastrocnemius muscle, we found a 30% depletion of lumbar SC motoneurons, and a comparable decrease of ChAT expression levels in the lumbar SC, one week after lesion. Moreover, we found a significant down-regulation of Shh expression, which significantly correlate with ChAT decrease. Both proteins recovered to near normal levels of expression at one month after lesion. The expression of ChAT also correlate with the performance of mice on a grid walk test. So, the observed spontaneous recovery of locomotion was associated with the spontaneous recovery of ChAT and Shh expression. Moreover, we observed a cell proliferation within the depleted SC parenchyma, which was associated with a visible increase of GFAP-positive astrocytes in the same area. Colocalization studies showed that the majority of these proliferating cells are active astrocytes. We hypothesized that Shh expression could have a role in both SC plasticity and the observed glial reaction after neurotoxic lesion. The restoration of normal levels of Shh during the first days after lesion could be a way to partially inhibit glial reaction and to improve functional recovery.

Related Products: CTB-SAP (Cat. #IT-14)

Edelmayer RM, Vanderah TW, Majuta L, Fioravanti B, De Felice M, Chichorro JG, Ossipov MH, King T,Lai J, Kori SH, Nelsen AC, Cannon KE, Heinricher MM, Porreca F (2008) A brainstem generator for cutaneous allodynia associated with migraine headache. Neuroscience 2008 Abstracts 171.15/LL16. Society for Neuroscience, Washington, DC.

Summary: Migraine patients often demonstrate cutaneous allodynia that begins unilaterally and intracranially and spreads, via unknown mechanisms, to contralateral and extracranial body regions. As cutaneous allodynia likely reflects the development of central sensitization, we hypothesized that descending facilitatory influences from the rostral ventromedial medulla (RVM) might underlie the generalized expression of this phenomenon. We employed a modified model of application of inflammatory mediators (IM) to the dura of unanesthetized animals and explored the possible requirement of a brainstem site for expression of generalized cutaneous allodynia. Rats were surgically implanted with two cannulas, one of which permitted the application of IM to the surface of the dura and the other for administration of compounds to the RVM, 7 days after surgery. Tactile withdrawal thresholds of the peri-ocular region of the face as well as the hindpaws were tested pre-surgery, post-surgery, and up to 6 hr after application of IM. Bupivacaine or YM022 (CCK2 receptor antagonist) were administered to the RVM at various times after IM. In some studies dermorphin-saporin was administered as a single microinjection to elicit a cytotoxic effect on presumed pain facilitation cells in the RVM; these rats were tested with IM after a further 28 days. Recordings of RVM “ON” and “OFF” cell activity were also performed in separate groups of naïve animals prior to, and after, IM application to the dura. Dural IM produced robust facial and hindpaw allodynia which peaked after approximately 3 hr and recovered to baseline thresholds by approximately 6 hr. RVM bupivacaine, YMO22, or cytotoxic destruction of pain facilitation cells had no effects on sensory thresholds alone, but prevented or significantly attenuated the expression of IM-induced cutaneous allodynia. In addition, IM applied to the dura produced a sustained increase in the discharge of RVM ON cells while transiently inhibiting OFF cells. Facial and hindpaw allodynia associated with dural stimulation may be a useful surrogate of migraine-associated pain which may be exploited mechanistically for the development of novel therapeutic strategies. The data demonstrate the requirement of descending facilitation from the RVM for the expression of cranial and extracranial cutaneous hypersensitivity and offer direct evidence of brainstem involvement in cutaneous allodynia associated with headache pain.

Related Products: CCK-SAP (Cat. #IT-31)

Sikandar S, Dickenson AH (2008) Lumbosacral-bulbo-spinal loop relayed by RVM on-cells regulates visceral nociception and modulates inhibitory effects of pregabalin and ondansetron. Neuroscience 2008 Abstracts 269.4/GG19. Society for Neuroscience, Washington, DC.

Summary: Descending controls from brainstem nuclei including the rostral ventromedial medulla (RVM) have been shown to play an important role in visceral pain, and compounds modulating serotonergic receptor activity and compounds targeting the α2δ subunit of voltage-gated calcium channels have demonstrated clinical efficacy in providing symptomatic relief in patients with visceral hyperalgesia. We investigated the role of RVM on-cells and a serotonergic lumbosacral-bulbo-spinal loop in visceral hyperalgesia and examined the antihyperalgesic effects of ondansetron and pregabalin in modifying visceral pain responses to colorectal distension (CRD) in rats. An in vivo model of visceral pain was established involving CRD and a reliable EMG recording protocol for measuring activity in the external oblique muscle following CRD for quantifying evoked visceromotor responses (VMR) in Sprague-Dawley rats. Changes in VMR evoked by CRD in a range of 10-80 mmHg were recorded following administration of ondansetron (50 μg/kg i.t.) and pregabalin (30 mg/kg s.c.) in naïve rats and rats pretreated with 0.25% intracolonic mustard oil (MO) to induce colonic hyperalgesia. Moreover, RVM on-cells were selectively ablated with injection of the neurotoxin saporin conjugated to the μ-receptor agonist dermorphin (DermSAP) using stereotaxic techniques. Twenty-eight days post-injection, the VMR were compared between naïve, SAP and Derm-SAP rats in control conditions and following intracolonic MO. CRD produced graded VMR responses that were facilitated by intracolonic MO. Both ondansetron and pregabalin were shown to effectively reduce evoked VMR to CRD in naïve rats and MO pretreated rats by antagonizing spinal 5-HT3 receptors and by binding to the α2δ subunit of voltage-gated calcium channels, respectively. Moreover, DermSAP pretreatment was shown to reduce overall evoked VMR, and the antihyperalgesic efficacies of ondansetron and pregabalin were also shown to be modified by the loss of on-cells in DermSAP rats. Furthermore, we verified immunohistochemically RVM on-cell ablation in DermSAP rats and quantified RVM 5-HT cell intensity between naïve, SAP and DermSAP rats. This study illustrates the role of 5-HT3-mediated descending facilitatory controls in visceral pain as well as providing evidence for the antihyperalgesic efficacy of the second generation α2δ ligand pregabalin in the CRD model. Moreover, evidence is provided for a facilitatory serotonergic lumbosacral-bulbo-spinal loop relayed by RVM on-cells that is evoked by CRD and modulates efficacies of pregabalin and ondansetron.

Related Products: Dermorphin-SAP / MOR-SAP (Cat. #IT-12)

Emanuel AJ, Dinh TT, Ritter S (2008) The ablation of hindbrain catecholamine neurons innervating medial hypothalamic nuclei abolishes glucoprivic feeding, but spares the orexigenic response to ghrelin. Neuroscience 2008 Abstracts 85.2/RR15. Society for Neuroscience, Washington, DC.

Summary: Ghrelin is an orexigenic peptide synthesized in the stomach and secreted during fasting. Receptors for ghrelin are present in the brain and direct injection of ghrelin into the brain evokes feeding. Nevertheless, Y. Date et. al. (2002) have claimed that gastric vagal afferent neurons are the major pathway conveying ghrelin’s signals for starvation and growth hormone secretion to the brain. Furthermore, this group (Date et. al., 2006), has reported that noradrenergic neurons transmit ghrelin’s orexigenic signals from the hindbrain to the hypothalamus. The latter assertion was based on the loss of ghrelin-induced feeding in rats injected into the arcuate nucleus (ARC) with anti-dopamine beta hydroxylase (DBH) conjugated to saporin (DSAP), which retrogradely destroys DBH-containing neurons. We previously showed that DSAP microinjection either into the hypothalamic paraventricular nucleus (PVH) or ARC abolished glucoprivic feeding. Since glucoregulatory responses include alterations of both feeding and growth hormone secretion, we reasoned that the same catecholamine neurons sensitive to glucoprivation may contribute to these responses following ghrelin. To investigate this issue further, we microinjected DSAP (n=7) or unconjugated saporin (SAP control, n=7) bilaterally into the PVH of Sprague-Dawley rats (approximately 400 g BW). Three weeks later, daytime tests for feeding responses to 2-deoxyglucose (2DG, 200 mg/kg, 4-hr test) and ghrelin (15 µg/kg, i.p., 2-hr test) were conducted. As expected, DSAP abolished 2DG-induced feeding. However, the response to ghrelin was not abolished in DSAP treated rats. In fact, feeding in response to ghrelin was significantly enhanced in DSAP-treated rats, compared to the control SAP group (p<0.05). These results confirm our prior findings relative to the role of catecholamine projections in glucoprivic responses, but they contradict the results previously reported by Date et. al. The difference between our injection sites (we injected DSAP into the PVH, and Date injected into the ARC) is not likely to account for the different results since injections of DSAP into either site eliminate DBH terminals throughout the medial hypothalamus and appear to lesion the same population of catecholamine neurons. Therefore, until more detailed analysis is conducted, we conclude that hindbrain catecholamine neurons are required for glucoprivic but not ghrelin-induced feeding.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

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.

Related Products: 192-IgG-SAP (Cat. #IT-01), GAT1-SAP (Cat. #IT-32)

Rouleau C, Curiel M, Weber W, Smale R, Kurtzberg L, Mascarello J, Berger C, Wallar G, Bagley R, Honma N, Hasegawa K, Ishida I, Kataoka S, Thurberg BL, Mehraein K, Horten B, Miller G, Teicher BA (2008) Endosialin protein expression and therapeutic target potential in human solid tumors: sarcoma versus carcinoma. Clin Cancer Res 14:7223-7236. doi: 10.1158/1078-0432.CCR-08-0499

Summary: Endosialin is an antigen expressed in many human cancer cell lines. As part of a wide-ranging study investigating clinical specimens, cell culture, and animal models, this group used Hum-ZAP (Cat. #IT-22) combined with a humanized anti-endosialin antibody in cell proliferation assays. Mouse IgG-SAP (Cat. #IT-18) was used as a control. The anti-endosialin antibody and Hum-ZAP were incubated together in equimolar concentrations then applied to cells in culture. Various cancers, including synovial sarcoma, fibrosarcoma, and osteosarcoma among others, were found to express endosialin.

Related Products: Hum-ZAP (Cat. #IT-22), Mouse IgG-SAP (Cat. #IT-18)