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Effects of a dual hypocretin receptor antagonist on sleep and wakefulness in rats.
Schwartz MD, Dittrich L, Fisher SP, Lincoln W, Liu H, Miller MA, Warrier DR, Wilk AJ, Morairty SR, Kilduff TS (2012) Effects of a dual hypocretin receptor antagonist on sleep and wakefulness in rats. Neuroscience 2012 Abstracts 799.23. Society for Neuroscience, New Orleans, LA.
Summary: Benzodiazepine receptor agonists promote sleep by activating GABAA receptors, leading to generalized reduction in cortical activity. They are widely used as hypnotic medications, but have side effects including risk for tolerance and/or dependence, as well as cognitive impairment while under their influence. The excitatory hypocretin (HCRT) neuropeptides promote wakefulness by activating multiple subcortical wake-promoting neurotransmitter systems which, in turn, project to and regulate cortical activity. Blocking HCRT signaling should therefore promote sleep by acting specifically on subcortical brain areas regulating sleep and wake without adversely impacting cortical function. Here, we assessed the ability of the dual HCRT receptor antagonist almorexant (ALM) to promote sleep in rats following ablation of a major sleep-wake regulatory region, the cholinergic basal forebrain (BF). We predicted that ALM would be less effective at inducing sleep in BF-lesioned rats compared to neurologically-intact rats, whereas benzodiazepine-based compounds should be equally as effective in lesioned and intact rats. Male rats received bilateral stereotaxic injections of saline or the selective cholinergic neurotoxin192-IgG-saporin (SAP) directed at the BF and were implanted with telemetry for recording sleep EEG. Following recovery, animals were given increasing doses of ALM, the GABA-A receptor agonist zolpidem (ZOL), or vehicle. Spontaneous sleep/wake regulation and homeostatic recovery from sleep deprivation was also assessed. At baseline, NREM sleep in the dark (active) phase was reduced in SAP rats compared to intact rats; SAP rats also exhibited decreased NREM recovery sleep following 6 h sleep deprivation in the dark phase. Sleep in the light (rest) phase was unaffected by SAP. Analysis of ALM and ZOL administration in these animals is currently in progress.
Related Products: 192-IgG-SAP (Cat. #IT-01)
Positive allosteric modulation of 4 2* nicotinic acetylcholine receptors augments the amplitudes of prefrontal nicotine-evoked glutamatergic transients.
Grupe M, Paolone G, Jensen AA, Nielsen KS, Christensen JK, Grunnet M, Sarter M (2012) Positive allosteric modulation of 4 2* nicotinic acetylcholine receptors augments the amplitudes of prefrontal nicotine-evoked glutamatergic transients. Neuroscience 2012 Abstracts 696.15. Society for Neuroscience, New Orleans, LA.
Summary: α4β2* nicotinic acetylcholine receptors (nAChR) are a promising target for cognition enhancement. These receptors have been demonstrated to mediate the modulatory effects of the tonic component of cholinergic neurotransmission on fast prefrontal glutamatergic-cholinergic interactions. Specifically, α4β2* nAChR are expressed by thalamic glutamatergic afferents and amplify cue-evoked glutamatergic release events, thereby initiating a chain of neuronal events required for the detection of cues in attention tasks (Hasselmo & Sarter, 2011). In this study we investigated the effect of NS9283, a potent and selective positive allosteric modulator of low-sensitivity α4β2 nAChR (Timmermann et al., 2012), on nicotine-evoked glutamatergic release events in the mPFC of anaesthetized rats. Glutamatergic transients were recorded using amperometric measures of currents generated by the oxidation of glutamate and, subsequently, peroxide, on Platinum electrodes equipped with immobilized glutamate oxidase (see Parikh et al., 2010). Nicotine was pressure-ejected (0.040-2 nmol in 40-100 nL, respectively) into the vicinity of the recording electrode situated in the thalamic input layer of the prelimbic cortex. Systemic (i.p.) administration of NS9283 (3.0 mg/kg; administered 30 min prior to nicotine) enhanced the amplitude of glutamatergic transients evoked by the lowest dose of nicotine (40 pmol) by 72%. The modulator did not increase the efficacy of nicotine. Local pressure-ejections of NS9283 (400 pmol in 40 nL) per se were capable of evoking glutamatergic release events, presumably reflecting modulation of the effects of endogenous acetylcholine at these nAChRs. Accordingly, 192 IgG saporin-induced removal of cholinergic projections to the recording region abolished NS9283-evoked glutamatergic transients. Collectively, this evidence substantiates the identification of NS9283 as a positive modulator of nAChRs and its potency in vivo to modulate evoked glutamatergic release events. These results are consistent with the hypothesis that such compounds facilitate cue detection processes and thereby enhance attentional performance. Supported by NIH grant MH080332 and The Ministry of Science, Innovation and Higher Education, Denmark, PhD grant 10-084289.
Related Products: 192-IgG-SAP (Cat. #IT-01)
The effects of basal forebrain cholinergic neuron of recognition tests.
Lee J, Jeong D, Chang J (2012) The effects of basal forebrain cholinergic neuron of recognition tests. Neuroscience 2012 Abstracts 345.10. Society for Neuroscience, New Orleans, LA.
Summary: The cholinergic neurons of the Medial septum and the basal nucleus areas of the basal forebrain project to the frontal cortex and the Hippocampus, and degeneration of the cholinergic basal forebrain neuron is a common feature of Alzheimer’s disease(AD) and vascular dementia and it has been correlated with cognitive decline. This research studied to verify the effects of cholinergic neuron in basal forebrain and the role of hippocampus and frontal cortex on recognition through recognition test and immunohistochemistry after damaging cholinergic neuron of the basal forebrain by intraventricular injection of 192 IgG-saporin. 192 IgG-saporin of 8ul (0.63ug/ul) was injected to the bilateral lateral ventricle of rats. After 2 weeks, Novel object recognition (NOR) test and Object in place (OIP) test was conducted to elucidate damage of cholinergic neuron. After completing the behavioral test, the ChAT cholinergic neuron in the brain was ascertained to confirm with immunohistochemistry if cholinergic neuron was damaged. In NOR test, the lesion group with 192 IgG-saporin showed 10% lower novel object preference than normal group. In OIP test, the normal group showed 50% novel object preference and the lesion group with 192 IgG-saporin showed 30% novel object preference in an hour delay test. On the other hand, the normal group and the lesion group with 192 IgG-saporin shoed 33% and 35% novel object preference respectively in a day delay test. However, this rate is not that significant value enough to elucidate behavioral difference between normal group and lesion group. In immunohistochemistry, the number of cholinergic neuron was remarkably decreased in basal forebrain. According to both of the behavioral tests, lesion group seem to less remember novel object than normal group. Also, they searched less the novel object that changed its location than normal group in the short term condition. However, there was no significant difference in the long term condition. These results suggest that the lesion with 192 IgG-saporin can damage spatial working memory.In the Immunohistochemistry result of the lesion condition, cholinergic input to hippocampus in basal forebrain affects recognition. However, the effect is not so essential.
Related Products: 192-IgG-SAP (Cat. #IT-01)
Effects of chronic stress on alterations of GR-PKA-NF-kappa B signaling and spatial learning in rats with cholinergic deafferentation.
Lee S-Y, Ma J, Chung C, Han J-S (2012) Effects of chronic stress on alterations of GR-PKA-NF-kappa B signaling and spatial learning in rats with cholinergic deafferentation. Neuroscience 2012 Abstracts 345.20. Society for Neuroscience, New Orleans, LA.
Summary: Aging and Alzheimer’s disease (AD) is associated with diminished integrity of the cholinergic innervations of the hippocampus and cortex. Previously, we demonstrated that removal of the cholinergic innervations impaired regulation of the HPA axis with response to acute stress and induced changes in the interaction among glucocorticoid receptor (GR), nuclear factor-κB (NF- κB) p65, and the cytoplasmic catalytic subunit of protein kinase A (PKAc) in the hippocampus. The current research examined effects of chronic stress on the altered signaling induced by cholinergic deafferentation. Young adult rats received immunotoxic lesions of basal forebrain cholinergic neurons by intracranial injections of 192 IgG-saporin into the medial septum/vertical limb of the diagonal band and substantia innominata/nucleus basalis. After 2 weeks recovery from surgery, rats with cholinergic lesions and vehicle-injected control rats were subjected to 1 hr restraint stress per day for 2 weeks. Rats with only cholinergic deafferentation or sham-operated rats with chronic stress showed intact spatial learning. Rats with cholinergic deafferentation that received chronic stress showed impairments of spatial learning. And we examined that cholinergic deafferentation induced alterations in GR and NF- κB p65 expression in hippocampus and prefrontal cortex. Thus the loss of cholinergic integrity during aging and in AD may increase proneness to chronic stress.
Related Products: 192-IgG-SAP (Cat. #IT-01)
Cholinergic basal forebrain neurons contribute to the biochemical and electrophysiological changes in the cortex during sleep deprivation.
Kalinchuk AV, Kim S, Mccarley RW, Basheer R (2012) Cholinergic basal forebrain neurons contribute to the biochemical and electrophysiological changes in the cortex during sleep deprivation. Neuroscience 2012 Abstracts 486.24. Society for Neuroscience, New Orleans, LA.
Summary: Short term sleep deprivation (SD) (2-3h) increases the levels of inducible nitric oxide (NO) synthase (iNOS)-mediated NO and adenosine (AD) in the basal forebrain (BF) (Basheer et al., 1999; Kalinchuk et al., 2006). We showed recently that the prolongation of SD for 5h triggers similar biochemical changes in the prefrontal/frontal cortex (PFC/FC), the area which receives projections from the BF (Kalinchuk et al., 2010). Lesion of the BF cholinergic cells using immunotoxin 192-IgG saporin attenuates SD-induced AD increase in the BF and recovery non-rapid eye movement (NREM) sleep response (Kalinchuk et al., 2008). However, it is not known whether the cholinergic cells play a role in SD-induced biochemical changes in the cortex. In the current study we lesioned BF cholinergic cells, and compared SD-induced biochemical changes simultaneously in the PFC and BF in the same animals before and after the lesion. We correlated the changes in the biochemical markers, NO and adenosine, with the changes in electrophysiological markers of homeostatic sleep pressure, encephalogram (EEG) theta power during SD and delta power during recovery NREM sleep after SD. Male rats were implanted with electrodes for EEG/electromyogram (EMG) recording and 2 guide cannulae for microdialysis probes targeting BF and PFC. Microdialysis samples were collected simultaneously from both areas every 30 min during 8h SD. Dialysates were analyzed for AD using high performance liquid chromatography (HPLC)/fluorescent detection and for NO metabolites nitrate and nitrite (NOx) using Fluorimetric Assay Kit (Cayman). The lesion of the BF cholinergic cells was performed using the local injections of 192-IgG saporin into the BF, and similar experiment was repeated 2 weeks after the injection. Histochemical analysis confirmed the localization of the probes in the BF and PFC and the quality of the lesion procedure. Before saporin injection, SD induced increases in the levels of NOx and AD, which became significant after 1h (NOx) and 2h (AD) of SD in the BF and after 4h (NOx) and 5h (AD) of SD in the FC. EEG recording detected increases in the intensity of theta power during SD and delta power during following recovery NREM sleep. 2 weeks after saporin injection, SD-induced changes in NOx and AD were significantly attenuated both in the BF and the PFC. Also the increases in theta and delta power were significantly attenuated. We conclude that cholinergic neurons of the BF, which provide strong activating input to the PFC, contribute to the generation of homeostatic sleep pressure during SD, including its biochemical and electrophysiological correlates.
Related Products: 192-IgG-SAP (Cat. #IT-01)
The effect of the steroid sulfatase inhibitor (p-O-sulfamoyl)-tetradecanoyl tyramine (DU-14) on learning and memory in rats with selective lesion of septal-hippocampal cholinergic tract.
Babalola PA, Fitz NF, Gibbs RB, Flaherty PT, Li PK, Johnson DA (2012) The effect of the steroid sulfatase inhibitor (p-O-sulfamoyl)-tetradecanoyl tyramine (DU-14) on learning and memory in rats with selective lesion of septal-hippocampal cholinergic tract. Neurobiol Learn Mem 98(3):303-310. doi: 10.1016/j.nlm.2012.09.003
Summary: Steroid sulfatase inhibitors such as dehydroepiandrosterone (DHEAS) have memory-enhancing effects. Working with both DHEAS and the steroid sulfatase inhibitor DU-14, the authors examined cholinergic function by infusing 0.2 μg of 192-IgG-SAP (Cat. #IT-01) into the medial septum of rats. The results indicate that memory associated with contextual fear is facilitated by steroid sulfatase inhibition, but acquisition of spatial memory is impaired by these same lesions.
Related Products: 192-IgG-SAP (Cat. #IT-01)
Histamine release in the basal forebrain mediates cortical activation through cholinergic neurons.
Zant JC, Rozov S, Wigren HK, Panula P, Porkka-Heiskanen T (2012) Histamine release in the basal forebrain mediates cortical activation through cholinergic neurons. J Neurosci 32(38):13244-13254. doi: 10.1523/JNEUROSCI.5933-11.2012
Summary: The basal forebrain modulates many functions, among them the regulation of wakefulness and cortical arousal. Previous data has linked increases in histaminergic transmission to increases in wakefulness. In order to further investigate various facets of this system, the authors injected 230 ng of 192-IgG-SAP (Cat. #IT-01) into the horizontal diagonal band of Broca/substantia innominata/magnocellular preoptic area of rats. While control animals displayed several changes on administration of exogenous histamine, the lesioned animals had none of these changes.
Related Products: 192-IgG-SAP (Cat. #IT-01)
Time to pay attention: attentional performance time-stamped prefrontal cholinergic activation, diurnality, and performance.
Paolone G, Lee TM, Sarter M (2012) Time to pay attention: attentional performance time-stamped prefrontal cholinergic activation, diurnality, and performance. J Neurosci 32(35):12115-12128. doi: 10.1523/JNEUROSCI.2271-12.2012
Summary: This work examined the role that neuronal mechanisms have in cognitive performance on a fixed-time task. The authors performed bilateral 160 ng infusions of 192-IgG-SAP (Cat. #IT-01) into the nucleus basalis and substantia innominata of the basal forebrain of rats that had reached stable performance on a sustained attention task. In control animals trained in the same task, prefrontal cholinergic neurotransmission persisted at the fixed time even after the task was terminated. Both lesioning and altering the task training time impaired task performance.
Related Products: 192-IgG-SAP (Cat. #IT-01)
Cholinergic denervation attenuates phencyclidine-induced c-fos responses in rat cortical neurons.
Savage S, Mattsson A, Olson L (2012) Cholinergic denervation attenuates phencyclidine-induced c-fos responses in rat cortical neurons. Neuroscience 216:38-45. doi: 10.1016/j.neuroscience.2012.04.064
Summary: Phenylcyclidine (PCP) has been used to model aspects of schizophrenia in animals. 81 ng of 192-IgG-SAP (Cat. #IT-01) was injected into the nucleus basalis magnocellularis of rats to assess the effects of low dose PCP in a cholinergically-deprived system. Saporin (Cat. #PR-01) was used as a control. Results demonstrate basalocortical cholinergic neurons are necessary for PCP to have full effect.
Related Products: 192-IgG-SAP (Cat. #IT-01), Saporin (Cat. #PR-01)
PET imaging of cholinergic deficits in rats using [(18)F]fluoroethoxybenzovesamicol ([(18)F]FEOBV).
Parent M, Bedard MA, Aliaga A, Soucy JP, Landry St-Pierre E, Cyr M, Kostikov A, Schirrmacher E, Massarweh G, Rosa-Neto P (2012) PET imaging of cholinergic deficits in rats using [(18)F]fluoroethoxybenzovesamicol ([(18)F]FEOBV). Neuroimage 62(1):555-561. doi: 10.1016/j.neuroimage.2012.04.032
Summary: In order to better understand and evaluate neurodegenerative diseases imaging agents are necessary to visualize the affected systems. [18F]fluoroethoxybenzovesamicol ([18F]FEOBV) is one such agent that shows promise for labeling the vesicular acetylcholine transporter with positron emission tomography. The authors injected 0.2 μg of 192-IgG-SAP (Cat. #IT-01) into the left hemisphere of rats to model cholinergic terminal loss as seen in aged animals. Loss of these terminals was found to reduce [18F]FEOBV binding in the ventral frontal cortex on the lesioned side, and also in the homologous region of the contralateral hemisphere, allowing detection of both physiological and pathological reduction of cholinergic terminals.
Related Products: 192-IgG-SAP (Cat. #IT-01)