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Atypical electrophysiological and behavioral responses to diazepam in a leading mouse model of Down syndrome. Sci Rep 2021; 11:9521. [PMID: 33947925 PMCID: PMC8096846 DOI: 10.1038/s41598-021-89011-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/15/2021] [Indexed: 02/02/2023] Open
Abstract
Mounting evidence implicates dysfunctional GABAAR-mediated neurotransmission as one of the underlying causes of learning and memory deficits observed in the Ts65Dn mouse model of Down syndrome (DS). The specific origin and nature of such dysfunction is still under investigation, which is an issue with practical consequences to preclinical and clinical research, as well as to the care of individuals with DS and anxiety disorder or those experiencing seizures in emergency room settings. Here, we investigated the effects of GABAAR positive allosteric modulation (PAM) by diazepam on brain activity, synaptic plasticity, and behavior in Ts65Dn mice. We found Ts65Dn mice to be less sensitive to diazepam, as assessed by electroencephalography, long-term potentiation, and elevated plus-maze. Still, diazepam pre-treatment displayed typical effectiveness in reducing susceptibility and severity to picrotoxin-induced seizures in Ts65Dn mice. These findings fill an important gap in the understanding of GABAergic function in a key model of DS.
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2
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Antidepressants that inhibit both serotonin and norepinephrine reuptake impair long-term potentiation in hippocampus. Psychopharmacology (Berl) 2014; 231:4429-41. [PMID: 24781518 PMCID: PMC4214920 DOI: 10.1007/s00213-014-3587-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 04/10/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Monoamine reuptake inhibitors can stimulate expression of brain-derived neurotrophic factor (BDNF) and alter long-term potentiation (LTP), a widely used model for the synaptic mechanisms that underlie memory formation. BDNF expression is upregulated during LTP, and BDNF in turn positively modulates LTP. Previously, we found that treatment with venlafaxine, a serotonin and norepinephrine reuptake inhibitor (SNRI), but not citalopram, a selective serotonin reuptake inhibitor (SSRI), reduced LTP in hippocampal area CA1 without changing hippocampal BDNF protein expression. OBJECTIVES We tested the hypothesis that combined serotonin and norepinephrine reuptake inhibition is necessary for LTP impairment, and we reexamined the potential role of BDNF by testing for region-specific changes in areas CA1, CA3, and dentate gyrus. We also tested whether early events in the LTP signaling pathway were altered to impair LTP. METHODS Animals were treated for 21 days with venlafaxine, imipramine, fluoxetine, or maprotiline. In vitro hippocampal slices were used for electrophysiological measurements. Protein expression was measured by enzyme-linked immunosorbent assay (ELISA) and Western blotting. RESULTS LTP was impaired only following treatment with combined serotonin and norepinephrine reuptake inhibitors (venlafaxine, imipramine) but not with selective serotonin (fluoxetine) or norepinephrine (maprotiline) reuptake inhibitors. BDNF protein expression was not altered by venlafaxine or imipramine treatment, nor were postsynaptic depolarization during LTP inducing stimulation or synaptic membrane NMDA receptor subunit expression affected. CONCLUSIONS LTP is impaired by chronic treatment with antidepressant that inhibit both serotonin and norepinephrine reuptake; this impairment results from changes that are downstream of postsynaptic depolarization and calcium influx.
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Vashchinkina E, Panhelainen A, Aitta-Aho T, Korpi ER. GABAA receptor drugs and neuronal plasticity in reward and aversion: focus on the ventral tegmental area. Front Pharmacol 2014; 5:256. [PMID: 25505414 PMCID: PMC4243505 DOI: 10.3389/fphar.2014.00256] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 11/03/2014] [Indexed: 12/13/2022] Open
Abstract
GABAA receptors are the main fast inhibitory neurotransmitter receptors in the mammalian brain, and targets for many clinically important drugs widely used in the treatment of anxiety disorders, insomnia and in anesthesia. Nonetheless, there are significant risks associated with the long-term use of these drugs particularly related to development of tolerance and addiction. Addictive mechanisms of GABAA receptor drugs are poorly known, but recent findings suggest that those drugs may induce aberrant neuroadaptations in the brain reward circuitry. Recently, benzodiazepines, acting on synaptic GABAA receptors, and modulators of extrasynaptic GABAA receptors (THIP and neurosteroids) have been found to induce plasticity in the ventral tegmental area (VTA) dopamine neurons and their main target projections. Furthermore, depending whether synaptic or extrasynaptic GABAA receptor populations are activated, the behavioral outcome of repeated administration seems to correlate with rewarding or aversive behavioral responses, respectively. The VTA dopamine neurons project to forebrain centers such as the nucleus accumbens and medial prefrontal cortex, and receive afferent projections from these brain regions and especially from the extended amygdala and lateral habenula, forming the major part of the reward and aversion circuitry. Both synaptic and extrasynaptic GABAA drugs inhibit the VTA GABAergic interneurons, thus activating the VTA DA neurons by disinhibition and this way inducing glutamatergic synaptic plasticity. However, the GABAA drugs failed to alter synaptic spine numbers as studied from Golgi-Cox-stained VTA dendrites. Since the GABAergic drugs are known to depress the brain metabolism and gene expression, their likely way of inducing neuroplasticity in mature neurons is by disinhibiting the principal neurons, which remains to be rigorously tested for a number of clinically important anxiolytics, sedatives and anesthetics in different parts of the circuitry.
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Affiliation(s)
- Elena Vashchinkina
- Department of Pharmacology, Institute of Biomedicine, University of Helsinki Helsinki, Finland
| | - Anne Panhelainen
- Institute of Biotechnology, University of Helsinki Helsinki, Finland
| | - Teemu Aitta-Aho
- Department of Pharmacology, Institute of Biomedicine, University of Helsinki Helsinki, Finland ; Department of Pharmacology, University of Cambridge Cambridge, UK
| | - Esa R Korpi
- Department of Pharmacology, Institute of Biomedicine, University of Helsinki Helsinki, Finland ; Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, and SINAPSE, Singapore Institute for Neurotechnology Singapore, Singapore
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Berdyyeva T, Otte S, Aluisio L, Ziv Y, Burns LD, Dugovic C, Yun S, Ghosh KK, Schnitzer MJ, Lovenberg T, Bonaventure P. Zolpidem reduces hippocampal neuronal activity in freely behaving mice: a large scale calcium imaging study with miniaturized fluorescence microscope. PLoS One 2014; 9:e112068. [PMID: 25372144 PMCID: PMC4221229 DOI: 10.1371/journal.pone.0112068] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 10/07/2014] [Indexed: 11/18/2022] Open
Abstract
Therapeutic drugs for cognitive and psychiatric disorders are often characterized by their molecular mechanism of action. Here we demonstrate a new approach to elucidate drug action on large-scale neuronal activity by tracking somatic calcium dynamics in hundreds of CA1 hippocampal neurons of pharmacologically manipulated behaving mice. We used an adeno-associated viral vector to express the calcium sensor GCaMP3 in CA1 pyramidal cells under control of the CaMKII promoter and a miniaturized microscope to observe cellular dynamics. We visualized these dynamics with and without a systemic administration of Zolpidem, a GABAA agonist that is the most commonly prescribed drug for the treatment of insomnia in the United States. Despite growing concerns about the potential adverse effects of Zolpidem on memory and cognition, it remained unclear whether Zolpidem alters neuronal activity in the hippocampus, a brain area critical for cognition and memory. Zolpidem, when delivered at a dose known to induce and prolong sleep, strongly suppressed CA1 calcium signaling. The rate of calcium transients after Zolpidem administration was significantly lower compared to vehicle treatment. To factor out the contribution of changes in locomotor or physiological conditions following Zolpidem treatment, we compared the cellular activity across comparable epochs matched by locomotor and physiological assessments. This analysis revealed significantly depressive effects of Zolpidem regardless of the animal's state. Individual hippocampal CA1 pyramidal cells differed in their responses to Zolpidem with the majority (∼ 65%) significantly decreasing the rate of calcium transients, and a small subset (3%) showing an unexpected and significant increase. By linking molecular mechanisms with the dynamics of neural circuitry and behavioral states, this approach has the potential to contribute substantially to the development of new therapeutics for the treatment of CNS disorders.
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Affiliation(s)
- Tamara Berdyyeva
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Stephani Otte
- Inscopix, Palo Alto, California, United States of America
| | - Leah Aluisio
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Yaniv Ziv
- Inscopix, Palo Alto, California, United States of America
| | | | - Christine Dugovic
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Sujin Yun
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Kunal K. Ghosh
- Inscopix, Palo Alto, California, United States of America
| | | | - Timothy Lovenberg
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Pascal Bonaventure
- Janssen Research & Development, LLC, San Diego, California, United States of America
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Licata SC, Shinday NM, Huizenga MN, Darnell SB, Sangrey GR, Rudolph U, Rowlett JK, Sadri-Vakili G. Alterations in brain-derived neurotrophic factor in the mouse hippocampus following acute but not repeated benzodiazepine treatment. PLoS One 2013; 8:e84806. [PMID: 24367698 PMCID: PMC3868703 DOI: 10.1371/journal.pone.0084806] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 11/19/2013] [Indexed: 12/24/2022] Open
Abstract
Benzodiazepines (BZs) are safe drugs for treating anxiety, sleep, and seizure disorders, but their use also results in unwanted effects including memory impairment, abuse, and dependence. The present study aimed to reveal the molecular mechanisms that may contribute to the effects of BZs in the hippocampus (HIP), an area involved in drug-related plasticity, by investigating the regulation of immediate early genes following BZ administration. Previous studies have demonstrated that both brain derived neurotrophic factor (BDNF) and c-Fos contribute to memory- and abuse-related processes that occur within the HIP, and their expression is altered in response to BZ exposure. In the current study, mice received acute or repeated administration of BZs and HIP tissue was analyzed for alterations in BDNF and c-Fos expression. Although no significant changes in BDNF or c-Fos were observed in response to twice-daily intraperitoneal (i.p.) injections of diazepam (10 mg/kg + 5 mg/kg) or zolpidem (ZP; 2.5 mg/kg + 2.5 mg/kg), acute i.p. administration of both triazolam (0.03 mg/kg) and ZP (1.0 mg/kg) decreased BDNF protein levels within the HIP relative to vehicle, without any effect on c-Fos. ZP specifically reduced exon IV-containing BDNF transcripts with a concomitant increase in the association of methyl-CpG binding protein 2 (MeCP2) with BDNF promoter IV, suggesting that MeCP2 activity at this promoter may represent a ZP-specific mechanism for reducing BDNF expression. ZP also increased the association of phosphorylated cAMP response element binding protein (pCREB) with BDNF promoter I. Future work should examine the interaction between ZP and DNA as the cause for altered gene expression in the HIP, given that BZs can enter the nucleus and intercalate into DNA directly.
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Affiliation(s)
- Stephanie C. Licata
- McLean Hospital, Belmont, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Nina M. Shinday
- New England Primate Research Center, Southborough, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Megan N. Huizenga
- Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Shayna B. Darnell
- Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Gavin R. Sangrey
- Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Uwe Rudolph
- McLean Hospital, Belmont, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - James K. Rowlett
- New England Primate Research Center, Southborough, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ghazaleh Sadri-Vakili
- Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
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Levenga J, Krishnamurthy P, Rajamohamedsait H, Wong H, Franke TF, Cain P, Sigurdsson EM, Hoeffer CA. Tau pathology induces loss of GABAergic interneurons leading to altered synaptic plasticity and behavioral impairments. Acta Neuropathol Commun 2013; 1:34. [PMID: 24252661 PMCID: PMC3893396 DOI: 10.1186/2051-5960-1-34] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 07/03/2013] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Tau is a microtubule stabilizing protein and is mainly expressed in neurons. Tau aggregation into oligomers and tangles is considered an important pathological event in tauopathies, such as frontotemporal dementia (FTD) and Alzheimer's disease (AD). Tauopathies are also associated with deficits in synaptic plasticity such as long-term potentiation (LTP), but the specific role of tau in the manifestation of these deficiencies is not well-understood. We examined long lasting forms of synaptic plasticity in JNPL3 (BL6) mice expressing mutant tau that is identified in some inherited FTDs. RESULTS We found that aged (>12 months) JNPL3 (BL6) mice exhibit enhanced hippocampal late-phase (L-LTP), while young JNPL3 (BL6) mice (age 6 months) displayed normal L-LTP. This enhanced L-LTP in aged JNPL3 (BL6) mice was rescued with the GABAAR agonist, zolpidem, suggesting a loss of GABAergic function. Indeed, we found that mutant mice displayed a reduction in hippocampal GABAergic interneurons. Finally, we also found that expression of mutant tau led to severe sensorimotor-gating and hippocampus-dependent memory deficits in the aged JNPL3 (BL6) mice. CONCLUSIONS We show for the first time that hippocampal GABAergic function is impaired by pathological tau protein, leading to altered synaptic plasticity and severe memory deficits. Increased understanding of the molecular mechanisms underlying the synaptic failure in AD and FTD is critical to identifying targets for therapies to restore cognitive deficiencies associated with tauopathies.
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Bazyan AS, van Luijtelaar G. Neurochemical and behavioral features in genetic absence epilepsy and in acutely induced absence seizures. ISRN NEUROLOGY 2013; 2013:875834. [PMID: 23738145 PMCID: PMC3664506 DOI: 10.1155/2013/875834] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 02/06/2013] [Indexed: 02/08/2023]
Abstract
The absence epilepsy typical electroencephalographic pattern of sharp spikes and slow waves (SWDs) is considered to be due to an interaction of an initiation site in the cortex and a resonant circuit in the thalamus. The hyperpolarization-activated cyclic nucleotide-gated cationic I h pacemaker channels (HCN) play an important role in the enhanced cortical excitability. The role of thalamic HCN in SWD occurrence is less clear. Absence epilepsy in the WAG/Rij strain is accompanied by deficiency of the activity of dopaminergic system, which weakens the formation of an emotional positive state, causes depression-like symptoms, and counteracts learning and memory processes. It also enhances GABAA receptor activity in the striatum, globus pallidus, and reticular thalamic nucleus, causing a rise of SWD activity in the cortico-thalamo-cortical networks. One of the reasons for the occurrence of absences is that several genes coding of GABAA receptors are mutated. The question arises: what the role of DA receptors is. Two mechanisms that cause an infringement of the function of DA receptors in this genetic absence epilepsy model are proposed.
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Affiliation(s)
- A. S. Bazyan
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Science, Russian Federation, 5A Butlerov Street, Moscow 117485, Russia
| | - G. van Luijtelaar
- Biological Psychology, Donders Centre for Cognition, Donders Institute for Brain, Cognition and Behavior, Radboud University Nijmegen, P.O. Box 9104, 6500 HE Nijmegen, The Netherlands
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8
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Zanin KA, Patti CL, Sanday L, Fernandes-Santos L, Oliveira LC, Poyares D, Tufik S, Frussa-Filho R. Effects of zolpidem on sedation, anxiety, and memory in the plus-maze discriminative avoidance task. Psychopharmacology (Berl) 2013; 226:459-74. [PMID: 22729271 DOI: 10.1007/s00213-012-2756-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 05/21/2012] [Indexed: 01/01/2023]
Abstract
RATIONALE Zolpidem (Zolp), a hypnotic drug prescribed to treat insomnia, may have negative effects on memory, but reports are inconsistent. OBJECTIVES We examined the effects of acute doses of Zolp (2, 5, or 10 mg/kg, i.p.) on memory formation (learning, consolidation, and retrieval) using the plus-maze discriminative avoidance task. METHODS Mice were acutely treated with Zolp 30 min before training or testing. In addition, the effects of Zolp and midazolam (Mid; a classic benzodiazepine) on consolidation at different time points were examined. The possible role of state dependency was investigated using combined pre-training and pre-test treatments. RESULTS Zolp produced a dose-dependent sedative effect, without modifying anxiety-like behavior. The pre-training administration of 5 or 10 mg/kg resulted in retention deficits. When administered immediately after training or before testing, memory was preserved. Zolp post-training administration (2 or 3 h) impaired subsequent memory. There was no participation of state dependency phenomenon in the amnestic effects of Zolp. Similar to Zolp, Mid impaired memory consolidation when administered 1 h after training. CONCLUSIONS Amnestic effects occurred when Zolp was administered either before or 2-3 h after training. These memory deficits are not related to state dependency. Moreover, Zolp did not impair memory retrieval. Notably, the memory-impairing effects of Zolp are similar to those of Mid, with the exception of the time point at which the drug can modify consolidation. Finally, the memory effects were unrelated to sedation or anxiolysis.
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Affiliation(s)
- Karina A Zanin
- Departamento de Psicobiologia, Universidade Federal de São Paulo, R. Napoleão de Barros, 925, 04024002 São Paulo, SP, Brazil
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Abstract
Over more than a century of research has established the fact that sleep benefits the retention of memory. In this review we aim to comprehensively cover the field of "sleep and memory" research by providing a historical perspective on concepts and a discussion of more recent key findings. Whereas initial theories posed a passive role for sleep enhancing memories by protecting them from interfering stimuli, current theories highlight an active role for sleep in which memories undergo a process of system consolidation during sleep. Whereas older research concentrated on the role of rapid-eye-movement (REM) sleep, recent work has revealed the importance of slow-wave sleep (SWS) for memory consolidation and also enlightened some of the underlying electrophysiological, neurochemical, and genetic mechanisms, as well as developmental aspects in these processes. Specifically, newer findings characterize sleep as a brain state optimizing memory consolidation, in opposition to the waking brain being optimized for encoding of memories. Consolidation originates from reactivation of recently encoded neuronal memory representations, which occur during SWS and transform respective representations for integration into long-term memory. Ensuing REM sleep may stabilize transformed memories. While elaborated with respect to hippocampus-dependent memories, the concept of an active redistribution of memory representations from networks serving as temporary store into long-term stores might hold also for non-hippocampus-dependent memory, and even for nonneuronal, i.e., immunological memories, giving rise to the idea that the offline consolidation of memory during sleep represents a principle of long-term memory formation established in quite different physiological systems.
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Affiliation(s)
- Björn Rasch
- Division of Biopsychology, Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland.
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Mednick SC, McDevitt EA, Walsh JK, Wamsley E, Paulus M, Kanady JC, Drummond SPA. The critical role of sleep spindles in hippocampal-dependent memory: a pharmacology study. J Neurosci 2013; 33:4494-504. [PMID: 23467365 PMCID: PMC3744388 DOI: 10.1523/jneurosci.3127-12.2013] [Citation(s) in RCA: 205] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 01/10/2013] [Accepted: 01/16/2013] [Indexed: 11/21/2022] Open
Abstract
An important function of sleep is the consolidation of memories, and features of sleep, such as rapid eye movement (REM) or sleep spindles, have been shown to correlate with improvements in discrete memory domains. Because of the methodological difficulties in modulating sleep, however, a causal link between specific sleep features and human memory consolidation is lacking. Here, we experimentally manipulated specific sleep features during a daytime nap via direct pharmacological intervention. Using zolpidem (Ambien), a short-acting GABAA agonist hypnotic, we show increased sleep spindle density and decreased REM sleep compared with placebo and sodium oxybate (Xyrem). Naps with increased spindles produced significantly better verbal memory and significantly worse perceptual learning but did not affect motor learning. The experimental spindles were similar to control spindles in amplitude and frequency, suggesting that the experimental intervention enhanced normal sleep processes. Furthermore, using statistical methods, we demonstrate for the first time a critical role of spindles in human hippocampal memory performance. The gains in memory consolidation exceed sleep-alone or control conditions and demonstrate the potential for targeted, exceptional memory enhancement in healthy adults with pharmacologically modified sleep.
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Affiliation(s)
- Sara C Mednick
- Department of Psychology, University of California Riverside, Riverside, California 92521, USA.
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Sasaki-Hamada S, Sacai H, Sugiyama A, Iijima T, Saitoh A, Inagaki M, Yamada M, Oka JI. Riluzole Does Not Affect Hippocampal Synaptic Plasticity and Spatial Memory, Which Are Impaired by Diazepam in Rats. J Pharmacol Sci 2013; 122:232-6. [DOI: 10.1254/jphs.13052sc] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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12
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Midazolam impairs acquisition and retrieval, but not consolidation of reference memory in the Morris water maze. Behav Brain Res 2012; 241:198-205. [PMID: 23261388 DOI: 10.1016/j.bbr.2012.12.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 12/07/2012] [Accepted: 12/10/2012] [Indexed: 01/10/2023]
Abstract
Amnesia is one of the most discussed properties of the benzodiazepine class of drugs. The effects of benzodiazepines on human memory are usually anterograde, while changes in retrograde memory functions were seldom reported. Such inconsistent findings have prompted numerous animal studies investigating the influences of these positive modulators of inhibitory neurotransmission on different stages of memory. Among the benzodiazepines, memory effects of midazolam are of special interest due to its many and varied clinical applications. The present Morris water maze study in adult male Wistar rats was performed in three experiments in which midazolam was administered at doses of 0.5, 1 and 2 mg/kg intraperitoneally, before or immediately after each of five daily learning sessions, with two trials in a session, as well as before the probe test. Midazolam impaired acquisition and subsequent retention of spatial learning of the position of the hidden platform even at a pre-training dose of 0.5 mg/kg. This low dose was not associated with impairment of the procedural component of learning, manifested by increased time spent in the periphery of the pool. The lack of midazolam effect on consolidation has not been confounded by the observed below-chance performance of the control group since our additional experiment using diazepam also administered immediately after each of five learning sessions has revealed a similar pattern of results. Finally, midazolam administered before the probe test impaired retrieval of reference memory at all tested doses. Hence, induction of retrograde, besides anterograde amnesia should be kept in mind as a possibility when midazolam is used in clinical settings.
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Takamatsu I, Sekiguchi M, Yonamine R, Wada K, Kazama T. The effect of a new water-soluble sedative-hypnotic drug, JM-1232(-), on long-term potentiation in the CA1 region of the mouse hippocampus. Anesth Analg 2011; 113:1043-9. [PMID: 21788318 DOI: 10.1213/ane.0b013e3182291782] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND JM-1232(-) {(-)-3-[2-(4-methyl-1-piperazinyl)-2-oxoethyl]-2-phenyl-3,5,6,7-tetrahydrocyclopenta[f]isoindol-1(2H)-one} is a new water-soluble sedative-hypnotic drug with affinity for the benzodiazepine binding site on γ-aminobutyric acid A receptors. The effects of JM-1232(-) on synaptic transmission in the brain are not known. In the present study, we investigated the effects of JM-1232(-) on synaptic transmission, synaptic plasticity (i.e., long-term potentiation [LTP] and paired-pulse facilitation), and excitatory/inhibitory postsynaptic currents (EPSCs/IPSCs) of pyramidal neurons in the CA1 region of mouse hippocampal slices. METHODS We recorded Schaffer collateral-evoked field excitatory postsynaptic potentials and EPSCs and IPSCs of pyramidal neurons using whole-cell patch-clamp techniques in the CA1 region of mouse hippocampal slices. RESULTS JM-1232(-) had no significant effect on the field excitatory postsynaptic potentials. Application of JM-1232(-) for 20 minutes before theta-burst stimulation dose dependently impaired LTP. JM-1232(-) impaired paired-pulse facilitation. The benzodiazepine antagonist flumazenil abolished the inhibitory effect of JM-1232(-) on LTP and paired-pulse facilitation. JM-1232(-) had no effect on Schaffer collateral stimulation-evoked EPSCs, whereas it potentiated the amplitude and prolonged the decay of evoked IPSCs in CA1 pyramidal neurons. Flumazenil blocked the effect of JM-1232(-) on the amplitude and decay of evoked IPSCs. JM-1232(-) suppressed the action potential discharge in the CA1 pyramidal neurons during theta-burst stimulation, which was reversed by flumazenil. CONCLUSION JM-1232(-) enhances synaptic inhibition and impairs LTP and paired-pulse facilitation in area CA1 of the mouse hippocampus. These effects were mediated by benzodiazepine binding sites on γ-aminobutyric acid A receptors.
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Affiliation(s)
- Isao Takamatsu
- Department of Anesthesiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan.
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Aton SJ, Seibt J, Dumoulin MC, Coleman T, Shiraishi M, Frank MG. The sedating antidepressant trazodone impairs sleep-dependent cortical plasticity. PLoS One 2009; 4:e6078. [PMID: 19568418 PMCID: PMC2699540 DOI: 10.1371/journal.pone.0006078] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Accepted: 06/02/2009] [Indexed: 01/06/2023] Open
Abstract
Background Recent findings indicate that certain classes of hypnotics that target GABAA receptors impair sleep-dependent brain plasticity. However, the effects of hypnotics acting at monoamine receptors (e.g., the antidepressant trazodone) on this process are unknown. We therefore assessed the effects of commonly-prescribed medications for the treatment of insomnia (trazodone and the non-benzodiazepine GABAA receptor agonists zaleplon and eszopiclone) in a canonical model of sleep-dependent, in vivo synaptic plasticity in the primary visual cortex (V1) known as ocular dominance plasticity. Methodology/Principal Findings After a 6-h baseline period of sleep/wake polysomnographic recording, cats underwent 6 h of continuous waking combined with monocular deprivation (MD) to trigger synaptic remodeling. Cats subsequently received an i.p. injection of either vehicle, trazodone (10 mg/kg), zaleplon (10 mg/kg), or eszopiclone (1–10 mg/kg), and were allowed an 8-h period of post-MD sleep before ocular dominance plasticity was assessed. We found that while zaleplon and eszopiclone had profound effects on sleeping cortical electroencephalographic (EEG) activity, only trazodone (which did not alter EEG activity) significantly impaired sleep-dependent consolidation of ocular dominance plasticity. This was associated with deficits in both the normal depression of V1 neuronal responses to deprived-eye stimulation, and potentiation of responses to non-deprived eye stimulation, which accompany ocular dominance plasticity. Conclusions/Significance Taken together, our data suggest that the monoamine receptors targeted by trazodone play an important role in sleep-dependent consolidation of synaptic plasticity. They also demonstrate that changes in sleep architecture are not necessarily reliable predictors of how hypnotics affect sleep-dependent neural functions.
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Affiliation(s)
- Sara J. Aton
- Department of Neuroscience, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Julie Seibt
- Department of Neuroscience, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Michelle C. Dumoulin
- Department of Neuroscience, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Tammi Coleman
- Department of Neuroscience, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Mia Shiraishi
- Department of Neuroscience, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Marcos G. Frank
- Department of Neuroscience, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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15
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Pereira EC, Lucetti DL, Barbosa-Filho JM, de Brito EM, Monteiro VS, Patrocínio MCA, de Moura RR, Leal LKAM, Macedo DS, de Sousa FCF, de Barros Viana GS, Vasconcelos SMM. Coumarin effects on amino acid levels in mice prefrontal cortex and hippocampus. Neurosci Lett 2009; 454:139-42. [DOI: 10.1016/j.neulet.2009.03.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Revised: 03/02/2009] [Accepted: 03/03/2009] [Indexed: 12/24/2022]
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16
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Hu XD, Ge YX, Hu NW, Zhang HM, Zhou LJ, Zhang T, Li WM, Han YF, Liu XG. Diazepam inhibits the induction and maintenance of LTP of C-fiber evoked field potentials in spinal dorsal horn of rats. Neuropharmacology 2006; 50:238-44. [PMID: 16324725 DOI: 10.1016/j.neuropharm.2005.09.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2004] [Revised: 09/25/2005] [Accepted: 09/26/2005] [Indexed: 11/16/2022]
Abstract
The benzodiazepine diazepam impairs memory and long-term potentiation (LTP) in the hippocampus. Here, we investigate the effect of diazepam on LTP of C-fiber evoked field potentials in spinal dorsal horn, which is relevant to pathological pain. LTP of C-fiber evoked field potentials was recorded in the superficial layers of spinal dorsal horn in urethane-anesthetized Sprague--Dawley rats. Diazepam was applied locally at the recording spinal segments before and after LTP induction by tetanic stimulation. We found (1) Diazepam completely blocked LTP induction. (2) Diazepam and midazolam reversed spinal LTP, when applied at 30 min after LTP induction and depressed but could not reverse spinal LTP, when applied at 3 h after LTP induction. (3) Pretreatment with benzodiazepine receptor antagonist flumazenil or GABA(A) receptor antagonist bicuculline completely blocked the inhibitory effects of diazepam on spinal LTP. In contrast, when the inhibitory effect of diazepam was fully established, neither of these antagonists was capable of reversing the inhibition by diazepam. (4) Spinal application of the GABA(A) receptor agonist 3-amino-1-propanesulfonic acid (3-APSA) at a dose of 50 microg, produced a transient inhibition of spinal LTP. These results suggest that diazepam might prevent and depress spinal plastic change produced by noxious stimulation via activation of the GABA(A) -benzodiazepine receptor complex.
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Affiliation(s)
- Xiao-Dong Hu
- Department of Physiology, Zhongshan Medical School of Sun Yat-sen University, 74 Zhongshan Rd 2, Guangzhou 510089, PR China
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17
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van Rijnsoever C, Täuber M, Choulli MK, Keist R, Rudolph U, Mohler H, Fritschy JM, Crestani F. Requirement of alpha5-GABAA receptors for the development of tolerance to the sedative action of diazepam in mice. J Neurosci 2005; 24:6785-90. [PMID: 15282283 PMCID: PMC6729721 DOI: 10.1523/jneurosci.1067-04.2004] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Despite its pharmacological relevance, the mechanism of the development of tolerance to the action of benzodiazepines is essentially unknown. The acute sedative action of diazepam is mediated via alpha1-GABA(A) receptors. Therefore, we tested whether chronic activation of these receptors by diazepam is sufficient to induce tolerance to its sedative action. Knock-in mice, in which thealpha1-,alpha2-,alpha3-, oralpha(5)-GABA(A) receptors had been rendered insensitive to diazepam by histidine-arginine point mutation, were chronically treated with diazepam (8 d; 15 mg x kg(-1) x d(-1)) and tested for motor activity. Wild-type, alpha2(H101R), and alpha3(H126R) mice showed a robust diminution of the motor-depressant drug action. In contrast, alpha5(H105R) mice failed to display any sedative tolerance. alpha1(H101R) mice showed no alteration of motor activity with chronic diazepam treatment. Autoradiography with [3H]flumazenil revealed no change in benzodiazepine binding sites. However, a decrease in alpha5-subunit radioligand binding was detected selectively in the dentate gyrus with specific ligands. This alteration was observed only in diazepam-tolerant animals, indicating that the manifestation of tolerance to the sedative action of diazepam is associated with a downregulation of alpha5-GABA(A) receptors in the dentate gyrus. Thus, the chronic activation of alpha(5)-GABA(A) receptors is crucial for the normal development of sedative tolerance to diazepam, which manifests itself in conjunction with alpha1-GABA(A) receptors.
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18
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Heinen K, Baker RE, Spijker S, Rosahl T, van Pelt J, Brussaard AB. Impaired dendritic spine maturation in GABAA receptor α1 subunit knock out mice. Neuroscience 2003; 122:699-705. [PMID: 14622913 DOI: 10.1016/s0306-4522(03)00477-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In this study we investigated the functional implications of GABAA receptor alpha1 subunit deletion on dendritic arborization and spine maturation in the visual cortex. This subunit is normally strongly upregulated during early postnatal development. Our main finding is that mice lacking the GABAA receptor alpha1 subunit displayed an increased density of dendritic filopodia during the second and third postnatal weeks. However, there was a concomitant decreased density of mature mushroom-shaped spines, which became more pronounced in adults. In contrast, dendritic arborization was not altered in these mice. We propose that an increased efficacy of the inhibitory synaptic transmission in the alpha1 knock out mice may lead to an enhancement of the outgrowth of filopodia around eye opening, but to a failure in spine maturation at later stages.
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Affiliation(s)
- K Heinen
- Department of Experimental Neurophysiology, Research Institute Neurosciences, Faculty of Earth and Life Sciences and Centre for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, de Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
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19
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Hsu FC, Smith SS. Progesterone withdrawal reduces paired-pulse inhibition in rat hippocampus: dependence on GABA(A) receptor alpha4 subunit upregulation. J Neurophysiol 2003; 89:186-98. [PMID: 12522171 PMCID: PMC2887349 DOI: 10.1152/jn.00195.2002] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Withdrawal from the endogenous steroid progesterone (P) after chronic administration increases anxiety and seizure susceptibility via declining levels of its potent GABA-modulatory metabolite 3alpha-OH-5alpha-pregnan-20-one (3alpha,5alphaTHP). This 3alpha,5alpha-THP withdrawal also results in a decreased decay time constant for GABA-gated current assessed using whole cell patch-clamp techniques on pyramidal cells acutely dissociated from CA1 hippocampus. The purpose of this study was to test the hypothesis that the decreases in total integrated GABA-gated current observed at the level of the isolated pyramidal cell would be manifested as a reduced GABA inhibition at the circuit level following hormone withdrawal. Toward this end, adult, female rats were administered P via subcutaneous capsule for 3 wk using a multiple withdrawal paradigm. We then evaluated paired-pulse inhibition (PPI) of pyramidal neurons in CA1 hippocampus using extracellular recording techniques in hippocampal slices from rats 24 h after removal of the capsule (P withdrawal, P Wd). The population spike (PS) was recorded at the stratum pyramidale following homosynaptic orthodromic stimulation in the nearby stratum radiatum. The threshold for eliciting a response was decreased after P Wd, and the mean PS amplitude was significantly increased compared with control values at this time. Paired pulses with 10-ms inter-pulse intervals were then applied across an intensity range from 2 to 20 times threshold. Evaluation of paired-pulse responses showed a significant 40-50% reduction in PPI for PS recorded in the hippocampal CA1 region after P Wd, suggesting an increase in circuit excitability. At this time, enhancement of PPI by the benzodiazepine lorazepam (LZM; 10 microM) was prevented, while pentobarbital (10 microM) potentiation of PPI was comparable to control levels of response. These data are consistent with upregulation of the alpha4 subunit of the GABA(A) receptor (GABAR) as we have previously shown. Moreover, the reduced PPI caused by P Wd was prevented by suppression of GABAR alpha4-subunit expression following intraventricular administration of specific antisense oligonucleotides (1 microg/h for 72 h). These results demonstrating a reduction in PPI following P Wd suggest that GABAergic-mediated recurrent or feed-forward inhibition occurring at the circuit level were decreased following P Wd in female rats, an effect at least partially attributable to alterations in the GABAR subunit gene expression.
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Affiliation(s)
- Fu-Chun Hsu
- Pediatric Regional Epilepsy Program and Joseph Stokes Research Institute of The Children's Hospital of Philadelphia, Pennsylvania 19104, USA
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Akhondzadeh S, Mohammadi MR, Kashani L. Potentiation of muscimol-induced long-term depression by benzodiazepines but not zolpidem. Prog Neuropsychopharmacol Biol Psychiatry 2002; 26:1161-6. [PMID: 12452540 DOI: 10.1016/s0278-5846(02)00254-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Zolpidem is a rapid-onset, short-duration, quickly eliminated imidazopyridine hypnotic. It has been suggested that zolpidem may produce less memory and cognitive impairment than benzodiazepines (BZs) due to its low binding affinity for BZ receptor subtypes found in areas of the brain that are involved in learning and memory, in particular the hippocampus. A novel protocol for inducing long-term synaptic depression through activation of gamma-aminobutyric acid (GABA(A)) receptors in the hippocampal slices has been recently reported. The authors used the CA1 region of rat hippocampal slices to compare the effects of classic BZs, which bind equipotently to BZ1 and BZ2 sites, and of nonbenzodiazepine zolpidem, which binds preferentially to the BZ1 sites of GABA(A) receptors, on the GABA(A)-induced long-term depression (LTD), a possible cellular mechanism for their different cognition-impairment profile. Extracellular recordings were made in the CA1 pyramidal cell layer of rat hippocampal slices following orthodromic stimulation of Schaffer collateral fibres in stratum radiatum (0.01 Hz). It was observed that diazepam and cholordiazepoxide at concentrations of 10 and 20 microM, which did not have any effect themselves on the population spike, potentiate the ability of muscimol to induce LTD, whereas zolpidem at concentrations of 10 and 20 microM failed to potentiate muscimol-induced LTD. The results suggest that the potentiation of muscimol-induced LTD by diazepam or chlordiazepoxide and the lack of this effect by zolpidem may explain their different cognition impairment profiles.
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Affiliation(s)
- Shahin Akhondzadeh
- Roozbeh Psychiatric Hospital, Tehran University of Medical Sciences, South Kargar, Tehran 13334, Iran.
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Bazyan AS, Mel'nik VI, Bikbulatova LS, Karpova MN. The pentylenetetrazole allosteric component of the GABAA receptor plasticity. DOKLADY BIOLOGICAL SCIENCES : PROCEEDINGS OF THE ACADEMY OF SCIENCES OF THE USSR, BIOLOGICAL SCIENCES SECTIONS 2002; 386:400-3. [PMID: 12469399 DOI: 10.1023/a:1020745730228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- A S Bazyan
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, ul. Butlerova 5a, Moscow, Russia
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