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Psyrakis D, Jasiewicz J, Wehrmeister M, Bonni K, Lutz B, Kodirov SA. Progressive long-term synaptic depression at cortical inputs into the amygdala. Neuroscience 2024:S0306-4522(24)00371-3. [PMID: 39094820 DOI: 10.1016/j.neuroscience.2024.07.049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Revised: 07/14/2024] [Accepted: 07/29/2024] [Indexed: 08/04/2024]
Abstract
The convergence of conditioned and unconditioned stimuli (CS and US) into the lateral amygdala (LA) serves as a substrate for an adequate fear response in vivo. This well-known Pavlovian paradigm modulates the synaptic plasticity of neurons, as can be proved by the long-term potentiation (LTP) phenomenon in vitro. Although there is an increasing body of evidence for the existence of LTP in the amygdala, only a few studies were able to show a reliable long-term depression (LTD) of excitation in this structure. We have used coronal brain slices and conducted patch-clamp recordings in pyramidal neurons of the lateral amygdala (LA). After obtaining a stable baseline excitatory postsynaptic current (EPSC) response at a holding potential of -70 mV, we employed a paired-pulse paradigm at 1 Hz at the same membrane potential and could observe a reliable LTD. The different durations of stimulation (ranging between 1.5 - 24 min) were tested first in the same neuron, but the intensity was kept constant. The latter paradigm resulted in a step-wise LTD with a gradually increasing magnitude under these conditions.
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Affiliation(s)
- Dimitrios Psyrakis
- Institute of Physiological Chemistry and Pathobiochemistry, University Medical Center Mainz, Mainz, Germany
| | - Julia Jasiewicz
- Institute of Physiological Chemistry and Pathobiochemistry, University Medical Center Mainz, Mainz, Germany
| | - Michael Wehrmeister
- Institute of Physiological Chemistry and Pathobiochemistry, University Medical Center Mainz, Mainz, Germany
| | - Kathrin Bonni
- Institute of Physiological Chemistry and Pathobiochemistry, University Medical Center Mainz, Mainz, Germany
| | - Beat Lutz
- Institute of Physiological Chemistry and Pathobiochemistry, University Medical Center Mainz, Mainz, Germany
| | - Sodikdjon A Kodirov
- Institute of Physiological Chemistry and Pathobiochemistry, University Medical Center Mainz, Mainz, Germany; Center for Biomedical Studies, Department of Biological Sciences, University of Texas at Brownsville, Texas 78520, USA; Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal; Institute of Biophysics, Johannes Kepler University, Linz, Austria.
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2
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Wilhelm M, Sych Y, Fomins A, Alatorre Warren JL, Lewis C, Serratosa Capdevila L, Boehringer R, Amadei EA, Grewe B, O'Connor EC, Hall BJ, Helmchen F. Striatum-projecting prefrontal cortex neurons support working memory maintenance. Nat Commun 2023; 14:7016. [PMID: 37919287 PMCID: PMC10622437 DOI: 10.1038/s41467-023-42777-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 10/20/2023] [Indexed: 11/04/2023] Open
Abstract
Neurons in the medial prefrontal cortex (mPFC) are functionally linked to working memory (WM) but how distinct projection pathways contribute to WM remains unclear. Based on optical recordings, optogenetic perturbations, and pharmacological interventions in male mice, we report here that dorsomedial striatum (dmStr)-projecting mPFC neurons are essential for WM maintenance, but not encoding or retrieval, in a T-maze spatial memory task. Fiber photometry of GCaMP6m-labeled mPFC→dmStr neurons revealed strongest activity during the maintenance period, and optogenetic inhibition of these neurons impaired performance only when applied during this period. Conversely, enhancing mPFC→dmStr pathway activity-via pharmacological suppression of HCN1 or by optogenetic activation during the maintenance period-alleviated WM impairment induced by NMDA receptor blockade. Moreover, cellular-resolution miniscope imaging revealed that >50% of mPFC→dmStr neurons are active during WM maintenance and that this subpopulation is distinct from neurons active during encoding and retrieval. In all task periods, neuronal sequences were evident. Striatum-projecting mPFC neurons thus critically contribute to spatial WM maintenance.
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Affiliation(s)
- Maria Wilhelm
- Brain Research Institute, University of Zurich, 8057, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, 8057, Zurich, Switzerland
- Institute for Neuroscience, ETH Zurich, 8057, Zurich, Switzerland
| | - Yaroslav Sych
- Brain Research Institute, University of Zurich, 8057, Zurich, Switzerland
- Institute of Cellular and Integrative Neuroscience, CNRS, University of Strasbourg, Strasbourg, France
| | - Aleksejs Fomins
- Brain Research Institute, University of Zurich, 8057, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, 8057, Zurich, Switzerland
| | - José Luis Alatorre Warren
- Brain Research Institute, University of Zurich, 8057, Zurich, Switzerland
- Center for Lifespan Changes in Brain and Cognition, University of Oslo, Oslo, 0317, Norway
| | - Christopher Lewis
- Brain Research Institute, University of Zurich, 8057, Zurich, Switzerland
| | | | - Roman Boehringer
- Institute of Neuroinformatics, University of Zurich and ETH Zurich, 8057, Zurich, Switzerland
| | - Elizabeth A Amadei
- Institute of Neuroinformatics, University of Zurich and ETH Zurich, 8057, Zurich, Switzerland
| | - Benjamin Grewe
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, 8057, Zurich, Switzerland
- Institute of Neuroinformatics, University of Zurich and ETH Zurich, 8057, Zurich, Switzerland
- University Research Priority Program (URPP) Adaptive Brain Circuits in Development and Learning (AdaBD), University of Zurich, Zurich, Switzerland
| | - Eoin C O'Connor
- Neuroscience & Rare Diseases, Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Benjamin J Hall
- Neuroscience & Rare Diseases, Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
- Circuit Biology Department, H. Lundbeck A/S, Valby, Denmark
| | - Fritjof Helmchen
- Brain Research Institute, University of Zurich, 8057, Zurich, Switzerland.
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, 8057, Zurich, Switzerland.
- University Research Priority Program (URPP) Adaptive Brain Circuits in Development and Learning (AdaBD), University of Zurich, Zurich, Switzerland.
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Cichon J, Wasilczuk AZ, Looger LL, Contreras D, Kelz MB, Proekt A. Ketamine triggers a switch in excitatory neuronal activity across neocortex. Nat Neurosci 2023; 26:39-52. [PMID: 36424433 PMCID: PMC10823523 DOI: 10.1038/s41593-022-01203-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 10/13/2022] [Indexed: 11/27/2022]
Abstract
The brain can become transiently disconnected from the environment while maintaining vivid, internally generated experiences. This so-called 'dissociated state' can occur in pathological conditions and under the influence of psychedelics or the anesthetic ketamine (KET). The cellular and circuit mechanisms producing the dissociative state remain poorly understood. We show in mice that KET causes spontaneously active neurons to become suppressed while previously silent neurons become spontaneously activated. This switch occurs in all cortical layers and different cortical regions, is induced by both systemic and cortical application of KET and is mediated by suppression of parvalbumin and somatostatin interneuron activity and inhibition of NMDA receptors and HCN channels. Combined, our results reveal two largely non-overlapping cortical neuronal populations-one engaged in wakefulness, the other contributing to the KET-induced brain state-and may lay the foundation for understanding how the brain might become disconnected from the surrounding environment while maintaining internal subjective experiences.
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Affiliation(s)
- Joseph Cichon
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - Andrzej Z Wasilczuk
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Loren L Looger
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Diego Contreras
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Max B Kelz
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Alex Proekt
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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Zhong W, Darmani NA. The HCN Channel Blocker ZD7288 Induces Emesis in the Least Shrew ( Cryptotis parva). Front Pharmacol 2021; 12:647021. [PMID: 33995059 PMCID: PMC8117105 DOI: 10.3389/fphar.2021.647021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 04/12/2021] [Indexed: 12/02/2022] Open
Abstract
Subtypes (1-4) of the hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are widely expressed in the central and peripheral nervous systems, as well as the cells of smooth muscles in many organs. They mainly serve to regulate cellular excitability in these tissues. The HCN channel blocker ZD7288 has been shown to reduce apomorphine-induced conditioned taste aversion on saccharin preference in rats suggesting potential antinausea/antiemetic effects. Currently, in the least shew model of emesis we find that ZD7288 induces vomiting in a dose-dependent manner, with maximal efficacies of 100% at 1 mg/kg (i.p.) and 83.3% at 10 µg (i.c.v.). HCN channel subtype (1-4) expression was assessed using immunohistochemistry in the least shrew brainstem dorsal vagal complex (DVC) containing the emetic nuclei (area postrema (AP), nucleus tractus solitarius and dorsal motor nucleus of the vagus). Highly enriched HCN1 and HCN4 subtypes are present in the AP. A 1 mg/kg (i.p.) dose of ZD7288 strongly evoked c-Fos expression and ERK1/2 phosphorylation in the shrew brainstem DVC, but not in the in the enteric nervous system in the jejunum, suggesting a central contribution to the evoked vomiting. The ZD7288-evoked c-Fos expression exclusively occurred in tryptophan hydroxylase 2-positive serotonin neurons of the dorsal vagal complex, indicating activation of serotonin neurons may contribute to ZD7288-induced vomiting. To reveal its mechanism(s) of emetic action, we evaluated the efficacy of diverse antiemetics against ZD7288-evoked vomiting including the antagonists/inhibitors of: ERK1/2 (U0126), L-type Ca2+ channel (nifedipine); store-operated Ca2+ entry (MRS 1845); T-type Ca2+ channel (Z944), IP3R (2-APB), RyR receptor (dantrolene); the serotoninergic type 3 receptor (palonosetron); neurokinin 1 receptor (netupitant), dopamine type 2 receptor (sulpride), and the transient receptor potential vanilloid 1 receptor agonist, resiniferatoxin. All tested antiemetics except sulpride attenuated ZD7288-evoked vomiting to varying degrees. In sum, ZD7288 has emetic potential mainly via central mechanisms, a process which involves Ca2+ signaling and several emetic receptors. HCN channel blockers have been reported to have emetic potential in the clinic since they are currently used/investigated as therapeutic candidates for cancer therapy related- or unrelated-heart failure, pain, and cognitive impairment.
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Affiliation(s)
| | - N. A. Darmani
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA, United States
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Trompoukis G, Rigas P, Leontiadis LJ, Papatheodoropoulos C. I h, GIRK, and KCNQ/Kv7 channels differently modulate sharp wave - ripples in the dorsal and ventral hippocampus. Mol Cell Neurosci 2020; 107:103531. [PMID: 32711112 DOI: 10.1016/j.mcn.2020.103531] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 07/11/2020] [Accepted: 07/16/2020] [Indexed: 12/14/2022] Open
Abstract
Sharp waves and ripples (SPW-Rs) are endogenous transient patterns of hippocampus local network activity implicated in several functions including memory consolidation, and they are diversified between the dorsal and the ventral hippocampus. Ion channels in the neuronal membrane play important roles in cell and local network function. In this study, using transverse slices and field potential recordings from the CA1 field of rat hippocampus we show that GIRK and KCNQ2/3 potassium channels play a higher role in modulating SPW-Rs in the dorsal hippocampus, while Ih and other KCNQ (presumably KCNQ5) channels, contribute to shaping SPW-R activity more in the ventral than in dorsal hippocampus. Specifically, blockade of Ih channels by ZD 7288 reduced the rate of occurrence of SPW-Rs and increased the generation of SPW-Rs in the form of clusters in both hippocampal segments, while enhanced the amplitude of SPW-Rs only in the ventral hippocampus. Most effects of ZD 7288 appeared to be independent of NMDA receptors' activity. However, the effects of blockade of NMDA receptors depended on the functional state of Ih channels in both hippocampal segments. Blockade of GIRK channels by Tertiapin-Q increased the rate of occurrence of SPW-Rs only in the dorsal hippocampus and the probability of clusters in both segments of the hippocampus. Blockade of KCNQ2/3 channels by XE 991 increased the rate of occurrence of SPW-Rs and the probability of clusters in the dorsal hippocampus, and only reduced the clustered generation of SPW-Rs in the ventral hippocampus. The blocker of KCNQ1/2 channels, that also enhances KCNQ5 channels, UCL 2077, increased the probability of clusters and the power of the ripple oscillation in the ventral hippocampus only. These results suggest that GIRK, KCNQ and Ih channels represent a key mechanism for modulation of SPW-R activity which act differently in the dorsal and ventral hippocampus, fundamentally supporting functional diversification along the dorsal-ventral axis of the hippocampus.
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Affiliation(s)
- George Trompoukis
- Laboratory of Physiology, Department of Medicine, University of Patras, Rion, Greece
| | - Pavlos Rigas
- Laboratory of Physiology, Department of Medicine, University of Patras, Rion, Greece
| | - Leonidas J Leontiadis
- Laboratory of Physiology, Department of Medicine, University of Patras, Rion, Greece
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Luo P, He G, Liu D. HCN channels: New targets for the design of an antidepressant with rapid effects. J Affect Disord 2019; 245:764-770. [PMID: 30448761 DOI: 10.1016/j.jad.2018.11.081] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 10/22/2018] [Accepted: 11/11/2018] [Indexed: 12/18/2022]
Abstract
BACKGROUND Major depressive disorder (MDD) is a prevalent neuropsychiatric disease that carries a staggering global burden. Although numerous antidepressants are available on the market, unfortunately, many patients die by committing suicide as a result of the therapeutic lag between treatment initiation and the improvement of depressive symptoms. This therapeutic lag highlights the need for new antidepressants that provide rapid relief of depressive symptoms. METHOD In this review, we discuss the seminal researches on hyperpolarization-activated cyclic nucleotide-gated (HCN) channels in animal models of depression and highlight the substantial evidence supporting the development of rapid-acting antidepressants targeting HCN channels. RESULTS HCN channels are associated with the risk of depression and targeting HCN channels or its auxiliary subunit tetratricopeptide repeat-containing Rab8b-interacting protein (TRIP8b) function may exert a rapid antidepressant-like effect. CONCLUSIONS Compounds acting on HCN subunits or the TRIP8b-HCN interaction site may be excellent candidates for development into effective drugs with rapid antidepressant action.
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Affiliation(s)
- Pan Luo
- Department of Pharmacy, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - GuoFang He
- Department of Pharmacy, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
| | - Dong Liu
- Department of Pharmacy, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
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Zhang K, Xu T, Yuan Z, Wei Z, Yamaki VN, Huang M, Huganir RL, Cai X. Essential roles of AMPA receptor GluA1 phosphorylation and presynaptic HCN channels in fast-acting antidepressant responses of ketamine. Sci Signal 2016; 9:ra123. [PMID: 27965425 DOI: 10.1126/scisignal.aai7884] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Although the molecular mechanism is not clear, the clinically tested drug ketamine has rapid antidepressant action that does not require the multiple weeks of treatment needed for other antidepressant drugs to have an effect. We showed that ketamine potentiated Schaffer collateral-CA1 cell excitatory synaptic transmission in hippocampal slice preparations from rodents and enhanced the phosphorylation of the GluA1 subunit on Ser845 of the AMPA-type glutamate receptor in the hippocampal area CA1. These effects persisted when γ-aminobutyric acid (GABA) receptors were pharmacologically blocked. Ketamine reduced behavioral despair in wild-type mice but had no effect in GluA1 S845A knock-in mutant mice. Presynaptic (CA3 pyramidal cell), but not postsynaptic (CA1 pyramidal cell), deletion of N-methyl-d-aspartate (NMDA)-type glutamate receptors eliminated the ketamine-induced enhancement of excitatory synaptic transmission in hippocampal slices and the antidepressant actions of ketamine in mice. The synaptic and behavioral actions of ketamine were completely occluded by inhibition or deletion of the hyperpolarization-activated cyclic nucleotide-gated channel 1 (HCN1). Our results implicate presynaptic NMDA receptor inhibition followed by reduced activity of presynaptic HCN1 channels, which would result in an increase in glutamate release and postsynaptic glutamate receptor activity, as a mechanism of ketamine action. These data provide a mechanism for changes in synaptic activity that could explain the fast-acting antidepressant effects of this drug.
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Affiliation(s)
- Ke Zhang
- Department of Physiology, Southern Illinois University School of Medicine, 1135 Lincoln Drive, Carbondale, IL 62901, USA
| | - Ting Xu
- Department of Physiology, Southern Illinois University School of Medicine, 1135 Lincoln Drive, Carbondale, IL 62901, USA.,The Institute of Neuroscience, the Second Affiliated Hospital of Guangzhou Medical University, 250 Changgang Road, Guangzhou, Guangdong 51030, China
| | - Zhongmin Yuan
- Department of Physiology, Southern Illinois University School of Medicine, 1135 Lincoln Drive, Carbondale, IL 62901, USA
| | - Zhisheng Wei
- The Institute of Neuroscience, the Second Affiliated Hospital of Guangzhou Medical University, 250 Changgang Road, Guangzhou, Guangdong 51030, China
| | - Vitor Nagai Yamaki
- Department of Physiology, Southern Illinois University School of Medicine, 1135 Lincoln Drive, Carbondale, IL 62901, USA
| | - Mingfa Huang
- The Institute of Neuroscience, the Second Affiliated Hospital of Guangzhou Medical University, 250 Changgang Road, Guangzhou, Guangdong 51030, China
| | - Richard L Huganir
- The Solomon H. Snyder Department of Neuroscience, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA
| | - Xiang Cai
- Department of Physiology, Southern Illinois University School of Medicine, 1135 Lincoln Drive, Carbondale, IL 62901, USA.
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Kodirov SA, Wehrmeister M, Colom L. Nicotine-Mediated ADP to Spike Transition: Double Spiking in Septal Neurons. J Membr Biol 2015; 249:107-18. [PMID: 26463358 DOI: 10.1007/s00232-015-9853-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Accepted: 09/29/2015] [Indexed: 11/25/2022]
Abstract
The majority of neurons in lateral septum (LS) are electrically silent at resting membrane potential. Nicotine transiently excites a subset of neurons and occasionally leads to long lasting bursting activity upon longer applications. We have observed simultaneous changes in frequencies and amplitudes of spontaneous action potentials (AP) in the presence of nicotine. During the prolonged exposure, nicotine increased numbers of spikes within a burst. One of the hallmarks of nicotine effects was the occurrences of double spikes (known also as bursting). Alignment of 51 spontaneous spikes, triggered upon continuous application of nicotine, revealed that the slope of after-depolarizing potential gradually increased (1.4 vs. 3 mV/ms) and neuron fired the second AP, termed as double spiking. A transition from a single AP to double spikes increased the amplitude of after-hyperpolarizing potential. The amplitude of the second (premature) AP was smaller compared to the first one, and this correlation persisted in regard to their duration (half-width). A similar bursting activity in the presence of nicotine, to our knowledge, has not been reported previously in the septal structure in general and in LS in particular.
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Affiliation(s)
- Sodikdjon A Kodirov
- Department of Biological Sciences, Center for Biomedical Studies, University of Texas at Brownsville, Brownsville, TX, 78520, USA.
- Neuroscience Institute, Morehouse School of Medicine, 720 Westview Drive SW, Atlanta, GA, 30310, USA.
| | - Michael Wehrmeister
- Johannes Gutenberg University, 55099, Mainz, Germany
- Heidelberg University, Heidelberg, Germany
| | - Luis Colom
- Department of Biological Sciences, Center for Biomedical Studies, University of Texas at Brownsville, Brownsville, TX, 78520, USA
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Lodge D, Mercier MS. Ketamine and phencyclidine: the good, the bad and the unexpected. Br J Pharmacol 2015; 172:4254-76. [PMID: 26075331 DOI: 10.1111/bph.13222] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 05/29/2015] [Accepted: 06/03/2015] [Indexed: 12/21/2022] Open
Abstract
The history of ketamine and phencyclidine from their development as potential clinical anaesthetics through drugs of abuse and animal models of schizophrenia to potential rapidly acting antidepressants is reviewed. The discovery in 1983 of the NMDA receptor antagonist property of ketamine and phencyclidine was a key step to understanding their pharmacology, including their psychotomimetic effects in man. This review describes the historical context and the course of that discovery and its expansion into other hallucinatory drugs. The relevance of these findings to modern hypotheses of schizophrenia and the implications for drug discovery are reviewed. The findings of the rapidly acting antidepressant effects of ketamine in man are discussed in relation to other glutamatergic mechanisms.
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Affiliation(s)
- D Lodge
- Centre for Synaptic Plasticity, School of Physiology and Pharmacology, University of Bristol, Bristol, UK
| | - M S Mercier
- Centre for Synaptic Plasticity, School of Physiology and Pharmacology, University of Bristol, Bristol, UK
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Yu Y, Cao DQ, Xu HY, Sun M, Huang ZL, Yung WH, Lu N, Huang Y. 5-HT3A receptors are required in long-term depression and AMPA receptor internalization. Neuroscience 2014; 278:105-12. [DOI: 10.1016/j.neuroscience.2014.07.070] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Revised: 07/11/2014] [Accepted: 07/24/2014] [Indexed: 11/28/2022]
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Clonidine Suppresses the Induction of Long-Term Potentiation by Inhibiting HCN Channels at the Schaffer Collateral–CA1 Synapse in Anesthetized Adult Rats. Cell Mol Neurobiol 2013; 33:1075-86. [DOI: 10.1007/s10571-013-9974-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 08/11/2013] [Indexed: 11/25/2022]
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ZD7288 enhances long-term depression at early postnatal medial perforant path-granule cell synapses. Neural Plast 2012; 2012:237913. [PMID: 22792490 PMCID: PMC3390110 DOI: 10.1155/2012/237913] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 05/08/2012] [Accepted: 05/08/2012] [Indexed: 12/21/2022] Open
Abstract
Hyperpolarization-activated, cyclic nucleotide-gated nonselective (HCN) channels modulate both membrane potential and resistance and play a significant role in synaptic plasticity. We compared the influence of HCN channels on long-term depression (LTD) at the medial perforant path-granule cell synapse in early postnatal (P9–15) and adult (P30–60) rats. LTD was elicited in P9–15 slices using low-frequency stimulation (LFS, 900 pulses, 1 Hz; 80 ± 4% of baseline). Application of the specific HCN channel blocker ZD7288 (10 μM) before LFS significantly enhanced LTD (62 ± 4%; P < 0.01), showing HCN channels restrain LTD induction. However, when ZD7288 was applied after LFS, LTD was similar to control values and significantly different from the values obtained with ZD7288 application before LFS (81 ± 5%; P < 0.01), indicating that HCN channels do not modulate LTD expression. LTD in slices from adult rats were only marginally lower compared to those in P9–15 slices (85 ± 6%), but bath application of ZD7288 prior to LFS resulted in the same amount of LTD (85 ± 5%). HCN channels in adult tissue hence lose their modulatory effect. In conclusion, we found that HCN channels at the medial perforant path-granule cell synapse compromise LFS-associated induction, but not expression of LTD in early postnatal, but not in adult, rats.
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