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Singh A, Smith PF, Zheng Y. Targeting the Limbic System: Insights into Its Involvement in Tinnitus. Int J Mol Sci 2023; 24:9889. [PMID: 37373034 DOI: 10.3390/ijms24129889] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/05/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
Tinnitus is originally derived from the Latin verb tinnire, which means "to ring". Tinnitus, a complex disorder, is a result of sentient cognizance of a sound in the absence of an external auditory stimulus. It is reported in children, adults, and older populations. Patients suffering from tinnitus often present with hearing loss, anxiety, depression, and sleep disruption in addition to a hissing and ringing in the ear. Surgical interventions and many other forms of treatment have been only partially effective due to heterogeneity in tinnitus patients and a lack of understanding of the mechanisms of tinnitus. Although researchers across the globe have made significant progress in understanding the underlying mechanisms of tinnitus over the past few decades, tinnitus is still deemed to be a scientific enigma. This review summarises the role of the limbic system in tinnitus development and provides insight into the development of potential target-specific tinnitus therapies.
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Affiliation(s)
- Anurag Singh
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand
- Brain Health Research Centre, University of Otago, Dunedin 9016, New Zealand
- The Eisdell Moore Centre for Research in Hearing and Balance Disorders, University of Auckland, Auckland 1023, New Zealand
| | - Paul F Smith
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand
- Brain Health Research Centre, University of Otago, Dunedin 9016, New Zealand
- The Eisdell Moore Centre for Research in Hearing and Balance Disorders, University of Auckland, Auckland 1023, New Zealand
| | - Yiwen Zheng
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand
- Brain Health Research Centre, University of Otago, Dunedin 9016, New Zealand
- The Eisdell Moore Centre for Research in Hearing and Balance Disorders, University of Auckland, Auckland 1023, New Zealand
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2
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Perin P, Mabou Tagne A, Enrico P, Marino F, Cosentino M, Pizzala R, Boselli C. Cannabinoids, Inner Ear, Hearing, and Tinnitus: A Neuroimmunological Perspective. Front Neurol 2020; 11:505995. [PMID: 33329293 PMCID: PMC7719758 DOI: 10.3389/fneur.2020.505995] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 08/18/2020] [Indexed: 12/14/2022] Open
Abstract
Cannabis has been used for centuries for recreational and therapeutic purposes. Whereas, the recreative uses are based on the psychotropic effect of some of its compounds, its therapeutic effects range over a wide spectrum of actions, most of which target the brain or the immune system. Several studies have found cannabinoid receptors in the auditory system, both at peripheral and central levels, thus raising the interest in cannabinoid signaling in hearing, and especially in tinnitus, which is affected also by anxiety, memory, and attention circuits where cannabinoid effects are well described. Available studies on animal models of tinnitus suggest that cannabinoids are not likely to be helpful in tinnitus treatment and could even be harmful. However, the pharmacology of cannabinoids is very complex, and most studies focused on neural CB1R-based responses. Cannabinoid effects on the immune system (where CB2Rs predominate) are increasingly recognized as essential in understanding nervous system pathological responses, and data on immune cannabinoid targets have emerged in the auditory system as well. In addition, nonclassical cannabinoid targets (such as TRP channels) appear to play an important role in the auditory system as well. This review will focus on neuroimmunological mechanisms for cannabinoid effects and their possible use as protective and therapeutic agents in the ear and auditory system, especially in tinnitus.
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Affiliation(s)
- Paola Perin
- Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy
| | | | | | | | | | - Roberto Pizzala
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Cinzia Boselli
- Department of Drug Sciences, University of Pavia, Pavia, Italy
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3
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Harms L, Parras GG, Michie PT, Malmierca MS. The Role of Glutamate Neurotransmission in Mismatch Negativity (MMN), A Measure of Auditory Synaptic Plasticity and Change-detection. Neuroscience 2020; 456:106-113. [PMID: 32045628 DOI: 10.1016/j.neuroscience.2020.01.046] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 01/23/2020] [Accepted: 01/30/2020] [Indexed: 02/06/2023]
Abstract
Mismatch negativity (MMN) is an electrophysiological signature that occurs in response to unexpected stimuli. It is often referred to as a measure of memory-based change detection, because the elicitation of a prediction error response relies on the formation of a prediction, which in turn, is dependent upon intact memory of previous auditory stimulation. As such, the MMN is altered in conditions in which memory is affected, such as Alzheimer's disease, schizophrenia and healthy aging. The most prominent pharmacological finding for MMN strengthens the link between MMN and synaptic plasticity, as glutamate N-methyl-d-aspartate receptor (NMDA-R) antagonists reduce the MMN response. However, recent data has begun to demonstrate that the link between NMDA-R function and MMN is not as clear as once thought, with low dose and low affinity NMDA-R antagonists observed to facilitate MMN.
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Affiliation(s)
- Lauren Harms
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Australia; Hunter Medical Research Institute, University of Newcastle, Australia; Centre for Brain and Mental Health Research, University of Newcastle, Australia.
| | - Gloria G Parras
- Cognitive and Auditory Neuroscience Laboratory, Institute of Neuroscience of León (INCYL), Salamanca, Spain; The Salamanca Institute for Biomedical Research (IBSAL), Salamanca, Spain
| | - Patricia T Michie
- Hunter Medical Research Institute, University of Newcastle, Australia; Centre for Brain and Mental Health Research, University of Newcastle, Australia; School of Psychology, University of Newcastle, Australia
| | - Manuel S Malmierca
- Cognitive and Auditory Neuroscience Laboratory, Institute of Neuroscience of León (INCYL), Salamanca, Spain; The Salamanca Institute for Biomedical Research (IBSAL), Salamanca, Spain; Department of Cell Biology and Pathology, Faculty of Medicine, University of Salamanca, Salamanca, Spain.
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4
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Neurotransmitter- and Release-Mode-Specific Modulation of Inhibitory Transmission by Group I Metabotropic Glutamate Receptors in Central Auditory Neurons of the Mouse. J Neurosci 2018; 38:8187-8199. [PMID: 30093538 DOI: 10.1523/jneurosci.0603-18.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 06/27/2018] [Accepted: 07/27/2018] [Indexed: 12/21/2022] Open
Abstract
Neuromodulation mediated by metabotropic glutamate receptors (mGluRs) regulates many brain functions. However, the functions of mGluRs in the auditory system under normal and diseased states are not well understood. The medial nucleus of the trapezoid body (MNTB) is a critical nucleus in the auditory brainstem nuclei involved in sound localization. In addition to the classical calyx excitatory inputs, MNTB neurons also receive synaptic inhibition and it remains entirely unknown how this inhibition is regulated. Here, using whole-cell voltage clamp in brain slices, we investigated group I mGluR (mGluR I)-mediated modulation of the glycinergic and GABAergic inputs to MNTB neurons in both WT mice and a fragile X syndrome (FXS) mouse model (both sexes) in which the fragile X mental retardation gene 1 is knocked out (Fmr1 KO), causing exaggerated activity of mGluR I and behavioral phenotypes. Activation of mGluR I by (RS)-3,5-dihydroxyphenylglycine (3,5-DHPG) increased the frequency and amplitude of glycinergic spontaneous IPSCs (sIPSCs) in both WT and Fmr1 KO neurons in a voltage-gated sodium channel-dependent fashion, but did not modulate glycinergic evoked IPSCs (eIPSCs). In contrast, 3,5-DHPG did not affect GABAergic sIPSCs, but did suppress eIPSCs in WT neurons via endocannabinoid signaling. In the KO, the effect of 3,5-DHPG on GABAergic eIPSCs was highly variable, which supports the notion of impaired GABAergic signaling in the FXS model. The differential modulation of sIPSC and eIPSC and differential modulation of glycinergic and GABAergic transmission suggest distinct mechanisms responsible for spontaneous and evoked release of inhibitory transmitters and their modulation through the mGluR I signaling pathway.SIGNIFICANCE STATEMENT Neurons communicate with each other through the release of neurotransmitters, which assumes two basic modes, spontaneous and evoked release. These two release modes are believed to function using the same vesicle pool and machinery. Recent works have challenged this dogma, pointing to distinct vesicle release mechanisms underlying the two release modes. Here, we provide the first evidence in the central auditory system supporting this novel concept. We discovered neural-transmitter- and release-mode-specific neuromodulation of inhibitory transmission by metabotropic glutamate receptors and revealed part of the signaling pathways underlying this differential modulation. The results establish the foundation for a multitude of directions to study physiological significance of different release modes in auditory processing.
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Valdés-Baizabal C, Parras GG, Ayala YA, Malmierca MS. Endocannabinoid Modulation of Stimulus-Specific Adaptation in Inferior Colliculus Neurons of the Rat. Sci Rep 2017; 7:6997. [PMID: 28765608 PMCID: PMC5539202 DOI: 10.1038/s41598-017-07460-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 06/26/2017] [Indexed: 11/11/2022] Open
Abstract
Cannabinoid receptors (CBRs) are widely distributed in the brain, including the inferior colliculus (IC). Here, we aim to study whether endocannabinoids influence a specific type of neuronal adaptation, namely, stimulus-specific adaptation (SSA) found in some IC neurons. SSA is important because it has been found as early as the level of the midbrain and therefore it may be a neuronal correlate of early indices of deviance detection. Furthermore, recent studies have demonstrated a direct link between SSA and MMN, that is widely used as an outcome measure in a variety of human neurodegenerative disorders. SSA is considered a form of short-term plasticity, and CBRs have been shown to play a role in short-term neural plasticity. Therefore, it is reasonable to hypothesize that endocannabinoids may play a role in the generation or modulation of SSA. We recorded single units in the IC under an oddball paradigm stimulation. The results demonstrate that cannabinoid agonists lead to a reduction in the neuronal adaptation. This change is due to a differential increase of the neuronal firing rate to the standard tone alone. Furthermore, we show that the effect is mediated by the cannabinoid receptor 1 (CBR1). Thus, cannabinoid agonists down-modulate SSA in IC neurons.
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Affiliation(s)
- C Valdés-Baizabal
- Auditory Neuroscience Laboratory, Institute of Neuroscience of Castilla y León, Calle Pintor Fernando Gallego 1, 37007, Salamanca, Spain.,The Salamanca Institute for Biomedical Research (IBSAL), 37007, Salamanca, Spain
| | - G G Parras
- Auditory Neuroscience Laboratory, Institute of Neuroscience of Castilla y León, Calle Pintor Fernando Gallego 1, 37007, Salamanca, Spain.,The Salamanca Institute for Biomedical Research (IBSAL), 37007, Salamanca, Spain
| | - Y A Ayala
- Auditory Neuroscience Laboratory, Institute of Neuroscience of Castilla y León, Calle Pintor Fernando Gallego 1, 37007, Salamanca, Spain.,Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, Mexico
| | - M S Malmierca
- Auditory Neuroscience Laboratory, Institute of Neuroscience of Castilla y León, Calle Pintor Fernando Gallego 1, 37007, Salamanca, Spain. .,The Salamanca Institute for Biomedical Research (IBSAL), 37007, Salamanca, Spain. .,Department of Biology and Pathology, Faculty of Medicine, Campus Miguel de Unamuno, University of Salamanca, 37007, Salamanca, Spain.
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6
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Canazza I, Ossato A, Vincenzi F, Gregori A, Di Rosa F, Nigro F, Rimessi A, Pinton P, Varani K, Borea PA, Marti M. Pharmaco-toxicological effects of the novel third-generation fluorinate synthetic cannabinoids, 5F-ADBINACA, AB-FUBINACA, and STS-135 in mice. In vitro and in vivo studies. Hum Psychopharmacol 2017; 32. [PMID: 28597570 DOI: 10.1002/hup.2601] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 04/10/2017] [Accepted: 04/11/2017] [Indexed: 01/08/2023]
Abstract
INTRODUCTION 5F-ADBINACA, AB-FUBINACA, and STS-135 are 3 novel third-generation fluorinate synthetic cannabinoids that are illegally marketed as incense, herbal preparations, or research chemicals for their psychoactive cannabis-like effects. METHODS The present study aims at investigating the in vitro and in vivo pharmacological activity of 5F-ADBINACA, AB-FUBINACA, and STS-135 in male CD-1 mice, comparing their in vivo effects with those caused by the administration of Δ9 -THC and JWH-018. In vitro competition binding experiments revealed a nanomolar affinity and potency of the 5F-ADBINACA, AB-FUBINACA, and STS-135 on mouse and human CB1 and CB2 receptors. Moreover, these synthetic cannabinoids induced neurotoxicity in murine neuro-2a cells. RESULTS In vivo studies showed that 5F-ADBINACA, AB-FUBINACA, and STS-135 induced hypothermia; increased pain threshold to both noxious mechanical and thermal stimuli; caused catalepsy; reduced motor activity; impaired sensorimotor responses (visual, acoustic, and tactile); caused seizures, myoclonia, and hyperreflexia; and promoted aggressiveness in mice. Behavioral and neurological effects were fully prevented by the selective CB1 receptor antagonist/inverse agonist AM 251. Differently, the visual sensory response induced by STS-135 was only partly prevented by the AM 251, suggesting a CB1 -independent mechanism. CONCLUSIONS For the first time, the present study demonstrates the pharmaco-toxicological effects induced by the administration of 5F-ADBINACA, AB-FUBINACA, and STS-135 in mice and suggests their possible detrimental effects on human health.
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Affiliation(s)
- Isabella Canazza
- Department of Life Sciences and Biotechnology (SVeB), University of Ferrara, Ferrara, Italy.,Institute of Public Health, Section of Legal Medicine, Catholic University of Rome, Rome, Italy
| | - Andrea Ossato
- Department of Life Sciences and Biotechnology (SVeB), University of Ferrara, Ferrara, Italy.,Institute of Public Health, Section of Legal Medicine, Catholic University of Rome, Rome, Italy
| | - Fabrizio Vincenzi
- Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Adolfo Gregori
- Carabinieri, Department of Scientific Investigation (RIS), Rome, Italy
| | - Fabiana Di Rosa
- Carabinieri, Department of Scientific Investigation (RIS), Rome, Italy
| | - Federica Nigro
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Alessandro Rimessi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Paolo Pinton
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Katia Varani
- Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Pier Andrea Borea
- Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Matteo Marti
- Department of Life Sciences and Biotechnology (SVeB), University of Ferrara, Ferrara, Italy.,Center for Neuroscience and Istituto Nazionale di Neuroscienze, University of Ferrara, Ferrara, Italy
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7
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Context-Dependent Modulation of Excitatory Synaptic Strength by Synaptically Released Zinc. eNeuro 2017; 4:eN-NWR-0011-17. [PMID: 28275718 PMCID: PMC5334633 DOI: 10.1523/eneuro.0011-17.2017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 02/07/2017] [Accepted: 02/09/2017] [Indexed: 12/12/2022] Open
Abstract
Synaptically released zinc inhibits baseline excitatory neurotransmission; however, the role of this neuromodulator on short-term plasticity during different levels of synaptic activity remains largely unknown. This lack of knowledge prevents our understanding of information transfer across zinc-releasing synapses, including 50% of excitatory synapses in cortical areas. We used in vitro electrophysiology in mouse brain slices and discovered that the effects of zinc on excitatory postsynaptic current (EPSC) amplitudes are context-dependent. At lower frequencies of activity, synaptically released zinc reduces EPSC amplitudes. In contrast, at higher stimulation frequencies and vesicular release probability (Pr), zinc inhibits EPSC amplitudes during the first few stimuli but leads to enhanced steady-state EPSC amplitudes during subsequent stimuli. This paradoxical enhancement is due to zinc-dependent potentiation of synaptic facilitation via the recruitment of endocannabinoid signaling. Together, these findings demonstrate that synaptically released zinc is a modulator of excitatory short-term plasticity, which shapes information transfer among excitatory synapses.
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8
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Yang S, Ben-Shalom R, Ahn M, Liptak AT, van Rijn RM, Whistler JL, Bender KJ. β-Arrestin-Dependent Dopaminergic Regulation of Calcium Channel Activity in the Axon Initial Segment. Cell Rep 2016; 16:1518-1526. [PMID: 27452469 DOI: 10.1016/j.celrep.2016.06.098] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 05/27/2016] [Accepted: 06/29/2016] [Indexed: 11/26/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) initiate a variety of signaling cascades, depending on effector coupling. β-arrestins, which were initially characterized by their ability to "arrest" GPCR signaling by uncoupling receptor and G protein, have recently emerged as important signaling effectors for GPCRs. β-arrestins engage signaling pathways that are distinct from those mediated by G protein. As such, arrestin-dependent signaling can play a unique role in regulating cell function, but whether neuromodulatory GPCRs utilize β-arrestin-dependent signaling to regulate neuronal excitability remains unclear. Here, we find that D3 dopamine receptors (D3R) regulate axon initial segment (AIS) excitability through β-arrestin-dependent signaling, modifying CaV3 voltage dependence to suppress high-frequency action potential generation. This non-canonical D3R signaling thereby gates AIS excitability via pathways distinct from classical GPCR signaling pathways.
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Affiliation(s)
- Sungchil Yang
- Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA; Alcohol and Addiction Research Group, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Roy Ben-Shalom
- Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA; Alcohol and Addiction Research Group, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Misol Ahn
- Department of Pathology and Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Alayna T Liptak
- Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA; Alcohol and Addiction Research Group, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Richard M van Rijn
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA
| | - Jennifer L Whistler
- Alcohol and Addiction Research Group, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Kevin J Bender
- Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA; Alcohol and Addiction Research Group, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA.
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9
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Ossato A, Canazza I, Trapella C, Vincenzi F, De Luca MA, Rimondo C, Varani K, Borea PA, Serpelloni G, Marti M. Effect of JWH-250, JWH-073 and their interaction on "tetrad", sensorimotor, neurological and neurochemical responses in mice. Prog Neuropsychopharmacol Biol Psychiatry 2016; 67:31-50. [PMID: 26780169 DOI: 10.1016/j.pnpbp.2016.01.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 01/12/2016] [Accepted: 01/13/2016] [Indexed: 10/22/2022]
Abstract
JWH-250 and JWH-073 are two synthetic cannabinoid agonists with nanomolar affinity at CB1 and CB2 receptors. They are illegally marketed within "herbal blend" for theirs psychoactive effects greater than those produced by Cannabis. Recently, we analyzed an "herbal" preparation containing a mixture of both JWH-250 and JWH-073. The present study was aimed at investigating the in vitro and in vivo pharmacological activity of JWH-250 and JWH-073 in male CD-1 mice. In vitro competition binding experiments performed on mouse and human CB1 and CB2 receptors revealed a nanomolar affinity and potency of the JWH-250 and JWH-073. In vivo studies showed that JWH-250 and JWH-073, administered separately, induced a marked hypothermia, increased pain threshold to both noxious mechanical and thermal stimuli, caused catalepsy, reduced motor activity, impaired sensorimotor responses (visual, acoustic and tactile), caused seizures, myoclonia, hyperreflexia and promote aggressiveness in mice. Moreover, microdialysis study in freely moving mice showed that systemic administration of JWH-250 and JWH-073 stimulated dopamine release in the nucleus accumbens in a dose-dependent manner. Behavioral, neurological and neurochemical effects were fully prevented by the selective CB1 receptor antagonist/inverse agonist AM 251. Co-administration of ineffective doses of JWH-250 and JWH-073 impaired visual sensorimotor responses, improved mechanical pain threshold and stimulated mesolimbic DA transmission in mice, living unchanged all other behavioral and physiological parameters. For the first time the present study demonstrates the overall pharmacological effects induced by the administration of JWH-250 and JWH-073 in mice and it reveals their potentially synergistic action suggesting that co-administration of different synthetic cannabinoids may potentiate the detrimental effects of individual compounds increasing their dangerousness and abuse potential.
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Affiliation(s)
- Andrea Ossato
- Department of Life Sciences and Biotechnology (SVeB), University of Ferrara, Italy
| | - Isabella Canazza
- Department of Life Sciences and Biotechnology (SVeB), University of Ferrara, Italy
| | - Claudio Trapella
- Department of Chemistry and Pharmaceutical Sciences, University of Ferrara, Italy
| | | | | | - Claudia Rimondo
- Department of Public Health and Community Medicine, University of Verona, Italy
| | - Katia Varani
- Department of Medical Sciences, University of Ferrara, Italy
| | | | - Giovanni Serpelloni
- Department of Neuroscience, Psychology, Medicine and Child Health (NEUROFARBA), University of Florence, Italy
| | - Matteo Marti
- Department of Life Sciences and Biotechnology (SVeB), University of Ferrara, Italy; Center for Neuroscience and Istituto Nazionale di Neuroscienze, Italy.
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Smith PF, Zheng Y. Cannabinoids, cannabinoid receptors and tinnitus. Hear Res 2015; 332:210-216. [PMID: 26433054 DOI: 10.1016/j.heares.2015.09.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 09/03/2015] [Accepted: 09/24/2015] [Indexed: 12/29/2022]
Abstract
One hypothesis suggests that tinnitus is a form of sensory epilepsy, arising partly from neuronal hyperactivity in auditory regions of the brain such as the cochlear nucleus and inferior colliculus. Although there is currently no effective drug treatment for tinnitus, anti-epileptic drugs are used in some cases as a potential treatment option. There is increasing evidence to suggest that cannabinoid drugs, i.e. cannabinoid receptor agonists, can also have anti-epileptic effects, at least in some cases and in some parts of the brain. It has been reported that cannabinoid CB1 receptors and the endogenous cannabinoid, 2-arachidonylglycerol (2-AG), are expressed in the cochlear nucleus and that they are involved in the regulation of plasticity. This review explores the question of whether cannabinoid receptor agonists are likely to be pro- or anti-epileptic in the cochlear nucleus and therefore whether cannabinoids and Cannabis itself are likely to make tinnitus better or worse.
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Affiliation(s)
- Paul F Smith
- Dept. of Pharmacology and Toxicology, School of Medical Sciences, University of Otago Medical School, Dunedin, New Zealand.
| | - Yiwen Zheng
- Dept. of Pharmacology and Toxicology, School of Medical Sciences, University of Otago Medical School, Dunedin, New Zealand
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11
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Wu C, Martel DT, Shore SE. Transcutaneous induction of stimulus-timing-dependent plasticity in dorsal cochlear nucleus. Front Syst Neurosci 2015; 9:116. [PMID: 26321928 PMCID: PMC4536405 DOI: 10.3389/fnsys.2015.00116] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 07/30/2015] [Indexed: 11/13/2022] Open
Abstract
The cochlear nucleus (CN) is the first site of multisensory integration in the ascending auditory pathway. The principal output neurons of the dorsal cochlear nucleus (DCN), fusiform cells, receive somatosensory information relayed by the CN granule cells from the trigeminal and dorsal column pathways. Integration of somatosensory and auditory inputs results in long-term enhancement or suppression in a stimulus-timing-dependent manner. Here, we demonstrate that stimulus-timing-dependent plasticity (STDP) can be induced in DCN fusiform cells using paired auditory and transcutaneous electrical stimulation of the face and neck to activate trigeminal and dorsal column pathways to the CN, respectively. Long-lasting changes in fusiform cell firing rates persisted for up to 2 h after this bimodal stimulation, and followed Hebbian or anti-Hebbian rules, depending on tone duration, but not somatosensory stimulation location: 50 ms paired tones evoked predominantly Hebbian, while 10 ms paired tones evoked predominantly anti-Hebbian plasticity. The tone-duration-dependent STDP was strongly correlated with first inter-spike intervals, implicating intrinsic cellular properties as determinants of STDP. This study demonstrates that transcutaneous stimulation with precise auditory-somatosensory timing parameters can non-invasively induce fusiform cell long-term modulation, which could be harnessed in the future to moderate tinnitus-related hyperactivity in DCN.
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Affiliation(s)
- Calvin Wu
- Kresge Hearing Research Institute-Department of Otolaryngology, University of Michigan Ann Arbor, MI, USA
| | - David T Martel
- Kresge Hearing Research Institute-Department of Otolaryngology, University of Michigan Ann Arbor, MI, USA ; Department of Biomedical Engineering, University of Michigan Ann Arbor, MI, USA
| | - Susan E Shore
- Kresge Hearing Research Institute-Department of Otolaryngology, University of Michigan Ann Arbor, MI, USA ; Department of Biomedical Engineering, University of Michigan Ann Arbor, MI, USA ; Department of Molecular and Integrative Physiology, University of Michigan Ann Arbor, MI, USA
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12
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Ossato A, Vigolo A, Trapella C, Seri C, Rimondo C, Serpelloni G, Marti M. JWH-018 impairs sensorimotor functions in mice. Neuroscience 2015; 300:174-88. [PMID: 25987201 DOI: 10.1016/j.neuroscience.2015.05.021] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 05/04/2015] [Accepted: 05/09/2015] [Indexed: 02/01/2023]
Abstract
Naphthalen-1-yl-(1-pentylindol-3-yl)methanone (JWH-018) is a synthetic cannabinoid agonist illegally marketed in "Spice" and "herbal blend" for its psychoactive effect greater than those produced by cannabis. In rodents JWH-018 reproduces typical effects of (-)-Δ(9)-THC or Dronabinol® (Δ(9)-THC) such as hypothermia, analgesia, hypolocomotion and akinesia, while its effects on sensorimotor functions are still unknown. Therefore, the aim of the present study is to investigate the effect of acute administration of JWH-018 (0.01-6mg/kg i.p.) on sensorimotor functions in male CD-1 mice and to compare its effects with those caused by the administration of Δ(9)-THC (0.01-6mg/kg i.p.). A specific battery of behavioral tests were adopted to investigate effects of cannabinoid agonists on sensorimotor functions (visual, auditory, tactile) and neurological changes (convulsion, myoclonia, hyperreflexia) while video-tracking analysis was used to study spontaneous locomotion. JWH-018 administration inhibited sensorimotor responses at lower doses (0.01-0.1mg/kg), reduced spontaneous locomotion at intermediate/high doses (1-6mg/kg) and induced convulsions, myoclonia and hyperreflexia at high doses (6mg/kg). Similarly, administration of Δ(9)-THC reduced sensorimotor responses in mice but it did not inhibit spontaneous locomotion and it did not induce neurological alterations. All behavioral effects and neurological alterations were prevented by the administration of the selective CB1 receptor antagonist/inverse agonist 1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-(piperidin-1-yl)-1H-pyrazole-3-carboxamide (AM 251). For the first time these data demonstrate that JWH-018 impairs sensorimotor responses in mice. This aspect should be carefully evaluated to better understand the potential danger that JWH-018 may pose to public health, with particular reference to decreased performance in driving and hazardous works.
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Affiliation(s)
- A Ossato
- Department of Life Sciences and Biotechnology (SVeB), University of Ferrara, Italy
| | - A Vigolo
- Department of Life Sciences and Biotechnology (SVeB), University of Ferrara, Italy
| | - C Trapella
- Department of Chemistry and Pharmaceutical Sciences, University of Ferrara, Italy
| | - C Seri
- Italian National Early Warning System, Drug Policies Department, Presidency of the Council of Ministers, Verona Coordination Unit, Italy
| | - C Rimondo
- Italian National Early Warning System, Drug Policies Department, Presidency of the Council of Ministers, Verona Coordination Unit, Italy; Department of Public Health and Community Medicine, University of Verona, Italy
| | - G Serpelloni
- Italian National Early Warning System, Drug Policies Department, Presidency of the Council of Ministers, Verona Coordination Unit, Italy
| | - M Marti
- Department of Life Sciences and Biotechnology (SVeB), University of Ferrara, Italy; Center for Neuroscience and Istituto Nazionale di Neuroscienze, Italy.
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13
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Synaptic plasticity in the auditory system: a review. Cell Tissue Res 2015; 361:177-213. [PMID: 25896885 DOI: 10.1007/s00441-015-2176-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 03/18/2015] [Indexed: 01/19/2023]
Abstract
Synaptic transmission via chemical synapses is dynamic, i.e., the strength of postsynaptic responses may change considerably in response to repeated synaptic activation. Synaptic strength is increased during facilitation, augmentation and potentiation, whereas a decrease in synaptic strength is characteristic for depression and attenuation. This review attempts to discuss the literature on short-term and long-term synaptic plasticity in the auditory brainstem of mammals and birds. One hallmark of the auditory system, particularly the inner ear and lower brainstem stations, is information transfer through neurons that fire action potentials at very high frequency, thereby activating synapses >500 times per second. Some auditory synapses display morphological specializations of the presynaptic terminals, e.g., calyceal extensions, whereas other auditory synapses do not. The review focuses on short-term depression and short-term facilitation, i.e., plastic changes with durations in the millisecond range. Other types of short-term synaptic plasticity, e.g., posttetanic potentiation and depolarization-induced suppression of excitation, will be discussed much more briefly. The same holds true for subtypes of long-term plasticity, like prolonged depolarizations and spike-time-dependent plasticity. We also address forms of plasticity in the auditory brainstem that do not comprise synaptic plasticity in a strict sense, namely short-term suppression, paired tone facilitation, short-term adaptation, synaptic adaptation and neural adaptation. Finally, we perform a meta-analysis of 61 studies in which short-term depression (STD) in the auditory system is opposed to short-term depression at non-auditory synapses in order to compare high-frequency neurons with those that fire action potentials at a lower rate. This meta-analysis reveals considerably less STD in most auditory synapses than in non-auditory ones, enabling reliable, failure-free synaptic transmission even at frequencies >100 Hz. Surprisingly, the calyx of Held, arguably the best-investigated synapse in the central nervous system, depresses most robustly. It will be exciting to reveal the molecular mechanisms that set high-fidelity synapses apart from other synapses that function much less reliably.
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Zheng Y, Reid P, Smith PF. Cannabinoid CB1 Receptor Agonists Do Not Decrease, but may Increase Acoustic Trauma-Induced Tinnitus in Rats. Front Neurol 2015; 6:60. [PMID: 25852639 PMCID: PMC4364172 DOI: 10.3389/fneur.2015.00060] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 03/05/2015] [Indexed: 11/13/2022] Open
Abstract
Tinnitus has been suggested to arise from neuronal hyperactivity in auditory areas of the brain, and anti-epileptic drugs are sometimes used to provide relief from tinnitus. Recently, the anti-epileptic properties of the cannabinoid drugs have gained increasing interest; however, the use of cannabinoids as a form of treatment for tinnitus is controversial. In this study, we tested whether a combination of delta-9-tetrahydrocannabinol (delta-9-THC) and cannabidiol (CBD), delivered in a 1:1 ratio, could affect tinnitus perception in a rat model of acoustic trauma-induced tinnitus. Following sham treatment or acoustic trauma, the animals were divided into the following groups: (1) sham (i.e., no acoustic trauma) with vehicle treatment; (2) sham with drug treatment (i.e., delta-9-THC + CBD); (3) acoustic trauma-exposed exhibiting tinnitus, with drug treatment; and (4) acoustic trauma-exposed exhibiting no tinnitus, with drug treatment. The animals received either the vehicle or the cannabinoid drugs every day, 30 min before the tinnitus behavioral testing. Acoustic trauma caused a significant increase in the auditory brainstem response (ABR) thresholds in the exposed animals, indicating hearing loss; however, there was a partial recovery over 6 months. Acoustic trauma did not always result in tinnitus; however, among those that did exhibit tinnitus, some of them had tinnitus at multiple frequencies while others had it only at a single frequency. The cannabinoids significantly increased the number of tinnitus animals in the exposed-tinnitus group, but not in the sham group. The results suggest that cannabinoids may promote the development of tinnitus, especially when there is pre-existing hearing damage.
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Affiliation(s)
- Yiwen Zheng
- Department of Pharmacology and Toxicology, School of Medical Sciences, University of Otago , Dunedin , New Zealand ; Brain Health Research Centre, School of Medical Sciences, University of Otago , Dunedin , New Zealand
| | - Peter Reid
- Department of Pharmacology and Toxicology, School of Medical Sciences, University of Otago , Dunedin , New Zealand ; Brain Health Research Centre, School of Medical Sciences, University of Otago , Dunedin , New Zealand
| | - Paul F Smith
- Department of Pharmacology and Toxicology, School of Medical Sciences, University of Otago , Dunedin , New Zealand ; Brain Health Research Centre, School of Medical Sciences, University of Otago , Dunedin , New Zealand
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15
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He S, Wang YX, Petralia RS, Brenowitz SD. Cholinergic modulation of large-conductance calcium-activated potassium channels regulates synaptic strength and spine calcium in cartwheel cells of the dorsal cochlear nucleus. J Neurosci 2014; 34:5261-72. [PMID: 24719104 PMCID: PMC3983802 DOI: 10.1523/jneurosci.3728-13.2014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 02/05/2014] [Accepted: 03/11/2014] [Indexed: 11/21/2022] Open
Abstract
Acetylcholine is a neuromodulatory transmitter that controls synaptic plasticity and sensory processing in many brain regions. The dorsal cochlear nucleus (DCN) is an auditory brainstem nucleus that integrates auditory signals from the cochlea with multisensory inputs from several brainstem nuclei and receives prominent cholinergic projections. In the auditory periphery, cholinergic modulation serves a neuroprotective function, reducing cochlear output under high sound levels. However, the role of cholinergic signaling in the DCN is less understood. Here we examine postsynaptic mechanisms of cholinergic modulation at glutamatergic synapses formed by parallel fiber axons onto cartwheel cells (CWCs) in the apical DCN circuit from mouse brainstem slice using calcium (Ca) imaging combined with two-photon laser glutamate uncaging onto CWC spines. Activation of muscarinic acetylcholine receptors (mAChRs) significantly increased the amplitude of both uncaging-evoked EPSPs (uEPSPs) and spine Ca transients. Our results demonstrate that mAChRs in CWC spines act by suppressing large-conductance calcium-activated potassium (BK) channels, and this effect is mediated through the cAMP/protein kinase A signaling pathway. Blocking BK channels relieves voltage-dependent magnesium block of NMDA receptors, thereby enhancing uEPSPs and spine Ca transients. Finally, we demonstrate that mAChR activation inhibits L-type Ca channels and thus may contribute to the suppression of BK channels by mAChRs. In summary, we demonstrate a novel role for BK channels in regulating glutamatergic transmission and show that this mechanism is under modulatory control of mAChRs.
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Affiliation(s)
- Shan He
- Section on Synaptic Transmission and
| | - Ya-Xian Wang
- Advanced Imaging Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland 20892
| | - Ronald S. Petralia
- Advanced Imaging Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland 20892
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16
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Greenwood LM, Broyd SJ, Croft R, Todd J, Michie PT, Johnstone S, Murray R, Solowij N. Chronic effects of cannabis use on the auditory mismatch negativity. Biol Psychiatry 2014; 75:449-58. [PMID: 23830666 DOI: 10.1016/j.biopsych.2013.05.035] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 05/26/2013] [Accepted: 05/30/2013] [Indexed: 01/01/2023]
Abstract
BACKGROUND Cannabis use is associated with the development of psychotic symptoms and increased risk for schizophrenia. The mismatch negativity (MMN) is a brain event-related potential marker of change detection thought to index glutamatergic N-methyl-D-aspartate receptor-mediated neurotransmission, which is known to be deficient in schizophrenia. This study examined auditory MMN in otherwise healthy chronic cannabis users compared with nonuser control subjects. METHODS Forty-two chronic cannabis users and 44 nonuser healthy control subjects completed a multi-feature MMN paradigm, which included duration, frequency, and intensity deviants (deviants 6%; standards 82%). The MMN was compared between users and control subjects as well as between long- and short-term users and age- and gender-matched control subjects. Associations between MMN, cannabis use measures, and symptoms were examined. RESULTS The MMN amplitude was significantly reduced to frequency but not duration or intensity deviants in overall cannabis users relative to control subjects. Frequency MMN was similarly attenuated in short- and long-term users relative to control subjects. Long-term users also exhibited reduced duration MMN relative to control subjects and short-term users and this was correlated with increased duration of exposure to cannabis and increased psychotic-like experiences during intoxication. In short-term users, a younger age of onset of regular cannabis use and greater frequency of use were associated with greater psychotic-like experiences and symptomatic distress. CONCLUSIONS These results suggest impaired sensory memory that might reflect N-methyl-D-aspartate receptor dysfunction in chronic cannabis users. The pattern of MMN alterations in cannabis users differed from that typically observed in patients with schizophrenia, indicating overlapping but distinct underlying pathology.
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Affiliation(s)
- Lisa-Marie Greenwood
- School of Psychology and ψ-P3: Centre for Psychophysics, Psychophysiology and Psychopharmacology, University of Wollongong, Wollongong
| | - Samantha J Broyd
- School of Psychology and ψ-P3: Centre for Psychophysics, Psychophysiology and Psychopharmacology, University of Wollongong, Wollongong
| | - Rodney Croft
- School of Psychology and ψ-P3: Centre for Psychophysics, Psychophysiology and Psychopharmacology, University of Wollongong, Wollongong
| | - Juanita Todd
- School of Psychology and Priority Research Centre for Translational Neuroscience and Mental Health, University of Newcastle, Newcastle; Schizophrenia Research Institute, Sydney, New South Wales, Australia
| | - Patricia T Michie
- School of Psychology and Priority Research Centre for Translational Neuroscience and Mental Health, University of Newcastle, Newcastle; Schizophrenia Research Institute, Sydney, New South Wales, Australia
| | - Stuart Johnstone
- School of Psychology and ψ-P3: Centre for Psychophysics, Psychophysiology and Psychopharmacology, University of Wollongong, Wollongong
| | - Robin Murray
- Institute of Psychiatry, Kings College, London, United Kingdom
| | - Nadia Solowij
- School of Psychology and ψ-P3: Centre for Psychophysics, Psychophysiology and Psychopharmacology, University of Wollongong, Wollongong; Schizophrenia Research Institute, Sydney, New South Wales, Australia.
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CA1 pyramidal cell theta-burst firing triggers endocannabinoid-mediated long-term depression at both somatic and dendritic inhibitory synapses. J Neurosci 2013; 33:13743-57. [PMID: 23966696 DOI: 10.1523/jneurosci.0817-13.2013] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Endocannabinoids (eCBs) are retrograde lipid messengers that, by targeting presynaptic type 1 cannabinoid receptors (CB1Rs), mediate short- and long-term synaptic depression of neurotransmitter release throughout the brain. Short-term depression is typically triggered by postsynaptic, depolarization-induced calcium rises, whereas long-term depression is induced by synaptic activation of Gq/11 protein-coupled receptors. Here we report that a physiologically relevant pattern of postsynaptic activity, in the form of theta-burst firing (TBF) of hippocampal CA1 pyramidal neurons, can trigger long-term depression of inhibitory transmission (iLTD) in rat hippocampal slices. Paired recordings between CA1 interneurons and pyramidal cells, followed by post hoc morphological reconstructions of the interneurons' axon, revealed that somatic and dendritic inhibitory synaptic inputs equally expressed TBF-induced iLTD. Simultaneous recordings from neighboring pyramidal cells demonstrated that eCB signaling triggered by TBF was highly restricted to only a single, active cell. Furthermore, pairing submaximal endogenous activation of metabotropic glutamate or muscarinic acetylcholine receptors with submaximal TBF unmasked associative iLTD. Although CB1Rs are also expressed at Schaffer-collateral excitatory terminals, long-term plasticity under various recording conditions was spared at these synapses. Consistent with this observation, TBF also shifted the balance of excitation and inhibition in favor of excitatory throughput, thereby altering information flow through the CA1 circuit. Given the near ubiquity of burst-firing activity patterns and CB1R expression in the brain, the properties described here may be a general means by which neurons fine tune the strength of their inputs in a cell-wide and cell-specific manner.
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18
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Trattner B, Berner S, Grothe B, Kunz L. Depolarization-induced suppression of a glycinergic synapse in the superior olivary complex by endocannabinoids. J Neurochem 2013; 127:78-90. [PMID: 23859596 DOI: 10.1111/jnc.12369] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Revised: 07/09/2013] [Accepted: 07/09/2013] [Indexed: 11/27/2022]
Abstract
The neuronal endocannabinoid system is known to depress synaptic inputs retrogradely in an activity-dependent manner. This mechanism has been generally described for excitatory glutamatergic and inhibitory GABAergic synapses. Here, we report that neurones in the auditory brainstem of the Mongolian gerbil (Meriones unguiculatus) retrogradely regulate the strength of their inputs via the endocannabinoid system. By means of whole-cell patch-clamp recordings, we found that retrograde endocannabinoid signalling attenuates both glycinergic and glutamatergic post-synaptic currents in the same types of neurones. Accordingly, we detected the cannabinoid receptor 1 in excitatory and inhibitory pre-synapses as well as the endocannabinoid-synthesising enzymes (diacylglycerol lipase α/β, DAGLα/β) post-synaptically through immunohistochemical stainings. Our study was performed with animals aged 10-15 days, that is, in the time window around the onset of hearing. Therefore, we suggest that retrograde endocannabinoid signalling has a role in adapting inputs during the functionally important switch from spontaneously generated to sound-related signals.
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Affiliation(s)
- Barbara Trattner
- Department of Biology II, Division of Neurobiology, Ludwig Maximilians University Munich, Martinsried, Germany; Graduate School of Systemic Neurosciences, Ludwig Maximilians University Munich, Martinsried, Germany
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19
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Abstract
Although it is well established that many glutamatergic neurons sequester Zn(2+) within their synaptic vesicles, the physiological significance of synaptic Zn(2+) remains poorly understood. In experiments performed in a Zn(2+)-enriched auditory brainstem nucleus--the dorsal cochlear nucleus--we discovered that synaptic Zn(2+) and GPR39, a putative metabotropic Zn(2+)-sensing receptor (mZnR), are necessary for triggering the synthesis of the endocannabinoid 2-arachidonoylglycerol (2-AG). The postsynaptic production of 2-AG, in turn, inhibits presynaptic probability of neurotransmitter release, thus shaping synaptic strength and short-term synaptic plasticity. Zn(2+)-induced inhibition of transmitter release is absent in mutant mice that lack either vesicular Zn(2+) or the mZnR. Moreover, mass spectrometry measurements of 2-AG levels reveal that Zn(2+)-mediated initiation of 2-AG synthesis is absent in mice lacking the mZnR. We reveal a previously unknown action of synaptic Zn(2+): synaptic Zn(2+) inhibits glutamate release by promoting 2-AG synthesis.
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20
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Koehler SD, Shore SE. Stimulus-timing dependent multisensory plasticity in the guinea pig dorsal cochlear nucleus. PLoS One 2013; 8:e59828. [PMID: 23527274 PMCID: PMC3603886 DOI: 10.1371/journal.pone.0059828] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 02/19/2013] [Indexed: 11/19/2022] Open
Abstract
Multisensory neurons in the dorsal cochlear nucleus (DCN) show long-lasting enhancement or suppression of sound-evoked responses when stimulated with combined somatosensory-auditory stimulation. By varying the intervals between sound and somatosensory stimuli we show for the first time in vivo that DCN bimodal responses are influenced by stimulus-timing dependent plasticity. The timing rules and time courses of the observed stimulus-timing dependent plasticity closely mimic those of spike-timing dependent plasticity that have been demonstrated in vitro at parallel-fiber synapses onto DCN principal cells. Furthermore, the degree of inhibition in a neuron influences whether that neuron has Hebbian or anti-Hebbian timing rules. As demonstrated in other cerebellar-like circuits, anti-Hebbian timing rules reflect adaptive filtering, which in the DCN would result in suppression of sound-evoked responses that are predicted by activation of somatosensory inputs, leading to the suppression of body-generated signals such as self-vocalization.
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Affiliation(s)
- Seth D. Koehler
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Susan E. Shore
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- Department of Molecular and Integrative Physiology, University of Michigan Medical School Ann Arbor, Michigan, United States of America
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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