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Transient receptor potential vanilloid type 1 receptor regulates glutamatergic synaptic inputs to the spinothalamic tract neurons of the spinal cord deep dorsal horn

Cited 17 time in Web of Science Cited 18 time in Scopus
Authors
Kim, H; Cui, L; Kim, J; Kim, S J
Issue Date
2009-02-25
Publisher
Elsevier
Citation
Neuroscience. 160(2):508-516
Keywords
AnimalsCalcium Channels/metabolismCapsaicin/pharmacologyExcitatory Postsynaptic Potentials/*physiologyFemaleGlutamic Acid/metabolismMaleMiniature Postsynaptic Potentials/physiologyPain/*metabolismPosterior Horn Cells/*metabolismRatsRats, Sprague-DawleySensory System Agents/pharmacologySpinothalamic Tracts/cytology/*metabolismStatistics, NonparametricSynaptic Transmission/*physiologyTRPV Cation Channels/*metabolismgamma-Aminobutyric Acid/metabolism
Abstract
The spinothalamic tract (STT) neurons in the spinal dorsal horn play an important role in transmission and processing of nociceptive sensory information. Although transient receptor potential vanilloid type 1 (TRPV1) receptors are present in the spinal cord dorsal horn, their physiological function is not fully elucidated. In this study, we examined the role of TRPV1 in modulating neuronal activity of the STT neurons through excitatory and inhibitory synaptic inputs. Whole-cell patch-clamp recordings were performed on STT neurons labeled by a retrograde fluorescent tracer injected into the ventral posterior lateral (VPL) nucleus of the thalamus. Capsaicin (1 microM) increased the frequency of miniature excitatory postsynaptic currents (mEPSC) without changing the amplitude or decay time constant of mEPSC. In contrast, capsaicin had no distinct effect on GABAergic miniature inhibitory postsynaptic currents (mIPSC). Capsazepine (10 microM), a TRPV1 receptor antagonist, abolished the effect of capsaicin on mEPSCs. Capsazepine itself did not affect the baseline amplitude and frequency of mEPSC. The effect of capsaicin on mEPSC was also abolished by removal of external Ca(2+), but not by treatment with Cd(2+). Furthermore, capsaicin increased the firing activity of the STT neurons and this increase in neuronal activity by capsaicin was abolished in the presence of non-N-methyl-d-aspartic acid (NMDA) and NMDA receptor antagonists, 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline-2,3-dione (NBQX) and (R)-amino-5-phosphonovaleric acid (APV). These data suggest that activation of TRPV1 potentiates the glutamate release from excitatory terminals of primary afferent fibers and subsequently increases the neural activity of STT neurons of the rat spinal cord deep dorsal horn.
ISSN
1873-7544 (Electronic)
Language
English
URI
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=19236908

http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6T0F-4VNK6C2-1-N&_cdi=4861&_user=168665&_orig=search&_coverDate=05%2F05%2F2009&_sk=998399997&view=c&wchp=dGLzVlz-zSkWz&md5=a7907d5c04c5913dc476e9430febd705&ie=/sdarticle.pdf

http://hdl.handle.net/10371/68131
DOI
https://doi.org/10.1016/j.neuroscience.2009.02.019
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College of Medicine/School of Medicine (의과대학/대학원)Dept. of Physiology (생리학교실)Journal Papers (저널논문_생리학교실)
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