Depression of presynaptic excitation by the activation of vanilloid receptor 1 in the rat spinal dorsal horn revealed by optical imaging

Molecular Pain
Kei KusudoK Murase

Abstract

In this study, we show that capsaicin (CAP) depresses primary afferent fiber terminal excitability by acting on vanilloid receptor 1 (TRPV1 channels) of primary afferent fibers in adenosine 5'-triphosphate (ATP)- and temperature-dependent manner using two optical imaging methods. First, transverse slices of spinal cord were stained with a voltage-sensitive dye and the net excitation in the spinal dorsal horn was recorded. Prolonged treatment (>20 min) with the TRPV1 channel agonist, CAP, resulted in a long-lasting inhibition of the net excitation evoked by single-pulse stimulation of C fiber-activating strength. A shorter application of CAP inhibited the excitation in a concentration-dependent manner and the inhibition was reversed within several minutes. This inhibition was Ca(++)-dependent, was antagonized by the TRPV1 channel antagonist, capsazepine (CPZ), and the P(2)X and P(2)Y antagonist, suramin, and was facilitated by the P(2)Y agonist, uridine 5'-triphosphate (UTP). The inhibition of excitation was unaffected by bicuculline and strychnine, antagonists of GABA(A) and glycine receptors, respectively. Raising the perfusate temperature to 39 degrees C from 27 degrees C inhibited the excitation (-3%/ degrees C). This depres...Continue Reading

References

Jul 23, 1993·Neuroscience Letters·L Urban, A Dray
Dec 31, 1997·Nature·D E Clapham
Apr 15, 1999·Annual Review of Neuroscience·A B MacDermottS A Siegelbaum
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Nov 5, 2004·The Journal of Neuroscience : the Official Journal of the Society for Neuroscience·Hiroshi Ikeda, Kazuyuki Murase

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Citations

Feb 15, 2008·Naunyn-Schmiedeberg's Archives of Pharmacology·Laszlo KölesPeter Illes
Aug 21, 2010·Proceedings of the National Academy of Sciences of the United States of America·Yun GuanXinzhong Dong
Jun 4, 2013·Molecular Pain·Alexandra HigginsBrian D Burrell
Feb 18, 2016·Neural Plasticity·Seung-In ChoiSun Wook Hwang
Apr 12, 2007·The European Journal of Neuroscience·Hiroshi IkedaKazuyuki Murase
Feb 24, 2010·Neuroscience Letters·Priscila Elisa SilveiraLígia Araujo Naves

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