Referenced in: none

Automatically associated channels: TRP , TRPV , TRPV1

Title: Role of TRPV1 receptors on panic-like behaviors mediated by the dorsolateral periaqueductal gray in rats.

Authors: A F Almeida-Santos, F A Moreira, F S Guimarães, D C Aguiar

Journal, date & volume: Pharmacol. Biochem. Behav., 2013 Apr , 105, 166-72

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/23474373

Abstract
The transient receptors potential vanilloid type 1 channels (TRPV1) are expressed in several brain regions related to defensive behaviors, including the dorsolateral periaqueductal gray (dlPAG). The endocannabinoid anandamide, in addition to its agonist activity at cannabinoid type 1 (CB1), is also proposed as an endogenous agonist of these receptors, through which it could facilitate anxiety-like responses. The aim of this work was to test the hypothesis that TRPV1 in the dlPAG of rats would mediate panic-like responses in two models, namely the escape responses induced by chemical stimulation of this structure or by exposure to the elevated T-Maze (ETM). Antagonism of TRPV1 with capsazepine injected into the dlPAG reduced the defense response induced by local NMDA-injection, suggesting an anti-aversive effect. In the ETM, capsazepine inhibited escape response, suggesting a panicolytic-like effect. Interestingly, this effect was prevented by a CB1 antagonist (AM251). The present study showed that antagonism of TRPV1 in the dlPAG induces panicolytic-like effects, which can be prevented by a CB1 antagonist. Therefore, these antiaversive effects of TRPV1 blockade may ultimately occur due to a predominant action of anandamide through CB1 receptors.