title: Role of TRPV1 receptors on panic-like behaviors mediated by the dorsolateral periaqueductal gray in rats.
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.
authors.affiliation: Department of Pharmacology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Av. Pres. Antônio Carlos 6627, 31270-901, Belo Horizonte, MG, Brazil.
authors.forename: A F
authors.initials: AF
authors.lastname: Almeida-Santos
authors.forename: F A
authors.initials: FA
authors.lastname: Moreira
authors.forename: F S
authors.initials: FS
authors.lastname: Guimarães
authors.forename: D C
authors.initials: DC
authors.lastname: Aguiar
mesh_terms: D000818:Animals; D008297:Male; D016584:Panic Disorder / Q000503:physiopathology*; D010487:Periaqueductal Gray / Q000503:physiopathology*; D051381:Rats; D017208:Rats, Wistar; D050916:TRPV Cation Channels / Q000502:physiology*
chemical_list: D050916:TRPV Cation Channels; C494484:TRPV1 receptor