Capsaicin- and anandamide-induced gastric acid secretion via vanilloid receptor type 1 (TRPV1) in rat brain.
The activation of transient receptor potential vanilloid receptor 1 (TRPV1) by capsaicin in rat brain stimulates gastric acid secretion via tachykinin NK2 receptors and the vagus cholinergic nerve, but the involvement of other receptor systems has not been elucidated. We investigated the role of the glutamate and gamma-amino-butyric acid (GABA) receptor systems on the capsaicin response. Gastric acid secretion stimulated by the injection of capsaicin (30 nmol) into the lateral cerebroventricle (i.c.v.) was inhibited by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, an antagonist of non-N-methyl-D-aspartate (non-NMDA) receptors, 10.9 nmol, i.c.v.) and bicuculline (a GABA(A) receptor antagonist, 222 microg kg(-1) 10 min(-1), i.v. infusion). Secretion stimulated by the injection of capsaicin (50 nmol) into the fourth cerebroventricle was inhibited by CNQX and bicuculline. I.c.v. injection of anandamide (an endogenous ligand of TRPV1 and cannabinoid receptors, 30 and 100 nmol) stimulated gastric acid secretion, and the response was inhibited by an antagonist of TRPV1 and in the capsaicin-treated rats, but not by an antagonist of cannabinoid receptors. In conclusion, the TRPV1 system, which is activated by capsaicin and anandamide, is preferentially coupled with non-NMDA and GABA(A) receptor systems in the brain and stimulates gastric acid secretion in rats.
Minowa
Sachie
S
Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 260-8675, Japan.
Ishihara
Satomi
S
Tsuchiya
Shizuko
S
Horie
Syunji
S
Murayama
Toshihiko
T
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000818:Animals; D001095:Arachidonic Acids / Q000008:administration & dosage*; D001640:Bicuculline / Q000494:pharmacology; D063385:Cannabinoid Receptor Modulators / Q000008:administration & dosage; D002211:Capsaicin / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D063388:Endocannabinoids; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D005744:Gastric Acid / Q000378:metabolism*; D005753:Gastric Mucosa / Q000187:drug effects / Q000294:innervation; D007276:Injections, Intraventricular; D007473:Ion Channels / Q000187:drug effects* / Q000502:physiology; D008297:Male; D053284:Polyunsaturated Alkamides; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000187:drug effects / Q000502:physiology*; D017470:Receptors, Glutamate / Q000187:drug effects / Q000502:physiology*; D018709:Statistics, Nonparametric; D050916:TRPV Cation Channels
D001095:Arachidonic Acids; D063385:Cannabinoid Receptor Modulators; D063388:Endocannabinoids; D018691:Excitatory Amino Acid Antagonists; D018756:GABA Antagonists; D007473:Ion Channels; D053284:Polyunsaturated Alkamides; D011963:Receptors, GABA-A; D017470:Receptors, Glutamate; D050916:TRPV Cation Channels; C493922:Trpv1 protein, rat; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D002211:Capsaicin; C078814:anandamide; D001640:Bicuculline