Alpha 2-adrenoceptor-mediated inhibitory and excitatory effects of detomidine on rat gastric acid secretion.
The effects of the selective alpha 2-adrenoceptor agonist detomidine on gastric acid secretion from pylorus-ligated and stomach-perfused rats have been investigated. In pylorus-ligated rats i.p. injection of detomidine markedly inhibited acid secretion, this effect being prevented by yohimbine or idazoxan. Under the same conditions, idazoxan significantly increased secretion in a dose-independent fashion. In non-vagotomized and vagotomized stomach-perfused rats i.p. detomidine stimulated acid secretion: this excitatory effect was antagonized by idazoxan. The present results suggest that both inhibitory and excitatory gastric secretory effects of detomidine are mediated by alpha 2-adrenoceptors on cholinergic and adrenergic nerves, respectively. The stimulant activity of idazoxan on gastric secretion from pylorus-ligated rats may be interpreted in terms of increased excitatory vagal tone following the blockade of inhibitory alpha 2-adrenoceptors.
Blandizzi
C
C
Institute of Medical Pharmacology, University of Pisa, Italy.
Bernardini
M C
MC
Natale
G
G
del Tacca
M
M
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D004146:Dioxanes / Q000494:pharmacology; D005744:Gastric Acid / Q000378:metabolism*; D019329:Idazoxan; D007093:Imidazoles / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D010477:Perfusion; D011708:Pylorus / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000502:physiology*; D014628:Vagotomy; D015016:Yohimbine / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D004146:Dioxanes; D007093:Imidazoles; D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine; C041255:detomidine; D019329:Idazoxan