Characterization of alpha 2-adrenoceptor subtypes involved in the modulation of gastric acid secretion.
The effects of several alpha 2-adrenoceptor agonists and antagonists were examined on gastric acid secretion from reserpinized rats undergoing electrical stimulation of the left vagus nerve. Both detomidine and oxymetazoline inhibited vagal acid hypersecretion, their effects being fully prevented by idazoxan, 7,8-(methylenedioxy)-14-alpha-hydroxyalloberbane (CH 38083), or 2-(2-methoxy-1,4-benzodioxan-2-yl)-2-imidazoline (RX 821002), and partly antagonized by yohimbine or rauwolscine. 2-(2,4-(O-methoxy-phenyl)-piperazin-1-yl)-ethyl-4,4-dimethyl-1,3-( 2H,4H)-isoquinolindione (ARC 239) did not affect the antisecretory action of the two agonists, while prazosin at the highest dose was partly effective only against detomidine. Atropine markedly reduced vagally evoked acid output. It is suggested that acid secretion induced by vagal cholinergic stimulation is modulated by alpha 2A-like adrenoceptor subtypes.
Blandizzi
C
C
Institute of Medical Pharmacology, School of Medicine and Dentistry, University of Pisa, Italy.
Natale
G
G
Colucci
R
R
Carignani
D
D
Lazzeri
G
G
Del Tacca
M
M
D058647:Adrenergic alpha-2 Receptor Agonists; D058669:Adrenergic alpha-2 Receptor Antagonists; D000818:Animals; D004558:Electric Stimulation; D005744:Gastric Acid / Q000378:metabolism*; D008297:Male; D009411:Nerve Endings / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D018341:Receptors, Adrenergic, alpha-2 / Q000502:physiology*; D017661:Receptors, Presynaptic / Q000187:drug effects; D012110:Reserpine / Q000494:pharmacology; D014630:Vagus Nerve / Q000187:drug effects / Q000502:physiology
D058647:Adrenergic alpha-2 Receptor Agonists; D058669:Adrenergic alpha-2 Receptor Antagonists; D018341:Receptors, Adrenergic, alpha-2; D017661:Receptors, Presynaptic; D012110:Reserpine