Effect of isoprenaline on pentagastrin-stimulated gastric acid secretion in dogs with gastric fistula.
The purpose of this study was to elucidate the effect of a beta 1-adrenoceptor agonist on gastric acid secretion in conscious dogs with gastric fistula. Isoprenaline, a beta 1- and beta 2-agonist was used alone and in conjunction with selective blockade of beta 2- and beta 1-receptors. Isoprenaline dose-dependently inhibited the secretory volume and the acidity. The antisecretory effect of isoprenaline was significantly blocked by the beta 1-adrenoceptor blocker practolol and by the beta 1 + beta 2-adrenoceptor blocker propranolol but not by H 35/25, a beta 2-adrenoceptor blocker. This indicates that isoprenaline acts on the acid secretion exclusively through beta 1-receptors. Dose-response experiments with five logarithmically increased doses of pentagastrin and one dose of isoprenaline showed unchanged calculated maximum response and an increase in half-maximum acid response. It is concluded that the inhibitory effect of isoprenaline on gastric acid secretion is of competitive or uncompetitive type.
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004809:Ephedrine / Q000031:analogs & derivatives / Q000494:pharmacology; D005260:Female; D005744:Gastric Acid / Q000378:metabolism*; D005747:Gastric Fistula; D007545:Isoproterenol / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008297:Male; D010418:Pentagastrin / Q000494:pharmacology; D011217:Practolol / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D013268:Stimulation, Chemical
D000319:Adrenergic beta-Antagonists; C004380:H 35-25; D011433:Propranolol; D010418:Pentagastrin; D004809:Ephedrine; D007545:Isoproterenol; D011217:Practolol