Inhibitory effect of isoprenaline on gastric acid secretion in the rat. The role of endogenous histamine.
In dogs beta-adrenoreceptor agonists inhibit gastric acid secretion stimulated by exogenous gastrin to a much greater extent than acid secretion stimulated by exogenous histamine. One possible explanation for this observation is that endogenous histamine is important in gastrin-mediated acid secretion and that isoprenaline and related beta-adrenoreceptor agonists block gastric mucosal histamine release. This possibility was tested in the present study in gastric lumen-perfused anaesthetized rats. Intravenous infusion of isoprenaline (12 microgram kg-1 h-1) inhibited maximal, pentagastrin-stimulated acid output by 50-70% (P less than 0.01), but had no significant inhibitory effect on the maximal acid secretory response to histamine. In contrast to its inhibitory effect on gastrin-stimulated acid output, isoproterenol had no effect on gastric histamine output during pentagastrin infusion. We conclude that isoprenaline selectively inhibits gastrin-stimulated acid secretion in the rat, as in the dog, and by a mechanism other than inhibiting gastric histamine release.
Heylings
J R
JR
Department of Internal Medicine, Veterans Administration Medical Center, Dallas, Texas.
Redfern
J S
JS
Feldman
M
M
D000818:Animals; D005260:Female; D005744:Gastric Acid / Q000378:metabolism*; D006632:Histamine / Q000502:physiology*; D006636:Histamine Release / Q000187:drug effects; D007545:Isoproterenol / Q000494:pharmacology*; D010418:Pentagastrin / Q000037:antagonists & inhibitors / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
D006632:Histamine; D010418:Pentagastrin; D007545:Isoproterenol