Alpha adrenergic receptors and gastric function

Abstract

Taylor, J.A. and G. Nabi Mir: Alpha Adrenergic Receptors and Gastric Function. Drug Dev. Res. 2105-122,1982.Alpha-2 agonists by an effect on alpha-2 adrenoreceptors in the stomach (and probably in the brain also) suppress vagal nerve acetylcholine release thereby inhibiting gastric motility and secretion and inhibiting the development of gastric lesions in rats in the stress-, reserpine-, and cysteamine-induced ulcer models. Since the effects of the alpha-2 agonists are consistently inhibited by alpha-2 blocking agents, their effects appear to be selectively mediated via the alpha-2 receptor. It seems appropriate therefore that the role of the alpha-2 receptors be recognized in studies of gastric function and ulcer development.Address reprint requests to G .

The effect of phentolamine on basal and pethidine‐induced inhibition of gastric emptying in healthy volunteers.

“…Several studies have indicated that a2-adrenoceptor agonists and opiate agonists exerted similar effects in many systems other than the gastrointestinal tract (Taylor & Mir, 1982). The present study supports the hypothesis of a common mechanism of opioids and a2-adrenoceptor antagonists on gastric emptying.…”

“…In patients with duodenal ulcer intravenous administration of either 5 mg phentolamine, 2 mg propranolol or 10 mg metoclopramide all increased gastric emptying suggesting that the adrenergic system has an influence on gastric motility in such patients (Tkaczewski & Chojnacki, 1980). Since a,-adrenoceptors have been proposed to be less important in the regulation of gastric emptying than a2-adrenoceptors (Taylor & Mir, 1982) a more marked effect on basal gastric emptying might be obtained using a selective a2-adrenoceptor antagonist. It is well established that acute administration (i.v., i.m.)…”

“…Phentolamine, a non selective a-adrenoceptor antagonist considered to possess sympathomimetic, parasympathomimetic and histaminelike actions on smooth muscle, stimulates gastric secretion of both acid and pepsin (Cho & Ogle, 1978;Taylor & Mir, 1982). Although there is evidence that the motility of the gastrointestinal system is under the influence of adrenergic receptors (Taylor & Mir, 1982), studies concerning, in particular, the effect of phentolamine on gastric emptying in man and other species have yielded contradictory results (Cho & Ogle, 1978;Cooper & McRitchie, 1985; Thompson, 1988).…”

“…Although there is evidence that the motility of the gastrointestinal system is under the influence of adrenergic receptors (Taylor & Mir, 1982), studies concerning, in particular, the effect of phentolamine on gastric emptying in man and other species have yielded contradictory results (Cho & Ogle, 1978;Cooper & McRitchie, 1985; Thompson, 1988).…”

Inhibition of gastric acid secretion by intracerebroventricularly administered prostaglandin E2 in anaesthetized rats

“…These findings strongly suggest that central administration of PGE2 causes activation of the sympathetic nervous system. On the other hand, sympathomimetic compounds have an inhibitory effect on gastric acid secretion (Taylor & Nabi Mir, 1982). Accordingly, the possibility that the inhibition of gastric acid secretion by i.c.v.…”