Inhibitory effect of beta-adrenergic-blocking agent propranolol on histamine-stimulated gastric acid secretion in man

Effects of intravenous famotidine on gastric acid secretion in patients undergoing cardiac surgery

OBJECTIVE

To determine the effects of cardiopulmonary bypass and famotidine on gastric acid secretion in adults undergoing cardiac surgery.

DESIGN

Prospective, randomized, double-blind, placebo-controlled study.

SETTING

University teaching hospital.

PARTICIPANTS

Eighteen patients undergoing elective cardiac surgery with cardiopulmonary bypass.

MAIN OUTCOME MEASURES

Famotidine 20 mg or NaCl 0.9% placebo was administered intravenously following induction of anesthesia and placement of a nasogastric pH probe. A second dose was given 12 hours after surgery in the intensive care unit. Gastric pH was measured continuously and gastric volume was measured every 4 hours for up to 24 hours after cardiopulmonary bypass.

RESULTS

Following famotidine administration, pH increased by 43% within 45 minutes and remained above 5.5 throughout the study period (p < 0.05 vs placebo and baseline). The gastric pH did not increase, but remained above 4.0 in most patients in the placebo group for up to 12 hours after cardiopulmonary bypass. Gastric volumes were on average 24% lower in the famotidine group (p > 0.05).

CONCLUSIONS

Gastric acid secretion is decreased during and for 12 hours after cardiopulmonary bypass. Perioperative administration of famotidine suppresses gastric secretion in cardiac surgery patients.

Investigation of drug absorption from the gastrointestinal tract of man. V. Effect of the beta-adrenoceptor antagonist, metoprolol, on postprandial gastric function

The role of the adrenergic system in normal gastric function was assessed in five healthy volunteers by measuring gastric secretion and emptying after a mixed meal containing a non-absorbable marker, [14C]-PEG 4000, with and without 100 mg of metoprolol, a beta 1-adrenoceptor antagonist. Intraduodenal perfusion of PEG 4000, and gastric and jejunal sampling was achieved by means of a gastrointestinal intubation technique. Gastric function was assessed from the degree of dilution of the duodenal marker. Analysis of acid content by titration allowed the gastric acid secretory rate to be determined. Gastric emptying of a meal over 4 h was similar with and without metoprolol, the time to 50% emptying being 100 min. In the presence of metoprolol, gastric acid content was significantly increased during the late postprandial period producing a corresponding increase in acid load delivered to the duodenum. beta 1-adrenoceptor blockade appears to prolong the gastric secretory response to food without altering gastric emptying.

Influence of beta blockade on gastric acid secretion and changes in gastric mucosal blood flow before and after parietal cell vagotomy in dogs and man

The aim of the present study was, in paired experiments in dogs, to examine the effect of beta-receptor blockade on gastric acid secretion and mucosal blood flow before and after parietal cell vagotomy (PCV). The secretory response to pentagastrin was reduced after vagotomy. beta-Adrenergic blockade had no effect on pentagastrin-stimulated gastric acid secretion before PCV, but after PCV beta blockade caused a modest increase in acid secretion, mediated mainly by the beta 2 receptors. A similar trend was seen in man. A marked increase in mucosal blood flow occurred 30 min after propranolol and was followed by a late decrease. One may conclude that a modest beta-adrenergic tone, which reduces secretion, becomes manifest after vagal denervation and that an increase in the ratio between mucosal blood flow and acid secretion was induced by the PCV. This increase cannot be explained as a beta-receptor-mediated effect.

Effects of metiamide and propranolol on gastric secretion in anesthetized dogs

The effects of metiamide, a histamine H2-receptor antagonist, and propranolol, a beta-adrenergic blocking agent, on gastric secretion were studied in anesthetized dogs. Metiamide, 1.45 mg/kg i.v., markedly inhibited the gastric secretion induced by a continuous i.v. infusion of tetragastrin (8 microng/kg-hr), histamine dihydrochloride (160 microng/kg-hr), or methacholine bromide (100 microng/kg-hr). Propranolol 0.5 or 1.0 mg/kg i.v. produced a significant potentiation of tetragastrin-induced gastric secretion but no influence of the secretion induced by methacholine. Propranolol at 5 or 10 mg/kg i.v. produced a slight reduction of the tetragastrin-induced secretion and a significant reduction of methacholine-induced secretion. Histamine-induced gastric secretion was not affected by propranolol at either 1 and 10 mg/kg i.v. These findings lend support to the hypothesis that interactions among histamine, gastrin and acetylcholine receptors do occur though the degree would not be the same in all directions.

Effects of propranolol on gastric secretion in albino rats

1 Effects of graded doses of propranolol have been studied on gastric secretion and gastric ulcers in pylorus-ligated rats.2 A dose-dependent action of propranolol was observed; small doses increased total volume, acid output and pepsin secretion along with an increase in the incidence of ulcers but high doses were inhibitory.

Can the actions of adrenoceptor agonists and antagonists on pentagastrin-induced gastric secretion be due to their effects of histamine formation?

1 The effects of some adrenoceptor agonists and antagonists which have been reported to affect histamine formation in leucocytes (Assem & Feigenbaum, 1972) have been investigated on gastric secretion in conscious dogs with Heidenhain pouches.2 Submaximal secretion in response to pentagastrin was enhanced by propranolol (0.1-1.0 mg/kg i.v.) and phenylephrine (1.0 mug kg(-1) min(-1) i.v. for 20 min), which increase histamine formation, and was decreased by phentolamine (2 mg/kg i.v.) and isoprenaline (0.05-0.2 mug kg(-1) min(-1) i.v. for 30 min), which decrease histamine formation. Practolol (2 mg/kg i.v.), which has no effect on histamine formation, had no effect on secretion.3 Acid secretion in response to histamine was either unaffected or affected in the opposite direction by these drugs.4 The effects of the drugs on pentagastrin-induced secretion were not secondary to changes in mucosal blood flow (radioactive aniline clearance).5 The results are consistent with the hypothesis that acid secretion in response to pentagastrin involves the formation of endogenous histamine.

Effect of propranolol on gastric acid secretion in rats

The effect of propranolol, a beta-adrenoceptor blocking agent, has been investigated on gastric acid secretion in pylorus and cardiac-ligated rats. Compared to the control group, propranolol significantly diminished the gastric acid secretion, and inhibited the formation of gastric ulceration.