The effect of phenoxybenzamine on the gastrin response to glycine stimulation

The nature of adrenergic mechanism involved in gastrin release in response to local stimuli and feeding is still unclear. In the present study, the effect of phenoxybenzamine, a potent alpha-blocking agent, on the gastrin release in response to glycine perfusion (pH 7.0) of an isolated canine antral pouch was examined. The experiment was repeated with truncal vagotomy performed before glycine perfusion. It was found that gastrin concentrations measured via right gastroepiploic vein were significantly increased during phenoxybenzamine infusion with and without truncal vagotomy. This finding indicates the presence of an alpha-adrenergic mechanism which inhibits gastrin release when the antrum is locally stimulated. After the drug was discontinued, though there was an enhancement in gastrin response in both saline and glycine perfused groups, the peak gastrin levels were reached earlier in the vagotomized dogs. This finding might indicate the influence of vagus nerve during the experiment.