EFFECT OF RESERPINE ON SERUM GASTRIN CONCENTRATION AND ON MUCOSAL AMINES AND AMINO ACID DECARBOXYLASE ACTIVITIES IN RAT STOMACH

¹ Departments of Pharmacology, Surgery and Histology, University of Lund, Sweden, Department of Clinical Chemistry, Bispebjerg Hospital, Copenhagen, Denmark, and Department of Anatomy, University of Gothenburg, Sweden

Reserpine is known to reduce gastric mucosal 5-hydroxytyptamine and histamine. The present study shows that this effect of reserpine in the stomach of the rat is independent of an intact extrinsic autonomic innervation and probably results from a direct action on the amine storage mechanisms. Reserpine failed to affect pyloric histidine decarboxylase but caused a short-lasting reduction in oxyntic histidine decarboxylase activity followed by a progressive rise in the enzyme activity back to "normal" or even "supra-normal" values, an observation which confirms earlier reports from other laboratories. This characteristic pattern was observed in both vagotomized and unoperated rats. The reduction of enzyme activity was interpreted as the result of enzyme leakage from the histamine-producing cells of the oxyntic mucosa or of specific inhibition of histidine decarboxylase synthesis. The increase in enzyme activity was prevented by antrectomy, suggesting that the activation was a result of reserpine-induced gastrin release. This assumption was supported by the finding of an increase in serum gastrin concentrations coinciding in time with the enzyme activation.