Pirenzepine depresses plasma noradrenaline in duodenal ulcer patients

The effect of pirenzepine--a selective antimuscarinic compound--on plasma catecholamine, serum gastrin and somatostatin concentrations was studied in duodenal ulcer patients. Plasma concentration of noradrenaline decreased significantly after injection of pirenzepine (10 mg intravenously), whereas the circulating levels of adrenaline, dopamine, gastrin and somatostatin remained unchanged. The results may be explained by a decreased activity in postganglionic sympathetic ganglia. This is in line with the recent observation in vitro that pirenzepine effectively blocks muscarinic receptors in some sympathetic ganglia.