The effect of anticholinergic drugs on the electrolyte content of gastric juice

Abstract

SYNOPSIS Gastric secretion was stimulated by insulin hypoglycaemia and the effect of increasing doses of anticholinergic drugs on the volume, acid, and electrolyte content of gastric juice was studied. The sodium and potassium output was depressed to a far less extent than the acid output and the drop in volume of secretion and acid output after anticholinergic drugs is almost entirely due to decreased acid secretion. With increasing anticholinergic suppression of the volume of secretion, there is a marked fall in potassium output and a lesser fall in sodium output. The potassium concentration showed a slight fall and there was a rise in sodium concentration.The effect of various anticholinergic drugs on gastric acid secretion has been studied by many workers. The acid concentration and output so investigated represents the amount of parietal secretion remaining after dilution and partial neutralization by the alkaline component, chiefly mucus and sodium and potassium chloride and bicarbonate. Hence it is of some interest to know the effect of anticholinergic agents on the electrolyte content of gastric juice; as far as can be ascertained, this has not been previously studied. METHODSThe patients studied were psychiatric patients having insulin coma therapy. All were free of gastrointestinal disease. Their repeated treatment enabled many observations to be made on the same patient. A Cleland tube was passed when the patient became comatose, coma being considered to be present when patients no longer responded to painful stimuli and bilateral extensor plantar responses were present. Continuous suction was applied for about 15 minutes to remove the gastric residue and two 15-minute specimens were collected during the last 30 to 45 minutes spent in coma. Blood sugar estimations were done initially but were discontinued when it was found reproducible control results were obtained under the above conditions, whatever the actual blood sugar level found. Patients were included in this study only if the control secretory rates were high (>3 ml./min.) and the specimens were not bile-stained.The series of anticholinergic drugs included atropine, propantheline, oxyphencyclimine, and propionyl atropine methyl nitrate. These were administered orally two to two and a half hours before the onset of coma.From the design of the experiments, maximal hypoglycaemic stimulation was considered to be present because the patients were comatose from hypoglycaemia during the period gastric secretion was collected. That this is a constant base line from which to assess changes is shown by the fact, discussed later in this article, that in 10 control observations on three patients the standard deviation was only 3-7% of the mean secretion under these circumstances. A greater error than this could be expected, however, when the volume of secretion was small. It is appreciated that the time of maximum action of the drugs administered varied and would not necessarily coincide with the time of collection of gastric juice. It is seen in Table I...