Mechanism of the Vagotomy-induced Suppression of the Maximal Acid Response to Histamine in Antrectomized Duodenal Ulcer Patients

Abstract

After resection of the antrum and duodenal bulb in 6 duodenal ulcer patients the maximal acid response to histamine (MHR) was determined without and with conduction anaesthesia of the nervi vagi and after vagotomy. This vagotomy, like the conduction anaesthesia, was carried out by means of a device which did not require further laparotomy. The blocking of the vagus by conduction anaesthesia was found to be complete by means of an insulin test. MHR during conduction anaesthesia, immediately after and 6–8 weeks after vagotomy showed a similar and significant reduction of MHR.

In 10 duodenal ulcer patients with resected antrum and duodenal bulb, MHR was determined before and after vagotomy and thereafter during simultaneous administration of carbacholine and histamine. A carbacholine-induced increase of MHR after vagotomy could be noted. There were individual variations in the necessary amount of the carbacholine dose but the increase of MHR took place in the subthreshold area for carbacholine even up to pre-vagotomy value for MHR. Suprathreshold doses of carbacholine resulted in no further augmentation of MHR.

The result shows that the reduction of MHR after vagotomy is not caused by atrophy of the parietal cells and that the parietal cells, in the absence of the gastrin producing areas, within the subthreshold area for cholinergic activity are quantitatively dependent on this activity in their response to maximal histamine stimulation.

Index-words:

• Stomach
• gastric juice
• histamine
• peptic ulcer
• gastric acidity determination
• gastrectomy
• vagotomy