Participation of emotional structures of the brain in the regulation of gastric secretory function.

The influence of the self-stimulation (SS) positive-reinforcement zones of the brain on the secretion of gastric juice was investigated using eight adult dogs with gastric fistulas. An intracerebral-S3 instrumental response was developed after implanting concentric (bipolar) electrodes into various zones of the reward system (hypothalamus, mammillary bodies, ventral thalamic nucleus, commissura grisea media, internal capsule, nucleus of the stria terminalis, and the crus cerebri). A normal acidity of the stomach contents was found in five dogs after surgery during the interdigestive period and a sharply elevated acidity in three dogs. A large quantity of thick foamy mucus and a turbid juice was secreted 3-5 min after the onset of SS. Self-stimulation did not alter the pH of the stomach contents in dogs with an initially normal pH, while it normalized this parameter in dogs with an initially elevated acidity. Bilateral supradiaphragmatic vagotomy in the animals of the latter group shifted the pH in the alkaline direction; however, the pH was completely normalized only as a result of intracerebral SS. Thus, positive emotional excitation associated with the stimulation of various reward zones normalized the acidity of the stomach contents; moreover, this response was not associated with the efferent systems of the vagus nerves.