Dual effects of electrical stimulation of ventromedial hypothalamic neurons on gastric acid secretion in rats.

Effects of electrical stimulation of the ventromedial hypothalamus (VMH) on gastric acid output and mucosal blood flow were examined in rats anesthetized with urethan. With stimulation of this area, a significant increase in acid output and mucosal blood flow occurred in 8 out of 16 animals. In these eight rats, the tip of the electrode had been placed mainly within the caudal portion of VMH. When the basal acid output was maintained at a relatively high level by pretreating the rats with 2-deoxy-D-glucose, electrical stimulation of the VMH significantly reduced the levels of these gastric parameters in 9 out of 12 animals. In the remaining three animals, the tip of the electrode had been placed in an area outside the VMH. These findings suggest that VMH is not a homogeneous neuron group, and both excitatory and inhibitory neurons probably play a role in regulating gastric functions.