[Effects of bromazepam on responses of mucosal blood flow of the gastrointestinal tract and the gastric motility to stimulation of the amygdala and hypothalamus in conscious cats].

Electrical stimulation (ES) of the nucleus amygdaloideus centralis ( NAmC ) and basolateralis ( NAmBL ), like norepinephrine, decreased mucosal blood flow of the gastric antrum and duodenum and decreased antral motility amplitude in gallamine-immobilized cats. ES of the nucleus lateralis hypothalami (NHL) less extensively produced a similar action. The NAmC stimulation elevated BP and renal sympathetic discharges, whereas the NAmBL stimulation lowered BP. These findings indicate that the gastric and pressor responses to the NAmC stimulation may be attributed to an increase in cerebral sympathetic outflow. Bromazepam dose-dependently (0.1 approximately 1.0 mg/kg, i.v.) prevented these gastric, pressor and renal sympathetic responses to the NAmC stimulation, but it did not alter the depressor response to the NAmBL stimulation or the norepinephrine-induced reactions. Bromazepam less extensively attenuated the gastric and pressor responses to the NHL stimulation. Moreover, bromazepam inhibited stress-induced gastric ulcer formation in rats more markedly than cimetidine, sulpiride and metoclopramide. Bromazepam markedly decreased stress-induced selective increase in the glucose utilization rate in the NAmC among various amygdala nuclei. These results indicate that effects of bromazepam on the gastric and pressor responses to the NAmC stimulation may be due to the inhibition of central sympathetic outflow, and the NAmC are more sensitive to bromazepam than the NHL and other amygdala nuclei.