Diazepam reverses bombesin-induced gastric spasms and food intake reduction in the rat.

Bombesin (2-16 micrograms/kg, i.p.) produced abnormally large gastric contractions in intact rats consisting of increases in gastric pressure and motility. The effect was antagonized by diazepam (5 mg/kg, i.p.). The same dosage of diazepam abolished bombesin-induced food intake reduction. Diazepam by itself did not increase food intake above control levels. The time course of this behavioral antagonism was followed. There was no significant difference in the intake time course of diazepam-alone and diazepam-bombesin treatments, while there was a significant difference between the saline control and the bombesin-alone treatments. Intake of the saline control, the diazepam-alone and the diazepam-bombesin treatment terminated at the same level, while the bombesin-alone remained significantly different. Additionally, swift aversion to 8 micrograms/kg bombesin was obtained when flavored nutrient was substituted for flavored water, suggesting that the aversion developed as a consequence of interaction with the ingested diet. Abnormalities that result from intake reduction is due to the bombesin-produced intragastric abnormalities, and not by satiety.