Characteristics of bombesin-induced inhibition of intake of ethanol.

The temporal and neural dependencies of the inhibitory effect of the administration of bombesin tetradecapeptide (BBS) on the intake of ethanol were assessed in the water-deprived rat. Variation of the intraperitoneal (i.p.) injection of neuropeptide--5% ethanol access interval (0-20 min), revealed that suppression induced by bombesin (0.5-4.0 micrograms/kg) was significantly greater and more potent at shorter intervals. The intake of ethanol was less in rats with subdiaphragmatic vagotomies, but bombesin equivalently suppressed the intake. Intracerebroventricular injection of bombesin more potently and completely inhibited the intake of ethanol but bombesin injected intraventricularly, unlike that given intraperitoneally, elicited excessive grooming and scratching behavior. The suppressant effect of bombesin, given intraperitoneally, requires close temporal contiguity of administration and caloric solution access, which is consistent with a satiety action of a neuropeptide. This satiation effect to ethanol of peripherally administered bombesin appears to reflect a non-vagal, extra-ventricular neural action.