Vasoactive intestinal peptide: behavioral effects in the rat and hamster

The behavioral effects of intracerebroventricular (ICV) injection of the brain-gut peptide vasoactive intestinal peptide (VIP) were quantified with a behavioral sampling technique in home-caged, nondeprived, male and female albino rats and golden hamsters. ICV VIP sex-dependently decreased observed resting behavior during 1 hr after injections in both rats and hamsters at 0.1-10.0 micrograms. Grooming behavior was increased in hamsters, and rearing and standing behaviors were increased in rats, sex-dependently at VIP doses that decreased resting. Drinking behavior was suppressed in rats by VIP at 10.0 micrograms. Intraperitoneal (IP) VIP (100.0 micrograms/kg) increased 5% ethanol intake and decreased eating behavior in fluid-deprived male rats. The increase in ethanol intake produced by IP VIP was prevented by IP cholecystokinin octapeptide (CCK, 4.0 micrograms/kg). VIP potently controls resting and ingestive behaviors, suggesting a role for this neuropeptide, along with CCK, in the feedback regulation of rodent behavior.