Cholecystokinin and Bombesin Inhibit Ethanol and Food Intake in Rats Selectively Bred for Ethanol Sensitivity

Cholecystokinin octapeptide (CCK‐8) and bombesin tetradecapeptide (BBS‐14) are brain‐gut neuropeptides shown to inhibit intake and choice of alcohol solutions and foods in a variety of species. Recently, Draski and colleagues selectively bred strains descended from N/Nih outbred Norway rats that differ in sleep time after injection of ethanol. The intake of 5% w/v ethanol, food, and water was measured in these rats with high, low, and control alcohol sensitivity (HAS, US, and CAS), after intraperitoneal injection of randomized sequences of doses of CCK‐8 or BBS‐14 (0–8 μg/kg). During baseline adaptation to water deprivation‐induced consumption of alcohol, LAS rats consumed reliably more ethanol than HAS or CAS rats. Injection of CCK‐8 or BBS‐14 significantly and equivalently suppressed intake of ethanol and food at 30 min after presentation in each group of rats. Water intake and food intake at 30–60 min following alcohol access was not affected by prior injection of either neuropeptide. Large differences in alcohol neurosensitivity (HAS > CAS > LAS) were observed in these rats' resting behavior for 1 hr after intraperitoneal injection of 1 g/kg of ethanol. These selectively bred alcohol neurosensitivity differences cannot be explained by corresponding differences in sensitivity to the inhibitory behavioral effects of CCK‐8 or BBS‐14. However, differences in alcohol intake and resting behavior do correspond to artificially selected sensitivities to ethanol's hypnotic effect.