Differential effects of caerulein and bombesin on the ethanol intake in the rat

Male Wistar rats were allowed to drink either water or water mixed with ethyl alcohol (4%, 8% and 12%) as part of a water-deprived procedure. The decapeptide caerulein (1, 3 and 6 micrograms/kg i.p.), a cholecystokinin analog, decreased the intake of ethanol while the consumption of tap water remained unchanged in a choice paradigm. The addition of quinine (a bitter substance) in drinking bottles did not significantly modify the fluid consumption while the i.p. injection of caerulein produced a significant decrease in the consumption of the saccharin containing bottle. The i.p. administration of bombesin (10 and 20 micrograms/kg) failed to modify the intake of water or ethanol solution in water-deprived animals. Interpretations are given in terms of the action of the cholecystokinin analog on differences in the taste intensity induced by the beverage or in terms of a direct consequence of the caerulein-induced decreased gastric emptying effect leading to an accumulation of ethanol in the gut.