Sulphated cholecystokinin octapeptide inhibits ethanol consumption in the rat

Twenty-three hr water deprived rats received access to 5% ethanol solution for 30 min daily. Intraperitoneal injection of sulphated cholecystokinin octapeptide (CCK-8, 2.0-16.0 micrograms/kg) significantly inhibited ethanol consumption, but injection of desulphated CCK-8 did not affect ethanol consumption. These results confirm a previous report that CCK-8 suppresses ethanol intake, and indicate that inhibition of ethanol consumption by CCK-8 depends on sulphation of its tyrosyl residue. This chemical specificity of action of CCK-8 is also characteristic of other known behavioral and physiological effects of peripherally-administered cholecystokinin-like peptides.