In this work, the influences of cholecystokinin receptor antagonists L-365,260, MK-329 and proglumide on antinociception induced by baclofen and GABA uptake inhibitor 4,5,6,7-tetrahydroisoxazolo [4,5-c]pyridin-3-ol (THPO) in the tail flick test has been studied. Baclofen and THPO induced antinociception in the tail flick test. Morphine, and the CCK receptor antagonists, MK-329, L-365,260 and proglumide also induced antinociception. The CCK receptor antagonists potentiated antinociceptive response induced by both baclofen and THPO. It may be concluded that cholecystokinin receptor mechanism(s) may interact with antinociception induced by GABA receptor mechanism(s).