THE EFFECTS OF CCKA AND CCKB ANTAGONISTS ON ACTIVITY IN THE BLACK-WHITE EXPLORATION MODEL OF ANXIETY IN MICE

In view of evidence suggesting that cholecystokinin (CCK) may have a role in the mediation of human panic disorders, it was predicted that CCK receptor antagonists may have anxiolytic-like activity in an animal model of anxiety, the black/white exploration test. Data revealed that, in mice, the CCK(A) receptor antagonist, devazepide (formerly L-364,718, MK-329), produced a clear anxiolytic-like profile with an inverted U-shaped dose-response curve centered around 5 mug/kg. Similarly, L-365,031, a specific, but less potent, CCK(A) antagonist, also produced a profile consistent with weak anxiolysis but only at 5 mug/kg. By direct contrast, the potent and specific CCK(B) antagonist L-365,260 had no robust anxiolytic-like effects in this test. Therefore, these data suggest that devazepide has the greatest effects in this model, that L-365,031 is only marginally active, and that L-365,260 is without influence. These results suggest that CCK(A) receptor mechanisms are involved in the mediation of anxiolytic-like effects in the black/white model of exploration in mice.