Caerulein and cholecystokinin octapeptide (CCK-8): sedative and anticonvulsive effects in mice unaffected by the benzodiazepine antagonist Ro 15-1788.

Cholecystokinin octapeptide (CCK-8), caerulein and diazepam inhibited exploratory rearing activity and harman-induced convulsions in mice. Pretreatment with the selective benzodiazepine receptor antagonist Ro 15-1788, reduced or abolished the sedative and anticonvulsive effects of diazepam, but left the same effects of both peptides unaffected. The peptide-induced ptosis was even increased by Ro 15-1788. The results suggest that the CCK-like peptides do not directly interact with the benzodiazepine receptor.