THE BETA-CARBOLINE ABECARNIL, A NOVEL AGONIST AT CENTRAL BENZODIAZEPINE RECEPTORS, INFLUENCES SACCHARIN AND SALT TASTE PREFERENCES IN THE RAT

Abecarnil is a recently described beta-carboline which acts at central benzodiazepine receptors (BZR) and has anxioselective/anticonvulsant properties. While it may be classified provisionally as a partial agonist at BZR, there is also evidence that its pharmacological profile may be due to a selective action at BZR subtypes. The general aim of the present series of experiments was to investigate the effects of abecarnil on ingestional behaviour in the rat. The results indicated that abecarnil (0.3-10 mg/kg, i.p.) selectively increased the intake of preferred 0.05% sodium saccharin and 0.9% sodium chloride solutions in two-choice tests using water-deprived rats. These results confirm and extend previous work with the potent BZR agonist clonazepam. Moreover, abecarnil significantly increased the ingestion of sweetened mash and 3% sucrose solution in nondeprived animals. In general, these results indicate that abecarnil is effective in increasing ingestional responses, a characteristic it shares with classical agonists like diazepam. The results could be accounted for in terms of a partial agonist profile for abecarnil, but do not rule out the possibility of selective actions at BZR subtypes.