Ethanol suppression of schedule-controlled responding: interactions with Ro 15-4513, Ro 15-1788 and CGS 8216.

Rats (N = 14) were trained to respond under a five seconds differential reinforcement of low rate (DRL 5'') schedule and under a fixed ratio 10 (FR10) schedule of reinforcement. Ro 15-1788 did not influence the number of responses in the DRL 5'' schedule, but increased responding in the FR10 schedule. Ethanol (ETOH, 1250 mg/kg) and CGS 8216 (5 mg/kg) suppressed responding in both schedules and these effects were not antagonized by Ro 15-1788. The response suppressing effects of ETOH in both schedules were not influenced by CGS 8216. These results indicate that the response suppressing effects of ETOH and CGS 8216 are not mediated by the BDZ receptor. Ro 15-4513 suppressed responding strongly in the FR10 schedule. The response suppressing effects of Ro 15-4513 were additive with the response suppressing effects of ETOH. In rats (N = 11) trained to respond under a variable interval 40 seconds-fixed ratio 10 (VI 40''-FR10) schedule Ro 15-4513 dose-dependently suppressed responding. These results indicate that Ro 15-4513 has sedative effects and is not able to antagonize all the behavioral actions of ETOH.