Effects of piribedil on schedule-controlled responding of the pigeon

The effects of piribedil were studied in pigeons responding under a multiple fixed-ratio 30-response, fixed-interval 5-minute schedule of food presentation. Piribedil (0.03-10 mg/kg) increased responding under the fixed-interval component to a much greater extent than d-amphetamine (0.3-3 mg/kg) did. The rate-increasing effects of piribedil on fixed-interval responding were attenuated by haloperidol (0.003 and 0.03 mg/kg), alpha-methyl-p-tyrosine (50, 100 and 200 mg/kg), and tetrabenazine (10 and 30 mg/kg). These drug interactions suggest that piribedil acts as an indirect-acting, dopaminergic agonist to produce its rate-increasing effects on schedule-controlled responding in the pigeon.