Mazindol effects on schedule-controlled responding of the pigeon

The effects of mazindol, a non-phenethylamine anorexic, were determined in pigeons key pecking under a multiple fixed-ratio 30 response, fixed-interval 5 min schedule of food presentation. The low average rates of responding under the fixed-interval schedule were greatly increased (from 0.7 response/sec to 2 responses/sec) at doses from 0.1 to 10 mg/kg. The higher rates of responding under the fixed-ratio schedule were only decreased by increasing doses of mazindol. Throughout the fixed interval, mazindol tended to produce a constant rate of responding completely disrupting the normal, positively accelerated pattern of responding. These rate-increasing effects of mazindol were much greater than those of phenethylamines tested under similar conditions. The large increases in rates of responding under the fixed-interval component were discussed in terms of the known biochemical effects of mazindol.