The effects of phencyclidine, ketamine, delta-amphetamine and pentobarbital on schedule-controlled behavior in the mouse.

The response of mice of breaking a light beam onto a photocell was programmed to produce food according to a multiple schedule with alternating 30-response fixed ratio, 300-second fixed interval (FR-30 FI-300 sec) components. Training was standardized for all mice, and stable patterns of responding that were similar to those described for other species and responses under this schedule developed quickly. The effects of pentobaribtal, delta-amphetamine, phencyclidine and ketamine were studied. At some dose, each of the four drugs produced an increase in rate of responding; the increase was proportionately greater at low rates of responding than at higher rates. At some dose range, delta-amphetamine, ketamine and phencyclidine produced dose-related increases in FI average rates were to 1.83, 1.25 and 1.32 times the control rate for delta-amphetamine (1 mg/kg), ketamine (100 mg/kg) and phencyclidine (3 mg/kg), respectively. Phencyclidine and ketamine thus showed some "amphetamine-like" effects in the mouse. Pentobarbital increased (1.25 times the control rate) both the FR and FI response rates at a dose of 3 mg/kg. Higher doses of pentobarbital progressively decreased both FR and FI response rates in a parallel fashion.