Methamphetamine, physostigmine, atropine and mecamylamine: effects on force lever performance.

Dose response functions for d-methamphetamine (MA), physostigmine, atropine, and mecamylamine on force lever performance (a measure of motor control) were determined in three rhesus monkeys. The rhesus monkeys were then treated with a repeated high dose regimen of MA, and the effects of the four drugs were redetermined. Following the completion of the behavioral studies, the monkeys were killed and brain monoamine concentrations were measured. It was found that each of the four drugs produced differential effects on force lever performance indices. Following the MA regimen, the MA-treated monkeys were less sensitive to the effects of MA on force lever performance but showed no change in sensitivity to any of the cholinergic agents. The monkeys were subsequently shown to have decreased brain dopamine and serotonin levels.