Facilitation of self-stimulation with high doses of amphetamine in the rat.

Rats were trained to self-stimulate by interrupting a photobeam and brain stimulation was maintained for as long as the beam of light was broken. d-Amphetamine sulphate was then administered and response rate and total duration of stimulation were recorded. Both response rate and total duration were elevated by 1.0, 2.0, and 5.0 mg/kg dosages. The 1.4 s/response duration observed with saline was elevated to 2.0 s/response with 2.0 and 5.0 mg/kg doses. It was concluded that amphetamine's effects on self-stimulation are at least partially determined by the response requirements of the task employed.