AMPHETAMINE-LIKE STIMULUS PROPERTIES PRODUCED BY ELECTRICAL-STIMULATION OF REWARD SITES IN THE VENTRAL TEGMENTAL AREA

The present study examined whether the stimulus properties of d-amphetamine could be mimicked by electrical stimulation of the ventral tegmental area (VTA). Rats trained to discriminate 1.0 mg/kg d-amphetamine from saline were given generalization tests with a range of d-amphetamine doses administered either alone or in combination with VTA stimulation. The results suggested that the VTA stimulation could enhance the cueing effects of d-amphetamine, as levels of responding on the d-amphetamine-appropriate lever during stimulation trials were increased relative to tests without stimulation. Individual differences were observed in the amount of drug-lever responding elicited by the VTA stimulation during drug-free substitution tests, and the different levels of drug-lever responding correlated positively with the response rates obtained from these rats during subsequent intracranial self-stimulation tests. These findings suggest that VTA stimulation can have d-amphetamine-like stimulus properties and such stimulus properties may be related to the rewarding effects of the brain stimulation. © 1990.