Influence of luteinizing hormone releasing hormone (LHRH) on the behavioral effects of amphetamine in rats.

ABSTRACT

The influence of luteinizing hormone releasing hormone (LHRH) on the behavioral effects induced by several doses of D-amphetamine (0.25, 0.5, 1.0 and 2.0 mg/kg IP) was studied. A dose response relation was previously established for the effects of LHRH (50, 100 and 200 micrograms/kg SC) on acquisition and retention of conditioned avoidance responses (CARs). The neuropeptide impaired acquisition and improved retention of CARs, without modifying spontaneous motor activity. Pretreatment with 100 micrograms/kg of LHRH antagonizes the enhancement in acquisition of CARs due to D-amphetamine 0.5, 1.0 and 2.0 mg/kg, the impairment in retention induced by amphetamine 1.0 and 2.0 mg/kg, and the hypermotility and the increased rearing behavior induced by amphetamine 1.0 and 2.0 mg/kg. These results suggest that brain catecholamines, particularly dopamine, could play a role in the behavioral effects of LHRH. Interactions between LHRH and central dopaminergic mechanisms are discussed.