Antagonism by baclophen of the d-amphetamine-induced disruption of a successive discrimination in the rat.

Male rats were trained to performa conditioned avoidance response combined with a successive discrimination in a shuttle-box. The administration of -amphetamine, 4 mg/kg i.p., caused a disruption of the discriminative but not thee avoidance behavior. Baclophen (beta-[-4-clorophenyl]-psi-aminobutyric acid), a GBA-derivative, given in a dose (4 mg/kg i.p.) that had no effect per se on the behavior in this test situation antagonized the -amphetamine-induced hypermotility. The present findins that baclophen antagonized a biochemically induced abnormal behaviour point to an "antipsychotic" action of baclophen in a successive discrimination avoidance test.