Lack of effects of glycine(B) receptor ligands on the psychostimulant-induced discriminative stimuli in rats

To examine the role of glycine(B) receptors in the stimulus effects induced by psychostimulants, separate groups of rats were trained to discriminate amphetamine (AMPH; 1 mg/kg) from saline(SAL), or cocaine (COC; 10 mg/kg) fr om SAL, using a two-lever operant procedure. Substitution studies showed th at neither 1-aminocyclopropanecarboxylic acid (ACPC; 200 mg/kg) nor 7-chlor o-4-hydroxy-3-(3-phenoxy)phenyl-(H)quinolone (L-701,324; 3 mg/kg), being a partial agonist or an antagonist at glycineB receptors, respectively, gener alized for the training drugs. Combination tests of glycine(B) ligands demo nstrated that injection of a fixed dose of ACPC (200 mg/kg) or L-701,324 (3 mg/kg) together with different doses of AMPH or COC practically did not mo dify dose-response curves of the psychostimulants, nor did it affect their ED50 values. Our results indicate that glycine(B) receptors do not play a r ole in the discriminative effects of AMPH and COC.