in mice: At 5 and 10 mg kg-', L-701,324 virtually abolished the propagation of SD and the drug was effective within 30 min after administration and for up to 2.5 h. These doses are around 5-10 fold the ED50 for inhibition of audiogenic seizures in the DBA/2 mouse, a model extremely sensitive to NMDA-receptor blockade. In contrast, 10 mg kg-' L-701,324 inhibited K+ elicitation by around 50% only. Pretreatment with L-701,324 dose-dependently antagonized amphetamine-induced hyperactivity in the mouse (ED50 = 1.12 +/- 0.45 mg/kg p.o.), an effect which was similar to that of the classical neuroleptic, haloperidol, and the atypical neuroleptic, clozapine. In addition, p.o. administration of L-701,324 (2.5 or 5 mg/kg) attenuated the hyperactivity response induced by amphetamine infusion into the rat nucleus accumbens. In contrast to haloperidol, however, stereotyped sniffing and licking/biting, induced by either the systemic administration of apomorphine or infusion of amphetamine into the striatum, was not altered in rats pretreated with L-701,324 (30 or 100 mg/kg p.o.).

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