Influence of (-)-sulpiride and YM-09151-2 on stereotyped behavior in chicks and catalepsy in rats.

In this paper, the effects of three antipsychotic agents using the avian species laboratory model are described. d-Amphetamine (2-5 mg/kg, s.c.) dose-dependently antagonized catalepsy induced by haloperidol (0.25 mg/kg, i.p.), YM-09151-2 (0.02-0.04 mg/kg, i.p.) and (-)-sulpiride (20-40 mg/kg, i.p.) in rats. (-)-Sulpiride (10-40 mg/kg, i.p.) dose-dependently antagonized apomorphine (0.125 mg/kg, s.c.)-induced stereotyped behavior in young chicks. Similarly, YM-09151-2 (0.04 mg/kg, i.p.) antagonized apomorphine (0.125 mg/kg, s.c.)-induced stereotyped behavior in young chicks. (-)-Sulpiride (40 mg/kg, i.p.) significantly antagonized apomorphine (0.25 mg/kg, s.c.)-induced stereotyped behavior in 6 week old chicks. Parachlorophenylalanine (PCPA, 300 mg/kg, i.p.) significantly reduced the intensity of stereotyped behavior induced by apomorphine (0.125 mg/kg, s.c.) in young chicks. However, (-)-sulpiride (40 mg/kg, i.p.) did not significantly influence the effect of PCPA on apomorphine-induced stereotyped behavior. Similarly, catalepsy induced by (-)-sulpiride (40 mg/kg, i.p.), haloperidol (0.25 mg/kg, i.p.) and YM-09151-2 (0.04 mg/kg, i.p.) in male rats was profoundly suppressed by PCPA (300 mg/kg, i.p.). The present results indicate that apomorphine-induced stereotyped pecking in young (4-6 day old) chicks may serve as a suitable laboratory model for testing potential antipsychotic drugs. In addition, the data indicates that endogenous 5-hydroxytryptamine mechanisms may be involved in the genesis of drug-induced catalepsy in rats.