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.