The effect of neurotransmitters on cataleptic behavior induced by PG D2 in rats

The effects of several neurotransmitters on prostaglandin (PG) D2-induced cataleptic behavior in rats were investigated by the high bar test. Intracerebroventricular administration of PG D2 elicited cataleptic behavior in a dose-dependent manner without producing a marked change in spontaneous motor activity. The incidences of cataleptic behavior were 20% and 100% at doses of 2 nmol and 50 nmol of PG D2, respectively. Intraperitoneal pretreatment with L-DOPA (100 mg/kg), apomorphine (1 mg/kg), amantadine (0.2 mg/kg), atropine (0.5 mg/kg) or p-chlorophenylalanine (300 mg/kg) significantly decreased the cataleptic behavior induced by 50 nmol of PG D2. Conversely, simultaneous treatment with 5-hydroxy-L-tryptophan (30 mg/kg), 5-methoxy-N,N-dimethyltryptamine (5 mg/kg), imipramine (20 mg/kg) or clomipramine (10 mg/kg) markedly increased the cataleptic behavior induced by 2 nmol of PG D2. Propranolol (10 mg/kg) and phenoxybenzamine (10 mg/kg) did not affect the induction of cataleptic behavior by either 2 nmol or 50 nmol of PG D2. These results suggest that PG D2 might be involved in inducing cataleptic behavior by modulating serotonergic, cholinergic and dopaminergic systems.