[Effects of l-stepholidine on the central nervous and cardiovascular systems].
l-Stepholidine (SPD) is one of the analogs of l-tetrahydroprotoberberines (THPB). It has been shown that SPD is a dopamine receptor antagonist. In this work, it was further demonstrated that SPD antagonized apomorphine-induced stereotypy in rats and apomorphine-induced vomiting in dogs. SPD produced a transient catalepsy in mice, and it caused a marked decrement of Ach level in the caudatum. All the results support the view point that SPD is an antagonist of dopamine receptors. 
On spontaneously activity in mice, SPD exhibited a diphasic action on amphetamine-effect. Following a brief antagonism, the potential effect of SPD on amphetamine was observed. 
In the anesthetized dogs given SPD 40 mg/kg, a decrement of arterial blood pressure by 63% within 10 min and a marked reduction of total peripheral resistance were observed stimutaneously, but without any adverse effect on heart.