Abstract: Effect of sophocarpine and other alkaloid-s from Sophora alopecuroides L. on monoamine metabolism and D-2, 5HT₁ and 5HT₂ were studied by HPLC-electrochemical detection and receptor binding assay. Sophocarpine (SPC), lehmannine (LM), sophoramine (SPR), sophoridine (SPD) and matrine were found to significantly increase the dopamine metabolites dihydroxyphenylacetic acid (DOPAC) and or homovanillic acid (HVA) to various extent in rat striatum and limbic area. No effect of oxymatrine was observed in the experiments. LM also reduced the contents of DA in the striatum and NA in the limbic area. The elevation of HVA by SPC (40 mg/kg) lasted longer than that of DOPAC. The increase in HVA and DOPAC by SPC in the dose range of 10～80 mg/kg was dosedependent. At a higher dose (80 mg/kg) of SPC the DA content in the striatum was lowered. The data from in vitro radioreceptor binding assay showed that all tested compounds (LM not tested) showed no affinity for D-2. 5HT₁ and 5HT₂ receptors (IC₅₀>10^-4mol). It is likely that the central depressant activities of SPC, LM, SPR and matrine may be related to the changes of monoamine metabolism. All tested alkaloids showed no effect on the NA content in rat heart.