Effects of Ginkgo biloba on arterial smooth muscle responses to vasoactive stimuli.

1. An extract of Ginkgo biloba (Gb), at a concentration (100 microgram/ml) that did not provoke isometrically-recorded contractions of rabbit aorta, was tested on the contractile effects of norepinephrine (NE), serotonin (5-HT) and dopamine (DA). 2. Gb potentiated the contractile effect of NE (reduced the EC50 from 75 to 36 nM), but had no obvious action on the contractile effects of 5-HT or DA. 3. These results indicate that low concentrations of Gb might influence catecholaminergic systems by an indirect mechanism.