| 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.
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