In vitro studies. A standardized extract of Ginkgo biloba (100μg/ml) did not
produce isometrically recordable contractions in isolated rabbit aorta but did
potentiate the contractile effect of norepinephrine (30). Higher concentrations
(EC50 1.0 mg/ml) produced a concentration-dependent contraction that could
be antagonized by the α-adrenoceptor-blocking agent phentolamine (30). Both
cocaine and desipramine, inhibitors of catecholamine re-uptake, potentiated
the contractile effect of norepinephrine but inhibited the contractile effects of a