Antioxid Redox Signal. 2000 Fall; 2(3): 467-71.

Ginkgo biloba abolishes aggression in mice lacking MAO A.

Shih JC, Chen K, Ridd MJ, Seif I.

University of Southern California, Department of Molecular Pharmacology and Toxicology, School of Pharmacy, Los Angeles 90089, USA. jcshih@hsc.usc.edu

Mice deficient in monoamine oxidase A (MAO A) have increased brain levels of serotonin (5-HT) and norepinephrine and show enhanced aggression. We used MAO A knock-out (KO) mice as a model to study the effect of ginkgo biloba (EGb) on aggression. When EGb was administered to MAO A KO mice, their aggressive behavior in resident-intruder confrontations was reduced to levels seen in wild types. EGb did not affect the locomotive behavior of MAO A KO mice, which suggests that its effects on aggression were not due to sedation. EGb caused a significant 16.9% decrease in [3H]ketanserin binding to 5-HT2A receptors in the frontal cortex of MAO A KO mice but did not change the receptor affinity for [3H]ketanserin. This suggests that the antiaggressive effect of EGb may be mediated by 5-HT2A receptors and that EGb may be developed as a novel antiaggressive agent.