Kondrats'ka O. Glycine receptors in pyramidal hippocampal neurons of the rat and their modulation by ginkgolides

Using whole-cell patch-clamp technique, the main features of interactions of ginkgolides A, B, C and J with glycine receptors were elucidated. As examined on several other voltage- and ligand-operated channels, the action of ginkgolides is otherwise selective: the substance does not affect GABA-, AMPA- or NMDA-activated responses. The blocking action of all tested ginkgolides is use-dependent: they block open glycine-activated channels. On the basis of electrophysiological screening of terpenoid constituents of Ginkgo biloba extract we proposed the existance of a site specifically sensitive to ginkgolides inside a channel pore of the glycine receptor. According to experimental results as well as mathematical calculations it is concluded that ginkgolide B primarily affects heteromeric glycine receptors.