Catechins from green tea modulate neurotransmitter transporter activity in Xenopus oocytes

Abstract The GABAergic and glutamatergic systems play key roles in controlling activity of the central nervous system. Important membrane proteins in the mammalian central nervous system transporting extracellular GABA and glutamate are the GABA transporter GAT1 and the glutamate transporter EAAC1. We investigated the effect of catechins of green tea (Camellia sinensis) on the activity of GAT1 and EAAC1 by detecting the respective electrogenic transporter-mediated current under voltage clamp. Epigallocatechin-3-gallate inhibited GAT1-mediated current to 50% at about 100 μM. The EAAC1-mediated current could be stimulated up to 80% by (-)-epicatechin; 50% of maximum stimulation was achieved by about 5 μM. Inhibition of GAT1 and stimulation of EAAC1 will counteract hyperexcitability.