演題番号 : P1-a27
佐竹 伸一郎 / Shin'Ichiro Satake:1,2 井本 敬二 / Keiji Imoto:1,2
1:生理研・生体情報 / Department of Information Physiology, National Institute for Physiological Sciences (NIPS), Okazaki, Japan 2:総研大・生命科学 / School of Life Science, The Graduate University for Advances Studies (SOKENDAI), Okazaki, Japan
Repetitive activation of climbing fibers (CFs) not only excites the postsynaptic Purkinje cells (PCs) but also inhibits GABA release from basket cells (BCs) converging on the same PC through extrasynaptic diffusion of the transmitter and following activation of AMPA receptors expressed in BC terminals (Satake et al., 2000, 2006). We here report that the CF-induced heterosynaptic inhibition was suppressed by ethanol in a concentration-dependent manner (up to 100 mM). Ethanol neither affected aspects of the glutamate release at CF-PC synapses nor the presynaptic inhibitory action of AMPA receptors. The suppressive effect of ethanol disappeared in the presence of blockers for excitatory amino acid transporters (EAATs). The results suggest that ethanol augmented glutamate uptake capacity of the perisynaptic EAATs and thereby suppressed intersynaptic diffusion of the CF transmitter that mediates the presynaptic inhibition.