Activation of pertussis toxin-sensitive G-proteins in membranes of SH-SY5Y human neuroblastoma cells and bovine transducin by ethanol.

Effects of ethanol on signal transduction in neuronal membranes are supposed to occur by the interaction with heterotrimeric guanine nucleotide-binding proteins (G-proteins). Several substances affect signal transduction by activation of G-proteins directly independent of receptors. We show that similar to those substances, ethanol stimulates high-affinity guanosine triphosphate (GTP)-hydrolysis in SH-SY5Y membranes at concentrations of 50 mM and higher in a pertussis toxin-sensitive manner. Compared with ethanol at a concentration of 170 mM, other alcohols were without or with respect to methanol with a slight effect on high-affinity GTP-hydrolysis in SH-SY5Y membranes. Ethanol also stimulates the GTPase of the purified G-protein transducin. The findings suggest that ethanol affects signal transduction in neuronal membranes by direct activation of pertussis toxin-sensitive G-proteins.