Fig. 5.
Differential effects of ethanol and guanosine 5′-O-(3-thiotriphosphate) (GTPγS) on Cl− currents activated by synaptic and exogenous glycine. A: effects of ethanol on the decay time constant and amplitude of mIPSCs, where each neuron was its own control (inverted triangles and filled circles show % change on each individual neuron; n = 26). Means ± SE are indicated by the segmented lines. Inset: protocol for mIPSC recordings. Ethanol solution was applied by switching from a pipette containing normal external solution to one with ethanol (circles). Here, glycine (star) is released from presynaptic vesicles and interacts with postsynaptic GlyRs. B: potentiation of glycine-evoked current (EC10–20 of glycine) in the presence of ethanol (100 mM) compared with the control (*P < 0.0001, paired Student's t-test, n = 12). Top inset: protocol for glycine-elicited current recording. Glycine and ethanol solution were applied by switching from a pipette containing normal external solution to one with glycine (stars) plus ethanol (circles), resulting in the activation of both synaptic and nonsynaptic GlyRs. Bottom inset: traces of glycine-activated currents in the presence of 100 mM ethanol (+EtOH) compared with the control (Gly). C: % mIPSC change obtained after 15 min of intracellular dialysis of GTPγS. Each cell is its own control (n = 19). Means ± SE are indicated by the segmented lines. D: % potentiation of glycine-elicited currents in the presence of GTPγS (500 μM) at minute 15 compared with the control (EC10–20 of glycine) at minute 1 (*P = 0.033, paired Student's t-test, n = 9 neurons). Inset: representative traces of glycine-activated current at minutes 1 and 15 of intracellular dialysis of GTPγS.