Figure 1.
EtOH increases GABAergic transmission to granule cells. A, Simplified representation of the basic cerebellar cortical circuit. For clarity, we show only the components of the circuit that are relevant to this study. Mossy fibers, which come from the spinal cord and brain stem, provide excitatory input to granule and Golgi cells. Granule cells receive inhibitory input from Golgi cells. Granule cells provide excitatory input to Purkinje cells and Golgi cells via the parallel fibers. B, Sample traces of GABAergic currents recorded from a cerebellar granule neuron before (control; Ctrl) and during application of 50 mm EtOH and after washout (W/O). Note that EtOH induced a reversible increase in sIPSCs frequency, an inward current shift, and an increase in background noise. GABAergic currents were blocked by bicuculline (20 μm). Calibration: 40 pA, 10 sec. C, Expanded time scale sIPSC traces illustrating that these events can be clearly distinguished from background noise. Calibration: 50 pA, 200 msec. D, Frequency histogram corresponding to the recording shown in B, illustrating the effect of EtOH on sIPSC frequency as a function of time. E, Cumulative probability frequency histograms corresponding to the recording shown in B. F, Same as in E but for amplitude. G, Average sIPSC traces obtained from the recording shown in B. Calibration: 10 pA, 5 msec. Note that EtOH does not affect the amplitude or decay of these currents.