relationship Po-Im-p /(N), where Im-p is the peak amplitude of the mean IPSC.The weighted mean single-channel conductance (gs) could be derived from the relationship gs=i/(Erev-Vn), where Ere is the reversal potential of glycine receptor mediated chloride currents, and Vi the holding potential. In this study, the equilibrium potential of chloride ions was about-35 mV Statistical analysis was performed using unpaired Student's t test and data were represented as mcans SD B-6lf7 7-4.( RCs " Filtering properties of BCs under voltage-clamp recordings. revaluate the( effect of filtering on the kinetics of IPSCs, we digitally- modeled bullfrog-retinal BCs with NEURON software (Hines and Carnevale. 1997) as following. Bullfrog BC has a soma of about 7 um in diameter, an axon of 50 um long and l um in diameter branching into two processes(30 um in length and 1 um in diameter), and a primary rite of 10-um long and 2 um in diameter branching into two thinner processes um long and l um in diameter/(measured from BC images) Taking a typical input resistance for BCs of 10 G@ when potassium channels were blocked during our experiments. we-can calculate a membrane conductance per unit area of 0. 143 S, o drind e Assume a cytoplasm resistivity of 200 O-cm and a specific membrane capacitance of lyF-cm this would lead to a space constant a)of about 935 ym for d. c and about 197 um for 100 Hz a c. t value much longer than the typical length of uL BC dendrites and axon. For typical glycinergic IPSCs studied in present work with a 10-90% rise time(t)of 1.5-3.5 ms, a decay time constant(tp)of 10-40 ms and a peak amplitude (p)of 5-30 pA, T, and to will be slowed down less than 10%and 5%, respectively, and Ip will be decreased about 7% even when IPSCs were elicited from the end of bc dendrites or axon