[Membrane potential clamping in the horizontal cells of the fish retina]

The membrane potential of horizontal cells was clamped using uniform polarization of a layer of these cells by means of current passed via extracellular electrodes. It is shown that the voltage-current relationship of the nonsynaptic membrane of horizontal cells has in some cases sections with a negative slope. With fast shifts in the clamped potential level the changes in the membrane resistance are completed less than for 20 ms. Comparison of responses to light stimulation recorded with potential clamp and without it showed that participation of the nonsynaptic membrane in generation of responses to light stimulation can change significantly the form of the latter.