Reversal potential of GABA-induced currents in rod bipolar cells of the rat retina.
GABA-induced whole-cell currents were measured in rod bipolar cells dissociated from the adult rat retina. The patch-clamp electrode contained nystatin, which made the cell membrane electrically permeable without rupture, thus retarding the rate of diffusion of Cl- ions from the patch pipette to the cell interior. The reversal potential of the GABA-induced currents was around -70 mV at an extracellular Cl- concentration of 149 mM. We conclude that GABA generates hyperpolarizing responses in rod bipolar cells of the rat retina.