H. Satoh et al., Intracellular chloride concentration is higher in rod bipolar cells than in cone bipolar cells of the mouse retina, NEUROSCI L, 310(2-3), 2001, pp. 161-164
Bipolar cells (BCs) have antagonistic center-surround receptive field. Surr
ound illumination evokes depolarization in the OFF-type cone BC, and hyperp
olarization in the rod BC and the ON-type cone BC. Surround illumination re
duces gamma-aminobutyric acid (GABA) release from horizontal cells. If GABA
hyperpolarize BCs, the polarity of the GABA-induced effect agrees with the
light-evoked surround response in the OFF-type BC, but contradicts in the
rod BC and the ON-type cone BC. Immunohistochemical study of the Cl- transp
orter of BCs has suggested that the intracellular Cl- concentration is diff
erent among BC subtypes. We examined the reversal potential of GABA-induced
current of BCs using gramicidin-perforated patch clamp technique in the mo
use retina, and found that GABA depolarizes rod BC and hyperpolarizes cone
BCs. Our results are consistent with the GABAergic input to rod BC dendrite
. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.