Ca(2+)-dependent Cl- current at the presynaptic terminals of goldfish retinal bipolar cells

Neurosci Res. 1995 Oct;23(3):297-303. doi: 10.1016/0168-0102(95)00955-8.


In ON-type bipolar cells dissociated from the goldfish retina, a slowly declining inward current (Itail) was observed after the termination of depolarizing voltage step commands, during which a Ca2+ current was elicited. The properties of Itail were investigated under the whole-cell voltage clamp. Introduction of the membrane permeant Ca2+ chelator, BAPTA/AM, into the cell suppressed Itail, indicating that Itail was activated by the increase of intracellular free Ca2+ concentration ([Ca2+]i). The major component of Itail was identified as the Ca(2+)-dependent Cl- current (ICl(Ca)), since the reversal potential of Itail was almost identical to the Cl- equilibrium potential at various extracellular Cl- concentrations ([Cl-]o). The contribution of the Na+/Ca2+ exchanger current to Itail was very small. ICl(Ca) was partially suppressed by 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS) when it was locally applied to the axon terminal but not to the cell body region, suggesting that Ca(2+)-dependent Cl- channels were localized to the axon terminal. The relationship between the peak amplitude of ICl(Ca) and the amount of charge carried by the Ca2+ current was almost linear at levels less than ca. 50 pC, but became saturated at a higher Ca2+ charge.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / physiology*
  • Chloride Channels / drug effects*
  • Goldfish
  • Membrane Potentials / physiology
  • Presynaptic Terminals / physiology*
  • Retina / physiology*
  • Time Factors


  • Chloride Channels
  • Calcium