Micro-electrode measurements and functional aspects of chloride activity in cyprinid fish retina: extracellular activity and intracellular activities of L- and C-type horizontal cells

Vision Res. 1987;27(9):1481-9. doi: 10.1016/0042-6989(87)90157-x.


Extracellular Cl- activity and intracellular Cl- activities of luminosity and biphasic-chromaticity type horizontal cells were measured in freshly isolated, non-superfused roach retinae using double-barrelled Cl- -sensitive micro-electrodes. The extracellular Cl- activity in dark-adapted retinae was found to have a surprisingly wide range (54-143 mM), although in a given preparation it was extremely constant. The mean intracellular Cl- activities of both types of horizontal cell were identical (47 mM), and this value was significantly greater than that required for "passive distribution" i.e. Cl- equilibrium potentials were 11-12 mV more positive than respective membrane resting potentials in the dark. In the presence of 10 microM dopamine, however, the difference between the Cl- equilibrium potential and the membrane resting potential was abolished, consistent with the hypothesis that dopamine increases Cl- conductance, presumably at the interplexiform cell synapse onto horizontal cells. In turn, it is suggested that a functional consequence of this pathway is to modulate the input impedances of the horizontal cells, and hence their sensitivity to light.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chlorides / physiology*
  • Cyprinidae / physiology*
  • Darkness
  • Dopamine / pharmacology
  • In Vitro Techniques
  • Light
  • Membrane Potentials
  • Microelectrodes
  • Retina / cytology
  • Retina / physiology*


  • Chlorides
  • Dopamine