Synaptic transmission between photoreceptors and horizontal cells in the turtle retina

Science. 1974 Feb 1;183(4123):417-9. doi: 10.1126/science.183.4123.417.


Low calcium, high magnesium, and cobalt hyperpolarize the horizontal cell membrane and suppress the response to light, but only partially affect the response of receptor cells. These observations are consistent with the interpretation that a depolarizing transmitter is released by photoreceptors in darkness. The hyperpolarizing response to light of the horizontal cells would then result from a reduction in the amount of transmitter released.

MeSH terms

  • Action Potentials / drug effects
  • Animals
  • Calcium / pharmacology
  • Cobalt / pharmacology
  • In Vitro Techniques
  • Magnesium / pharmacology
  • Photic Stimulation
  • Photoreceptor Cells / physiology*
  • Retina / cytology
  • Retina / physiology*
  • Synaptic Transmission / drug effects*
  • Turtles


  • Cobalt
  • Magnesium
  • Calcium