Taurine regulation of voltage-gated channels in retinal neurons

Adv Exp Med Biol. 2013;775:85-99. doi: 10.1007/978-1-4614-6130-2_7.

Abstract

Taurine activates not only Cl(-)-permeable ionotropic receptors but also receptors that mediate metabotropic responses. The metabotropic property of taurine was revealed in electrophysiological recordings obtained after fully blocking Cl(-)-permeable receptors with an inhibitory "cocktail" consisting of picrotoxin, SR95531, and strychnine. We found that taurine's metabotropic effects regulate voltage-gated channels in retinal neurons. After applying the inhibitory cocktail, taurine enhanced delayed outward rectifier K(+) channels preferentially in Off-bipolar cells, and the effect was completely blocked by the specific PKC inhibitor, GF109203X. Additionally, taurine also acted through a metabotropic pathway to suppress both L- and N-type Ca(2+) channels in retinal neurons, which were insensitive to the potent GABA(B) receptor inhibitor, CGP55845. This study reinforces our previous finding that taurine in physiological concentrations produces a multiplicity of metabotropic effects that precisely govern the integration of signals being transmitted from the retina to the brain.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Ambystoma / metabolism
  • Animals
  • Calcium Channels / metabolism*
  • Calcium Channels, L-Type / metabolism
  • Calcium Channels, N-Type / metabolism
  • Potassium Channels, Voltage-Gated / metabolism*
  • Protein Kinase C
  • Receptors, Metabotropic Glutamate / metabolism
  • Retinal Bipolar Cells / cytology
  • Retinal Bipolar Cells / drug effects
  • Retinal Bipolar Cells / metabolism
  • Retinal Neurons / cytology
  • Retinal Neurons / drug effects*
  • Retinal Neurons / metabolism*
  • Signal Transduction / drug effects
  • Taurine / pharmacology*

Substances

  • Calcium Channels
  • Calcium Channels, L-Type
  • Calcium Channels, N-Type
  • Potassium Channels, Voltage-Gated
  • Receptors, Metabotropic Glutamate
  • Taurine
  • Protein Kinase C