Taurine regulation of voltage-gated channels in retinal neurons.

Matthew J M Rowan, Simon Bulley, Lauren A Purpura, Harris Ripps, Wen Shen

Advances in experimental medicine and biology 2013

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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.

Citation

Matthew J M Rowan, Simon Bulley, Lauren A Purpura, Harris Ripps, Wen Shen. Taurine regulation of voltage-gated channels in retinal neurons. Advances in experimental medicine and biology. 2013;775:85-99