title: Taurine regulation of voltage-gated channels in retinal neurons.
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.
authors: Department of Biomedical Science, Florida Atlantic University, Boca Raton, FL 33431, USA. matt.rowan@mpfi.org
authors: Matthew J M
authors: MJ
authors: Rowan
authors: Simon
authors: S
authors: Bulley
authors: Lauren A
authors: LA
authors: Purpura
authors: Harris
authors: H
authors: Ripps
authors: Wen
authors: W
authors: Shen
mesh_terms: D000557:Ambystoma / Q000378:metabolism; D000818:Animals; D015220:Calcium Channels / Q000378:metabolism*; D020746:Calcium Channels, L-Type / Q000378:metabolism; D020864:Calcium Channels, N-Type / Q000378:metabolism; D024642:Potassium Channels, Voltage-Gated / Q000378:metabolism*; D011493:Protein Kinase C; D018094:Receptors, Metabotropic Glutamate / Q000378:metabolism; D051245:Retinal Bipolar Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D055351:Retinal Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013654:Taurine / Q000494:pharmacology*
chemical_list: D015220:Calcium Channels; D020746:Calcium Channels, L-Type; D020864:Calcium Channels, N-Type; D024642:Potassium Channels, Voltage-Gated; D018094:Receptors, Metabotropic Glutamate; D013654:Taurine; D011493:Protein Kinase C
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