title: Modulation of calcium channels by taurine acting via a metabotropic-like glycine receptor.
abstract: Taurine is one of the most abundant free amino acids in the central nervous system, where it displays several functions. However, its molecular targets remain unknown. It is well known that taurine can activate GABA-A and strychnine-sensitive glycine receptors, which increases a chloride conductance. In this study, we describe that acute application of taurine induces a dose-dependent inhibition of voltage-dependent calcium channels in chromaffin cells from bovine adrenal medullae. This taurine effect was not explained by the activation of either GABA-A, GABA-B or strychnine-sensitive glycine receptors. Interestingly, glycine mimicked the modulatory action exerted by taurine on calcium channels, although the acute application of glycine did not elicit any ionic current in these cells. Additionally, the modulation of calcium channels exerted by both taurine and glycine was prevented by the intracellular dialysis of GDP-β-S. Thus, the modulation of voltage-dependent calcium channels by taurine seems to be mediated by a metabotropic-like glycinergic receptor coupled to G-protein activation in a membrane delimited pathway.
authors.affiliation: Instituto Teófilo Hernando, Univ. Autónoma de Madrid, Av. Arzobispo Morcillo 4, 28029 Madrid, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Albiñana
authors.forename: S
authors.initials: S
authors.lastname: Sacristán
authors.forename: R
authors.initials: R
authors.lastname: Martín del Río
authors.forename: J M
authors.initials: JM
authors.lastname: Solís
authors.forename: J M
authors.initials: JM
authors.lastname: Hernández-Guijo
mesh_terms: D000818:Animals; D015220:Calcium Channels / Q000378:metabolism*; D002417:Cattle; D019439:Chromaffin Cells / Q000187:drug effects / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism; D005998:Glycine / Q000494:pharmacology; D015640:Ion Channel Gating / Q000187:drug effects; D008562:Membrane Glycoproteins / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism; D018080:Receptors, GABA-B / Q000378:metabolism; D018009:Receptors, Glycine / Q000378:metabolism*; D013654:Taurine / Q000494:pharmacology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism; D000099247:Taurine Transporters
chemical_list: D015220:Calcium Channels; D019204:GTP-Binding Proteins; D005998:Glycine; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D018080:Receptors, GABA-B; D018009:Receptors, Glycine; D013654:Taurine; D005680:gamma-Aminobutyric Acid; D000099247:Taurine Transporters