title: The taurine transporter substrate guanidinoethyl sulfonate mimics the action of taurine on long-term synaptic potentiation.
abstract: Taurine is especially abundant in rodent brain where it appears to be involved in osmoregulation and synaptic plasticity mechanisms. The demonstration of a physiological role for taurine has been hampered by the difficulty in modifying taurine levels in most tissues, including the brain. We used an experimental strategy to reduce taurine levels, involving treatment with guanidinoethyl sulfonate (GES), a structural analogue of taurine that, among other properties, acts as a competitive inhibitor of taurine transport. GES delivered in the drinking water of rats for 1 month effectively reduced taurine levels in brain structures (hippocampus, cerebellum and cortex) and outside the brain (heart, muscle, kidney, liver and plasma) by between 50 and 80 %, depending on the tissue. This partial taurine depletion did not affect either basal synaptic transmission or the late phase of long-term potentiation (late-LTP) in hippocampal slices. In vivo microdialysis studies in the hippocampus revealed that GES treatment reduced extracellular taurine levels and the magnitude of taurine released in response to the application of either N-methyl-D-aspartate (NMDA) or a hypoosmotic solution, without affecting release mechanisms. Finally, we demonstrated in hippocampal slices that a brief GES application can mimic taurine action on the conversion of a decremental LTP into a perdurable late-LTP, concluding that GES might replace taurine function in some mechanisms such as those implicated in synaptic plasticity.
authors.affiliation: Servicio de Neurobiología-Investigación, Hospital Universitario Ramón y Cajal, IRYCIS, Ctra. de Colmenar Km 9, 28034, Madrid, Spain.|Instituto Cajal CSIC, Avda. Doctor Arce 37, 28002, Madrid, Spain.|CIBERNED, Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Luz M
authors.initials: LM
authors.lastname: Suárez
authors.affiliation: Unidad de Neurología Experimental, Hospital Universitario Ramón y Cajal, IRYCIS, 28034, Madrid, Spain.
authors.forename: María-Dolores
authors.initials: MD
authors.lastname: Muñoz
authors.affiliation: Servicio de Neurobiología-Investigación, Hospital Universitario Ramón y Cajal, IRYCIS, Ctra. de Colmenar Km 9, 28034, Madrid, Spain.|Department of Neurobiology, McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
authors.forename: José C
authors.initials: JC
authors.lastname: González
authors.affiliation: Depto. Fisiología, Facultad de Medicina, UCM, 28040, Madrid, Spain.
authors.forename: Julián
authors.initials: J
authors.lastname: Bustamante
authors.affiliation: Servicio de Neurobiología-Investigación, Hospital Universitario Ramón y Cajal, IRYCIS, Ctra. de Colmenar Km 9, 28034, Madrid, Spain.
authors.forename: Rafael Martín
authors.initials: RM
authors.lastname: Del Río
authors.affiliation: Servicio de Neurobiología-Investigación, Hospital Universitario Ramón y Cajal, IRYCIS, Ctra. de Colmenar Km 9, 28034, Madrid, Spain. jose.m.solis@hrc.es.
authors.forename: José M
authors.initials: JM
authors.lastname: Solís
mesh_terms: D000818:Animals; D006624:Hippocampus / Q000378:metabolism*; D017774:Long-Term Potentiation / Q000187:drug effects*; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013654:Taurine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000099247:Taurine Transporters
chemical_list: D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D013654:Taurine; D000099247:Taurine Transporters; C009558:taurocyamine
keywords: Glutamate; Nutrition; Osmoresistant; Osmosensitive; Rat