title: Transport and function of chloride in vascular smooth muscles.
abstract: This review summarizes the current knowledge of Cl(-) transport in vascular smooth muscle cells (VSMCs). VSMCs accumulate Cl(-) intracellularly using two secondary-active transport mechanisms. The Cl(-) equilibrium potential is more positive than the resting membrane potential enabling Cl(-) to be a depolarizing ion upon activation of a Cl(-) conductance. Cl(-) currents are involved in different vascular responses suggesting a number of different Cl(-) channels. All known Cl(-) channel families, with the exception of the GABA-/glycine-receptor family, have been identified in VSMCs. At least one member of the voltage-activated ClC family - ClC-3 - has been suggested to be involved in myogenic constriction, in cell proliferation and to have an anti-apoptotic action. The cystic fibrosis transmembrane conductance regulator is also demonstrated in VSMCs. The molecular identity of the major anion conductance in VSMCs - a Ca(2+)-activated Cl(-) current - is uncertain. Several candidates have been suggested with bestrophin and TMEM16 protein families the current favorites. Specific pharmacological tools are lacking for Cl(-) channels but recent molecular biology developments have made selective gene manipulations possible. A continuing quest within the vascular research field is to explicitly demonstrate the coupling between a putative channel protein and an endogenous Cl(-) current and the importance of these for specific functions.
authors.affiliation: Department of Biomedicine, Aarhus University, Aarhus, Denmark. vvm@fi.au.dk
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Matchkov
authors.forename: Vibeke
authors.initials: V
authors.lastname: Secher Dam
authors.forename: Donna M Briggs
authors.initials: DM
authors.lastname: Bødtkjer
authors.forename: Christian
authors.initials: C
authors.lastname: Aalkjær
mesh_terms: D000818:Animals; D001692:Biological Transport; D049109:Cell Proliferation; D018118:Chloride Channels / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism*; D006439:Hemodynamics; D006801:Humans; D015640:Ion Channel Gating; D008564:Membrane Potentials; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D014661:Vasoconstriction
chemical_list: D018118:Chloride Channels; D002712:Chlorides