title: TRP-Na(+)/Ca(2+) Exchanger Coupling.
abstract: Na(+)/Ca(2+) exchangers (NCXs) have traditionally been viewed principally as a means of Ca(2+) removal from non-excitable cells. However there has recently been increasing interest in the operation of NCXs in reverse mode acting as a means of eliciting Ca(2+) entry into these cells. Reverse mode exchange requires a significant change in the normal resting transmembrane ion gradients and membrane potential, which has been suggested to occur principally via the coupling of NCXs to localised Na(+) entry through non-selective cation channels such as canonical transient receptor potential (TRPC) channels. Here we review evidence for functional or physical coupling of NCXs to non-selective cation channels, and how this affects NCX activity in non-excitable cells. In particular we focus on the potential role of nanojunctions, where the close apposition of plasma and intracellular membranes may help create the conditions needed for the generation of localised rises in Na(+) concentration that would be required to trigger reverse mode exchange.
authors.affiliation: Institute for Science and Technology in Medicine, Keele University, Guy Hilton Research Centre, Thornburrow Drive, Hartshill, Stoke-on-Trent, ST4 7QB, UK.
authors.forename: Alan G S
authors.initials: AG
authors.lastname: Harper
authors.affiliation: Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK. sos10@cam.ac.uk.
authors.forename: Stewart O
authors.initials: SO
authors.lastname: Sage
mesh_terms: D002118:Calcium / Q000378:metabolism; D006801:Humans; D017136:Ion Transport; D012964:Sodium / Q000378:metabolism; D019831:Sodium-Calcium Exchanger / Q000378:metabolism*; D050052:TRPC Cation Channels / Q000378:metabolism*
chemical_list: D019831:Sodium-Calcium Exchanger; D050052:TRPC Cation Channels; D012964:Sodium; D002118:Calcium
keywords: Calcium entry; Na+/Ca2+ exchangers; Reverse mode NCX activity; Sodium entry; TRPC channels