title: Hypoosmotic- and pressure-induced membrane stretch activate TRPC5 channels.
abstract: Transient receptor potential (TRP) channels mediate a wide array of sensory functions. We investigated the role of TRPC5, a poorly characterized channel widely expressed in the central and peripheral nervous system, as a potential osmosensory protein. Here we show that hypoosmotic stimulation activates TRPC5 channels resulting in a large calcium influx. The response to osmotically induced membrane stretch is blocked by GsMTx-4, an inhibitor of stretch activated ion channels. Direct hypoosmotic activation of TRPC5 is independent of phospholipase C function. However, the osmotic response is inhibited in a cell line in which PIP(2) levels are reduced by regulated overexpression of a lipid phosphatase. The response was restored by increasing intracellular PIP(2) levels through the patch pipette. The mechano-sensitivity of the channel was probed in the whole-cell configuration by application of steps of positive pressure through the patch pipette. Pressure-induced membrane stretch also activated TRPC5 channels, suggesting its role as a transducer of osmo-mechanical stimuli. We also demonstrated the expression of TRPC5 in sensory neurones which together with the osmo-mechanical characteristics of TRPC5 channels suggest its putative role in mechanosensory transduction events.
authors.affiliation: Instituto de Neurociencias de Alicante, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández. Av. Ramón y Cajal s/n. 03550 Sant Joan d'Alacant, Alicante, Spain. agomis@umh.es
authors.forename: Ana
authors.initials: A
authors.lastname: Gomis
authors.forename: Sergio
authors.initials: S
authors.lastname: Soriano
authors.forename: Carlos
authors.initials: C
authors.lastname: Belmonte
authors.forename: Félix
authors.initials: F
authors.lastname: Viana
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002217:Carbachol / Q000494:pharmacology; D002460:Cell Line; D002462:Cell Membrane / Q000502:physiology*; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D004963:Estrenes / Q000494:pharmacology; D005727:Ganglia, Spinal / Q000378:metabolism; D006624:Hippocampus / Q000378:metabolism; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D051379:Mice; D009997:Osmotic Pressure; D010455:Peptides / Q000494:pharmacology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism; D011312:Pressure; D011760:Pyrrolidinones / Q000494:pharmacology; D011984:Sensory Receptor Cells / Q000378:metabolism; D013111:Spider Venoms / Q000494:pharmacology; D013314:Stress, Mechanical; D050052:TRPC Cation Channels / Q000235:genetics / Q000502:physiology*; D019284:Thapsigargin / Q000494:pharmacology; D014162:Transfection; D012668:Trigeminal Ganglion / Q000378:metabolism; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors; D000099182:Phosphoinositide 5-Phosphatases
chemical_list: D002118:Calcium; D002217:Carbachol; D004963:Estrenes; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D010726:Phosphodiesterase Inhibitors; D010744:Phosphoric Monoester Hydrolases; D011760:Pyrrolidinones; D013111:Spider Venoms; D050052:TRPC Cation Channels; D019284:Thapsigargin; D010738:Type C Phospholipases; D000099182:Phosphoinositide 5-Phosphatases; C411249:MTx4 protein, Grammostola spatulata; C112021:Trpc5 protein, mouse; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione