title: Characterisation of a human acid-sensing ion channel (hASIC1a) endogenously expressed in HEK293 cells.
abstract: Acid-sensing ion channels (ASICs) are a new and expanding family of proton-gated cation (Na+/Ca2+) channels that are widely expressed in sensory neurons and the central nervous system. Their distribution suggests that they may play a critical role in the sensation of the pain that accompanies tissue acidosis and may also be important in detecting the subtle pH variations that occur during neuronal signalling. Here, using whole-cell patch-clamp electrophysiology and reverse transcriptase-polymerase chain reaction (RT-PCR), we show that HEK293 cells, a commonly used cell line for the expression and characterisation of many ion channels, functionally express an endogenous proton-gated conductance attributable to the activity of human ASIC1a. These data therefore represent the first functional characterisation of hASIC1 and have many important implications for the use of HEK293 cells as a host cell system for the study of ASICs, vanilloid receptor-1 and any other proton-gated channel. With this latter point in mind we have devised a simple desensitisation strategy to selectively remove the contribution of hASIC1a from proton-gated currents recorded from HEK293 cells expressing vanilloid receptor-1.
authors.affiliation: Neuroscience Research, GlaxoSmithKline Pharmaceuticals, New Frontiers Science Park (North), Harlow, Essex, CM19 5AW, UK. Martin_J_Gunthorpe@gsk.com
authors.forename: M J
authors.initials: MJ
authors.lastname: Gunthorpe
authors.forename: G D
authors.initials: GD
authors.lastname: Smith
authors.forename: J B
authors.initials: JB
authors.lastname: Davis
authors.forename: A D
authors.initials: AD
authors.lastname: Randall
mesh_terms: D062565:Acid Sensing Ion Channels; D000584:Amiloride / Q000494:pharmacology; D002460:Cell Line; D004232:Diuretics / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015640:Ion Channel Gating; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009619:Nociceptors / Q000378:metabolism; D018408:Patch-Clamp Techniques; D011522:Protons; D011955:Receptors, Drug / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015222:Sodium Channels / Q000235:genetics / Q000378:metabolism*; D050916:TRPV Cation Channels
chemical_list: C568266:ASIC1 protein, human; C112231:ASIC3 protein, human; D062565:Acid Sensing Ion Channels; D004232:Diuretics; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D011522:Protons; D011955:Receptors, Drug; D015222:Sodium Channels; D050916:TRPV Cation Channels; C494484:TRPV1 receptor; D000584:Amiloride