Electrophysiological evidence for an ATP-gated ion channel in the principal cells of the frog skin epithelium.

摘要: In the present study we investigated effects of adenosine 5'-triphosphate (ATP) on Na+ transport in frog skin epithelium. An experimental set-up was constructed to allow simultaneous measurement transport, measured as amiloride-sensitive short circuit current (Isc), and free cytosolic Ca2+ concentration ([Ca2+]i) with Ca(2+)-sensitive dye fura-2. The cell potential (Vsc) microelectrodes. Addition ATP (100 micrM) basolateral solution resulted a fast transient decrease Isc followed by slower increase [Ca2+]i. Microelectrode measurements showed that primary response, i.e. decline accompanied depolarisation, return control value. independent; treatment thapsigargin Ca(2+)-free solutions abolished but did not influence transient. secondary slow current, depolarisation cell. Measurements apical permeability this due an opening or activation channels. These data show causes initial drop secondary, long-lasting absorption. ability cause is independent Ca2+, it caused P2Y-type receptors tissue. intracellular indicate non-selective cation channels, suggesting P2X-type receptors.