Fading and redound of P2X_2 currents at millimolar ATP concentrations caused by low pH

摘要

When ATP is applied at high concentrations (above 1 mM) to PC12 cells, it produces a rapidly desensitizing peak current followed by a rebound of the current after termination of the ATP application. We expressed P2X_2 receptors, which are thought to mediate the ATP currents of PC12 cells. in HEK293 cells and studied the effects of acidification on this 'fading and rebound' phenomenon. We found that the desensitization disappeared after adjusting the low pH (<5.0) of the millimolar ATP concentrations to a more physiological value (pH 7.3).