Characteristics Of The ATP-activated Current And Its Modulation In Xenopus Oocytes

PartⅠCharacteristics of the ATP-activated current and effect of pH change on the current in Xenopus OocytesOBJECTIVE: To investigate the effects of pH change on ATP-activated current(IATP)and the mechanism.METHODS: Two-electrode voltage clamp technique was used to record the ATP-activated current in healthy Xenopus oocytes.RESULTS: The experimental results showed that all the healthy oocytes appeared to be sensitive to ATP (10-3mol/L) with an characteristic current in a concentration–dependent manner when pH value is 7.4. The current include three parts: fast inward current, slow inward current and slow outward current. The amplitude of IATP decreased when pH of extracellular fluid was adjusted to 6.0 or 5.5, and among the three parts of IATP, D1 current was inhibited most obviously. When P2Y receptor was blocked by the application of G-protein inhibitor in cell, there was little effect on D1 current while D2 current decreased obviously. In contrast, D1 current reduced greatly if P2X receptor antagonist was used outside cell.CONCLUSION: The results suggested that pH decreasing inhibited the IATP of Xenopus oocytes mainly in a manner of affecting P2X.