Lotan I, Dascal N, Cohen S, Lass Y
Nature. 1982 Aug 5;298(5874):572-4. doi: 10.1038/298572a0.
Adenosine and its 5'-phosphorylated congeners evoke specific membrane-mediated responses in excitable tissues. Available data suggest that inhibition of the target cell occurs due to hyperpolarization, and in some preparations a compound effect of ATP (excitation and inhibition) has been found. However, the ionic mechanism of the purinergic-mediated response has not been studied by standard intracellular voltage-clamping techniques. Recently, we have discovered purinergic receptors in the Xenopus oocyte, a well defined giant cell amenable to rigorous electrophysiological and biochemical studies. We report here that in these cells, adenosine-induced slow membrane responses consisted of an early depolarizing (D) transient current carried by Cl ions, followed by a steady hyperpolarizing (H) current involving K+ ions. The relative potency sequence for the D current was ATP congruent to ADP greater than AMP congruent to adenosine; this order was reversed for the H current.
腺苷及其5'-磷酸化同系物在可兴奋组织中引发特定的膜介导反应。现有数据表明，靶细胞的抑制是由于超极化引起的，并且在一些制剂中发现了ATP的复合效应（兴奋和抑制）。然而，嘌呤能介导反应的离子机制尚未通过标准的细胞内电压钳技术进行研究。最近，我们在非洲爪蟾卵母细胞中发现了嘌呤能受体，这是一种适合进行严格电生理和生化研究的明确的巨细胞。我们在此报告，在这些细胞中，腺苷诱导的缓慢膜反应包括由Cl离子携带的早期去极化（D）瞬态电流，随后是涉及K +离子的稳定超极化（H）电流。D电流的相对效力顺序为ATP等同于ADP大于AMP等同于腺苷；H电流的顺序则相反。
