ADENOSINE-INDUCED SLOW IONIC CURRENTS IN THE XENOPUS OOCYTE
ADENOSINE-INDUCED SLOW IONIC CURRENTS IN THE XENOPUS OOCYTE
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DOI：
10.1038/298572a0
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发表时间：
1982-01-01
期刊：
影响因子：
64.8
通讯作者：
LASS, Y
中科院分区：
文献类型：
--
作者：
LOTAN, I;DASCAL, N;LASS, Y
腺苷及其5′-磷酸化同源物在可兴奋组织中引起特异性膜介导反应1，2。现有数据表明，由于超极化而发生靶细胞的抑制3，4，并且在某些制剂中发现了ATP的复合效应（兴奋和抑制）5，6。然而，嘌呤能介导的反应的离子机制还没有研究标准的细胞内电压钳技术。最近，我们在异种卵母细胞中发现了嘌呤能受体，这是一种经过严格的电生理学和生物化学研究的明确的巨细胞。我们在这里报告说，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）瞬时电流，随后是涉及K+离子的稳定超极化（H）电流。D电流的相对效价顺序为ATP → ADP > AMP →腺苷; H电流的相对效价顺序相反。
Adenosine and its 5′-phosphorylated congeners evoke specific membrane-mediated responses in excitable tissues1,2. Available data suggest that inhibition of the target cell occurs due to hyperpolarization3,4, and in some preparations a compound effect of ATP (excitation and inhibition) has been found5,6. 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 theXenopusoocyte, a well defined giant cell amenable to rigorous electrophysiological7and biochemical8studies. 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≃ ADP > AMP ≃ adenosine; this order was reversed for the H current.