Zubov A N, Pisareva L N
Institute of Cytology, Russian Academy of Sciences, St. Petersburg.
Tsitologiia. 1997;39(7):601-11.
The application of ATP in micromolar concentrations to the macrophages results in a biphasic response in the form of the short-time depolarization followed by a rather long hyperpolarization, the corresponding inward and outward macroscopic currents being observed. The ATP-induced hyperpolarization is accompanied by changes in current kinetics, I/V-curves pattern and shifting in the reversal potential. Such changes may be explained by a supposition that ATP activates an additional fraction of potassium channels with characteristics other than those in cells with initially low value of membrane potential. The data available are suggestive that in resting cells the inward rectification potassium conductance may dominate, whereas during ATP-induced hyperpolarization a certain type of Ca(2+)-dependent potassium conductance prevails. A rather high membrane potential in some part of macrophages, not treated with ATP, may be attributed to the latter type of conductance.
将微摩尔浓度的ATP应用于巨噬细胞会导致双相反应，表现为短时间的去极化，随后是相当长的超极化，并观察到相应的内向和外向宏观电流。ATP诱导的超极化伴随着电流动力学、I/V曲线模式的变化以及反转电位的偏移。这些变化可以通过这样一种假设来解释，即ATP激活了一部分具有不同于初始膜电位值较低的细胞中钾通道特性的钾通道。现有数据表明，在静息细胞中，内向整流钾电导可能占主导，而在ATP诱导的超极化过程中，某种类型的钙依赖性钾电导占优势。在未用ATP处理的巨噬细胞的某些部分中相当高的膜电位可能归因于后一种电导类型。
