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首页> 外文期刊>American Journal of Physiology >P2X receptors in mouse Leydig cells.
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P2X receptors in mouse Leydig cells.

机译：小鼠Leydig细胞中的P2X受体。

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ATP-activated currents were studied in Leydig cells of mice with the patch-clamp technique. Whole cell currents were rapidly activating and slowly desensitizing (55% decrement from the peak value on exposure to 100 microM ATP for 60 s), requiring 3 min of washout to recover 100% of the response. The concentration-response relationships for ATP, adenosine 5'-O-(3-thiotriphosphate) (ATPgammaS), and 2-methylthio-ATP (2-MeS-ATP) were described by the Hill equation with a concentration evoking 50% of maximal ATP response (K(d)) of 44, 110, and 637 microM, respectively, and a Hill coefficient of 2. The order of efficacy of agonists was ATP >or= ATPgammaS > 2-MeS-ATP > 2',3'-O-(4-benzoylbenzoyl)-ATP (BzATP). alphabeta-Methylene-ATP (alphabeta-MeATP), GTP, UTP, cAMP, and adenosine were ineffective. Suramin and pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS) blocked the responses in a concentration-dependent manner. The ATP-activated currents were dependent on extracellular pH, being maximal at pH6.5 and decreasing with both acidification and alkalinization (apparent dissociation constant (pK(a)) of 5.9 and 7.4, respectively). The whole cell current-voltage relationship showed inward rectification and reversed near 0 mV. Experiments performed in bi-ionic conditions for measurement of reversal potentials showed that this channel is highly permeable to calcium [permeability (P)(Ca)/P(Na) = 5.32], but not to chloride (P(Cl)/P(Na) = 0.03) or N-methyl-D-glucamine (NMDG) (P(NMDG)/P(Na) = 0.09). Unitary currents recorded in outside-out patches had a chord conductance of 27 pS (between -90 and -50 mV) and were inward rectifying. The average current passing through the excised patch decreased with time [time constant (tau) 13 s], resembling desensitization of the macroscopic current. These findings indicate that the ATP receptor present in Leydig cells shows properties most similar to those of cloned homomeric P2X(2).
机译：用膜片钳技术在小鼠的Leydig细胞中研究了ATP激活的电流。全细胞电流迅速激活并缓慢脱敏（从暴露于100 microM ATP 60 s时的峰值下降55％），需要3分钟的洗脱时间才能恢复100％的响应。通过Hill方程描述了ATP，腺苷5'-O-（3-硫代三磷酸）（ATPgammaS）和2-甲硫基-ATP（2-MeS-ATP）的浓度-响应关系，其浓度最大为50％ ATP响应（K（d））分别为44、110和637 microM，希尔系数为2。激动剂的功效顺序为ATP>或= ATPgammaS> 2-MeS-ATP> 2'，3' -O-（4-苯甲酰基苯甲酰基）-ATP（BzATP）。字母-亚甲基-ATP（alphabeta-MeATP），GTP，UTP，cAMP和腺苷无效。苏拉明和磷酸吡ido醛-6-偶氮苯基-2'，4'-二磺酸（PPADS）以浓度依赖性方式阻断了反应。 ATP激活的电流取决于细胞外pH，在pH6.5时最大，并随着酸化和碱化而降低（表观解离常数（pK（a））分别为5.9和7.4）。整个电池的电流-电压关系显示向内整流，并在0 mV附近反转。在双离子条件下进行反向电位测量的实验表明，该通道对钙具有高渗透性[渗透性（P）（Ca）/ P（Na）= 5.32]，但对氯离子（P（Cl）/ P（ Na）= 0.03）或N-甲基-D-葡萄糖胺（NMDG）（P（NMDG）/ P（Na）= 0.09）。从外而外的补丁中记录的单位电流的弦电导为27 pS（在-90和-50 mV之间），并且向内整流。通过切下的小片的平均电流随时间[时间常数（τ）13 s]减小，类似于宏观电流的脱敏。这些发现表明Leydig细胞中存在的ATP受体显示出与克隆的同型P2X（2）最相似的特性。

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