Regulation of by protein kinases of CFTR chloride current and the acidic pH-activated chloride current in cardiac myocytes

1.这是众所周知的，因为提取物酸中毒调制在异常和非异常细胞中有许多类型的离子通道。最近，一种新颖的Cl-电流，它被发现在大鼠睾丸细胞中的酸性pH值被激活。类似的当前值（I_<Cl.pH>was在小鼠和几内亚猪中找到了肠道myocytes）。当酸性溶液应用于细胞时，I_<Cl.pH>出现在1分钟内，增加了研究生，达到了5分钟内的最大值。在对比度下，当前迅速消失（&lt;1分钟）在正常pH值（7.4）上恢复了溶液的正常值（7.4）。I_<Cl.pH>was在pH值/相关标记中激活，在pH值6.0的半最大激活。I_<Cl.pH>exhibited a weak time·dependent activation， the current amplitude slightly increasing during depolarizing step pulses。I·V relationship of I_<Cl.pH>showed a strong outward rectification under symmetManagement [Cl-] conditions。这种电流的阴离子选择被估计是我&gt; Cl-&gt;Asp。我向你展示的药理学研究 ... More _<Cl.pH>被几种Cl-Channel阻断器（DIDS、极简酸和甘油Cl-amide）抑制。Thus，I_<Cl.pH>difference from其他心脏病Cl-current的属性（体积·调节的Cl-current，不允许重复的Cl-current， Ca^&lt;2+&gt;·激活的Cl-current或CFTR current）。I_<Cl.pH>可以在病理条件下发挥作用的潜在作用，例如与化学相关的冠心病。提取物ATP对CFTR Cl当前（I^&lt;Cl，PKA&gt;）的β-肾上腺活性的影响是在几内亚猪肠道细胞中进行的。细胞首次暴露为0.02-1 μM异丙二烯醇（ISO），激活I_&lt;Cl，PKA&gt; 3分钟，然后在ISO的存在中达到1.100 μM ATP。ATP发现有潜力I_&lt;Cl，PKA&gt;，在大多数细胞检查中。在大约2/<3>他们的情况下，这个潜力是由一个抑制因素预先确定的，I_&lt;Cl，PKA&gt;改变在一个双重标准中。初始抑制应该是由ATP刺激P1-受体，但由于抑制是由这种受体类型的阻滞剂引起的。ATP含量为50 μM，平均水平为50 μ M，结果在ISO单独激活的Cl-conductance（0.02-1μM）中增加了1.3个增量。ADP和ATPγS在I_&lt;Cl，PKA&gt;上的影响与ATP相似，而AMP和腺苷从未可能增加I_&lt;Cl，PKA&gt;。因此，这种潜力被归因于P2-Purinoceptors的刺激。PD埠（0.5 μM）、an activator of PKC、facilitated I_&lt;Cl、PKA&gt;、and in the presence of PD埠ATP did not further potentiate I_&lt;Cl、PKA&gt;。When BIM （0.2 μM）， an inhibitor of PKC， was present， ATP did not facilitate I_&lt;Cl，PKA&gt;。这些发现建议在观察到的ATP操作中使用PKC的影响。如果ATP在ISO的存在中被移除，那么可能的ICl，PKA被移除（恢复）只是缓慢，如果ATP在这个缓慢恢复阶段被应用，那么亚序当前潜力就会减弱。由于ATP对P_2纯化剂的刺激，导致I_&lt;Cl，PKA&gt;的β-肾上腺激活通过PKC激活，这可能出现在ATP清除后的几分钟内。Less（低）

1. It is well known that extracellular acidosis modulates many types of ion channels in excitable and non-excitable cells. Recently, a novel Cl- current that is activated by acidic pH has been found in rat sertoli cells. A similar current (I_<Cl.pH> was found in ventricular myocytes from mouse and guinea pig. When acidic solution was applied to the cells, I_<Cl.pH> appeared with a delay of 〜1 min, increased gradually, and reached a maximum in 〜5 min. In contrast, the current disappeared rapidly (<1 min) upon resumption of the solution with normal pH (7.4). I_<Cl.pH> was activated in a pH・dependent manner, with a half maximal activation at about pH 6.0. I_<Cl.pH> exhibited a weak time・dependent activation, the current amplitude slightly increasing during depolarizing step pulses. I・V relationship of I_<Cl.pH> showed a strong outward rectification under symmetrical [Cl-] conditions. The anion selectivity of this current was estimated to be I>Cl->Asp. Pharmacological studies showed that I … More _<Cl.pH> was inhibited by several Cl- channel blockers (DIDS, niflumic acid and gliben Cl-amide). Thus, the properties of I_<Cl.pH> differ from those of other cardiac Cl- currents (volume・regulated Cl- current, inwardly rectifying Cl- current, Ca^<2+>・activated Cl- current or CFTR current). I_<Cl.pH> may play a role in the control of the action potential duration under pathological conditions, such as ischemia-related cardiac acidosis.2. The effects of extracellular ATP on β-adrenergic activation of CFTR Cl current (I^<Cl,PKA>) were examined in guinea-pig ventricular cells. The cells were initially exposed to 0.02-1 μM isoproterenol (ISO) for 〜3 min to activate I_<Cl,PKA>, and then to 1.100 μM ATP in the presence of ISO. ATP was found to potentiate I_<Cl,PKA>, in most cells examined. In about 2/<3> of them, however, the potentiation was preceded by an inhibition, I_<Cl,PKA> changing in a biphasic manner. The initial inhibition was due to stimulation of P1-purinoceptor by ATP, since the inhibition was attenuated by the blockers of this receptor type. With 50 μM ATP, the potentiation, on average, resulted in a 1.3 fold increase of the Cl- conductance activated by ISO alone (0.02-1μM). The effects of ADP and ATPγS on I_<Cl,PKA> were similar to those of ATP, while AMP and adenosine never potentiated I_<Cl,PKA>. Thus the potentiation was attributed to a stimulation of P2-purinoceptors. PDBu (0.5 μM), an activator of PKC, facilitated I_<Cl,PKA>, and in the presence of PDBu ATP did not further potentiate I_<Cl,PKA>. When BIM (0.2 μM), an inhibitor of PKC, was present, ATP did not facilitate I_<Cl,PKA>. These findings suggested involvement of PKC in the observed ATP action. When ATP was removed in the presence of ISO, the potentiated ICl,PKA decreased (recovered) only slowly, and, if ATP was reapplied during this slowly recovering phase, the subsequent current potentiation was weak. Thus the stimulation of P_2 purinoceptors by ATP facilitates the β-adrenergic activation of I_<Cl,PKA> through PKC activation, and this potential appears to persist for several min after removal of ATP. Less