Comparison of effects of PKA catalytic subunit on Ih and calcium channel currents in rat dorsal root ganglion cells
Comparison of effects of PKA catalytic subunit on Ih and calcium channel currents in rat dorsal root ganglion cells
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DOI：
10.2220/biomedres.28.177
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发表时间：
2007-08-01
影响因子：
1.2
通讯作者：
Kitamura, Naoki
中科院分区：
文献类型：
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作者：
Komagiri, You;Kitamura, Naoki
我们研究了PKA诱导的磷酸化是否参与了大鼠背根神经节（DRG）细胞超极化激活电流（I-h）的调节。我们研究了PKA的催化亚基（PKAc）对I-h的影响，并证实了PKAc对Ba 2+（I-Ba）携带的Ca 2+通道电流的影响，在相同的神经元中作为PKA活性的阳性对照。开始记录后，I-Ba的振幅逐渐降低（rundown）。细胞内ATP的应用减少了I-Ba的流失，并诱导I-h激活的去极化移位。公钥基础设施部分逆转了前者，但后者没有受到影响。PKAc的细胞内应用也防止了I-Ba的流失，并且冈田酸（OA）增强了这种效果。PKAc和OA的组合应用并没有改变I-h的电生理特性，但在相同的神经元中观察到对I-Ba的增强作用。除了PKAc和OA的应用程序2 mM ATP没有导致在一个额外的增强I-Ba，但移动的激活曲线的I-h的积极。上述结果提示，PKA诱导的磷酸化不参与I-h对大鼠DRG神经元的调节机制。
We investigated whether PKA-Induced phosphorylation was involved in regulation of hyperpolarization-activated current (I-h) in rat dorsal root ganglion (DRG) cells. We examined the effect of the catalytic subunit of PKA (PKAc) on I-h and confirmed an effect of PKAc on Ca2+ channel currents carried by Ba2+ (I-Ba) in identical neurons as a positive control of PKA activity. After the start of recording, amplitudes of I-Ba gradually decreased (rundown). An intracellular application of ATP reduced the rundown of I-Ba and induced a depolarizing shift of I-h activation. The former was partially reversed by PKI but the latter was not affected. An intracellular application of PKAc also prevented the rundown of I-Ba and this effect was potentiated by okadaic acid (OA). The application of PKAc and OA in combination did not change the electrophysiological properties of I-h although a potentiating effect on I-Ba was observed in the same neurons. The application of 2-mM ATP in addition to PKAc and OA did not result in an additional potentiation of I-Ba, but shifted the activation curve of I-h positively. These results suggested that PKA-induced phosphorylation was not involved in the modulatory mechanisms of I-h in rat DRG neurons.