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ȣ - 520143 1 |
| Protein kinase C inhibitor staurosporine reduce the inactivation process of voltage-dependent sodium channels in rabbit atrial myocytes |
| ¹ 인제대학교 의과대학 부산백병원 심장내과학교실, ² 인제대학교 심혈관 및 대사질환 연구센터, FIRST 미토콘드리아 연구그룹, ³ 인제대학교 의과대학 생리학교실 미토콘드리아생체신호-국가지정연구실 |
| 박원선² ³, 김성만¹ ² , 최성우² ³, 김도형² ³ , 고은아 ² ³, 김나리² ³ , 염재범² ³ , 한진² ³ , 박영진¹ , 노은지¹ , 한양천¹ , 김기훈¹ , 설상훈¹ , 양태현¹ , 김대경¹ , 김두일¹ , 김동수¹ ² |
In this study, the effect of staurosporine (ST), a potent protein kinase C (PKC) inhibitor, on Na+ current (INa) was examined by whole-cell patch recording in rabbit atrial myocytes. The most prominent ST effect was a slowing of INa inactivation and 1 mM ST reduced amplitude of INa about 33%. ST decreased INa at all potentials and slowed the INa inactivation in a dose-dependent manner, with a Kd value of 1.107 ± 0.162 µM. ST did not change the recovery kinetics and show use-dependence. However, the activation and the steady-state inactivation curves were shifted toward more negative potentials (-5.5 and –5.1 mV, respectively). Two other PKC inhibitors, GF 109203X (1 µM) and chelerythrine (3 µM), did not show a slowing effect on INa inactivation. In conclusion, our results indicate that the slowing of INa inactivation by ST seems not to be through blockade of PKC rather to act directly on the Na+ channels, and the direct blocking effects of ST on the Na+ channel should be taken into consideration when ST is used in functional studies of ion channel modulation by protein phosphorylation.
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