Time, voltage and ionic concentration dependence of rectification of h‐erg expressed in Xenopus oocytes

FEBS Letters

Liu, Shuguang¹  Rasmusson, Randall L.¹  Wang, Shimin¹  Strauss, Harold C.¹  Morales, Michael J.¹ 

[1] The Departments of Medicine, Biomedical Engineering and Pharmacology, Duke University Medical Center, Durham, NC 27708-0281, USA

关键词: Potassium;    Delayed rectifier;    Repolarization;    Cardiac myocyte;   

DOI  :  10.1016/0014-5793(96)00570-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The rapid delayed rectifier, I_Kr is believed to have h-erg (uman ther-à-go-go elated ene) as its molecular basis. A recent study has shown that rectification of h-erg involves a rapid inactivation process that involves rapid closure of the external mouth of the pore or C-type inactivation. We measured the instantaneous current to voltage relationship for h-erg channels using the saponin permeabilized variation of the cut-open oocyte clamp technique. In contrast to C-type inactivation in other voltage-gated K⁺ channels, the rate of inactivation was strongly voltage dependent at depolarized potentials. This voltage dependence could be modulated independently of activation by increasing [K⁺]_o from 2 to 98 mM. These results suggest that inactivation of h-erg has its own intrinsic voltage sensor.

【 授权许可】

Unknown