Stationary Outward and Transient Ca2⁢-Dependent Currents in Hamster Oocytes

• 영문명: Stationary Outward and Transient Ca^2⁢-Dependent Currents in Hamster Oocytes
• 발행기관: 대한생리학회-대한약리학회
• 저자명: Yang-Mi Kim Jae-Hee Han Jong-Su Kim Seong-Geun Hong
• 간행물 정보: 『The Korean Journal of Physiology & Pharmacology』제4권 제5호, 403~408쪽, 전체 6쪽
• 주제분류: 의약학 > 의학일반
• 파일형태: PDF
• 발행일자: 2000.01.01

영문 초록

The outward currents elicited in hamster eggs by depolarizing pulses were studied. The currents appeared to comprise at least two components, a transient outward component (I_to) and a steady-state outward component (I_∞). I_to was transiently followed by the cessation of inward Ca^2⁢ current (I_Ca), and its current-voltage (I-V) relation was a mirror image of that of I_Ca. Either blockade of I_Ca by Co^2⁢ or replacement of Ca^2⁢ with Sr^2⁢ abolished I_to without change in I_∞. Intracellular EGTA (10 mM) inhibited I_to but not I_∞. suggesting strongly that generation of I_to requires intracellular Ca^2⁢. Apamin (1 nM) abolished selectively I_to, indicating that I_to is Ca^2⁢-dependent K^⁢ current. On the other hand, I_∞ was Ca^2⁢- independent. Both I_to and I_∞ were completely inhibited by internal Cs^⁢ and external TEA. The estimated reversal potential of I_to was close to the theoretical E_K. Taken together, both outward currents were carried by K^⁢ channels. From these results, I_to is likely to be a current responsible for the hyperpolarizing responses seen in hamster eggs at fertilization.

키워드

K^⁢ currents Ca^2⁢ -dependent K^⁢ current Whole-cell current Hamster oocytes