Van Renterghem C, Lazdunski M
Institut de Pharmacologie Moléculaire et Cellulaire, C.N.R.S., Valbonne, France.
Pflugers Arch. 1992 Apr;420(5-6):417-23. doi: 10.1007/BF00374614.
A small conductance K+ channel was identified in smooth muscle cells of the rat aortic cell line A7r5 and also in rat aortic smooth muscle cells in primary culture, using conventional single-channel recording techniques. The single-channel conductance shows no rectification, either in the range -70 to +40 mV under asymmetrical conditions (9.1 pS), or in the range -100 to +50 mV in symmetrical 150 mM K+ (37 pS). Channel activity is reversibly inhibited by extracellular application of charybdotoxin, with a concentration of 8 nM producing half-maximal inhibition. It is unaffected by apamin or scyllatoxin. Channel activity depends on the presence of free Ca2+ on the cytosolic face of the membrane, with an activation zone between 0.1 and 1 microM. This small-conductance, charybdotoxin-sensitive, Ca(2+)-regulated K+ channel is activated by vasoconstrictors such as vasopressin and endothelin.
利用传统的单通道记录技术，在大鼠主动脉细胞系A7r5的平滑肌细胞以及原代培养的大鼠主动脉平滑肌细胞中鉴定出一种小电导钾通道。单通道电导在非对称条件下（-70至+40 mV范围，9.1 pS）或对称的150 mM K+中（-100至+50 mV范围，37 pS）均无整流现象。细胞外施加浓度为8 nM的蝎毒素可使通道活性受到可逆性抑制，半数最大抑制浓度为8 nM。该通道不受蜂毒明肽或刺尾鱼毒素影响。通道活性取决于膜胞质面游离Ca2+的存在，激活区在0.1至1 microM之间。这种小电导、对蝎毒素敏感、Ca(2+)调节的钾通道可被血管加压素和内皮素等血管收缩剂激活。
