钙激活钾通道(KCa)是血管平滑肌上最主要的外向电流通道,它在动作电位的复极和节律性漫波活动中起着重要作用。激活KCa可致超极化而舒张血管,阻断KCa可致去极化而收缩血管。许多药物、神经递质、激素或体内活性物质通过对KCa的激活或阻断,调节着血管张力。KCa开放剂往往通过提 Calcium-activated potassium channel (KCa) is the most important outward current channel in vascular smooth muscle. It plays an important role in repolarization and rhythmic circadian action of action potentials. Activation of KCa can cause hyperpolarization and vasodilatation, blocking KCa can cause depolarization and contraction of blood vessels. Many drugs, neurotransmitters, hormones or in vivo active agents regulate vascular tone by activating or blocking KCa. KCa openers are often passed