Induction of Ca2+ -Activated K+ Channel Expression during Systemic Hypertension: Protection against Pathological Vasoconstriction
During the past 15 years, patch-clamp studies have characterized a diverse population of K+ channel types in vascular smooth muscle cells. Prominent among these is the high-conductance, Ca2+ -activated K+ channel (BKCa channel), which appears to be ubiquitously expressed in arterial smooth muscle membranes. The BKCa channel in some vascular beds may act together with other K+ channel types to set the level of resting membrane potential in the arterial smooth muscle cells. During vascular excitation, the further activation of BKCa channels may provide a powerful pathway to hyperpolarize the arterial smooth muscle cells, thereby limiting voltage-gated Ca2+ influx and buffering vasoconstriction in small arteries and resistance vessels. Thus, under physiological conditions, the BKCa channel acts as a homeostatic mechanism to counteract arterial constriction and maintain blood flow to critical organs and tissues.
KeywordsVascular Smooth Muscle Cell Blood Pressure Level Rest Membrane Potential Aortic Smooth Muscle Cell Arterial Smooth Muscle Cell
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