Physiological roles and properties of potassium channels in arterial smooth muscle.
This review examines the properties and roles of the four types of K+ channels that have been identified in the cell membrane of arterial smooth muscle cells. 1) Voltage-dependent K+ (KV) channels increase their activity with membrane depolarization and are important regulators of smooth muscle membrane potential in response to depolarizing stimuli. 2) Ca(2+)-activated K+ (KCa) channels respond to changes in intracellular Ca2+ to regulate membrane potential and play an important role in the control of myogenic tone in small arteries. 3) Inward rectifier K+ (KIR) channels regulate membrane potential in smooth muscle cells from several types of resistance arteries and may be responsible for external K(+)-induced dilations. 4) ATP-sensitive K+ (KATP) channels respond to changes in cellular metabolism and are targets of a variety of vasodilating stimuli. The main conclusions of this review are: 1) regulation of arterial smooth muscle membrane potential through activation or inhibition of K+ channel activity provides an important mechanism to dilate or constrict arteries; 2) KV, KCa, KIR, and KATP channels serve unique functions in the regulation of arterial smooth muscle membrane potential; and 3) K+ channels integrate a variety of vasoactive signals to dilate or constrict arteries through regulation of the membrane potential in arterial smooth muscle.
Nelson
M T
MT
Department of Pharmacology, University of Vermont, Colchester 05446, USA.
Quayle
J M
JM
D000818:Animals; D001158:Arteries / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D008564:Membrane Potentials; D009131:Muscle, Smooth, Vascular / Q000378:metabolism* / Q000502:physiology; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
D015221:Potassium Channels; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents