title: [Properties of large-conductance calcium-activated potassium channel in rat mesenteric arteriole smooth muscle cells].
abstract: OBJECTIVE
  To investigate the electrophysiological properties of large-conductance calcium-activated potassium channel (BKCa) in mesenteric arteriole smooth muscle cells of rat.
  
  
  METHODS
  Mesenteric arteriolar smooth muscle cells from rats were isolated and inside-out patch clamp technique was used to study BKCa.
  
  
  RESULTS
  The single channel conductance of BKCa recorded was 221+/-6 pS and the reversal potential was -0.12 mV in the presence of high potassium in the bathing and pipette solutions. The open probability (NPo) of the channel was both voltage- and intracellular calcium dependent, whereas the amplitude of the channel was not calcium-dependent. Prolonged closed state could be observed at intracellular calcium concentrations of 1 micromol/L or above, known as calcium-dependent inactivation.
  
  
  CONCLUSIONS
  BKCa in rat mesenteric arterial smooth muscle cells has the properties of large conductance, high potassium selectivity, steep voltage dependence and high calcium sensitivity. The high sensitivity to calcium of BKCa may be related to the compensatory regulation of the smooth muscles in pathophysiological conditions.
authors.affiliation: Department of Pathophysiology, First Military Medical University, Guangzhou 510515, China. laura@fimmu.com
authors.forename: Gui-ling
authors.initials: GL
authors.lastname: Zhao
authors.forename: Bing-xing
authors.initials: BX
authors.lastname: Pan
authors.forename: Xu-liang
authors.initials: XL
authors.lastname: Huang
authors.forename: Ke-sen
authors.initials: KS
authors.lastname: Zhao
mesh_terms: D000818:Animals; D005260:Female; D008297:Male; D008564:Membrane Potentials; D008638:Mesenteric Arteries / Q000166:cytology / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D024681:Potassium Channels, Calcium-Activated / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D024681:Potassium Channels, Calcium-Activated