title: Dual effects of tetrandrine on calcium-activated potassium channels in pulmonary artery smooth muscle cells.
abstract: OBJECTIVE
  To study the effects of tetrandrine (Tet) on calcium-activated potassium channels.
  
  
  METHODS
  Inside-out configuration of patch-clamp single channel recording techniques.
  
  
  RESULTS
  Tet 7.5 and 15 mumol.L-1 increased the open probability from control value 0.251 +/- 0.012 to 0.340 +/- 0.013 and 0.415 +/- 0.011, respectively (P < 0.01), decreased the close time from (61 +/- 15) ms to (33 +/- 10) and (28 +/- 11) ms, respectively (P < 0.01). But Tet 30 mumol.L-1 decreased the open probability and open time to (0.114 +/- 0.008) and (1.47 +/- 0.09) ms, respectively [P < 0.01 vs control (0.251 +/- 0.012) and (20 +/- 8) ms].
  
  
  CONCLUSIONS
  Tet has concentration-dependent dual effects on KCa channels in isolated rat pulmonary smooth muscle cells.
authors.affiliation: Department of Physiology, Third Military Medical University, Chongqing, China.
authors.forename: Z F
authors.initials: ZF
authors.lastname: Wang
authors.forename: L
authors.initials: L
authors.lastname: Kai
authors.forename: X R
authors.initials: XR
authors.lastname: Xiao
mesh_terms: D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D044182:Benzylisoquinolines; D002118:Calcium / Q000494:pharmacology; D002469:Cell Separation; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000187:drug effects; D011651:Pulmonary Artery / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000470:Alkaloids; D000889:Anti-Arrhythmia Agents; D044182:Benzylisoquinolines; D015221:Potassium Channels; C009438:tetrandrine; D002118:Calcium