title: Effects of N-methyl berbamine on delayed outward potassium current in isolated rat hepatocytes.
abstract: OBJECTIVE
  To study the effects of N-methyl berbamine (NMB) on the delayed outward potassium currents (Ik) in isolated rat hepatocytes.
  
  
  METHODS
  With patch-clamp techniques and whole-cell recording method, holding potential -50 mV, command potential +30 to +140 mV, duration 900 ms.
  
  
  RESULTS
  NMB reduced Ik in a concentration-dependent manner. When the concentrations of NMB were 20, 50, 400 nmol.L-1 and 50 mumol.L-1, the amplitude values of Ik were decreased to 3.6 +/- 0.4 (P > 0.05), 2.1 +/- 1.6 (P > 0.05), 3.7 +/- 1.6 (P < 0.05), 2.3 +/- 1.3 nA (P < 0.01) from 4.4 +/- 1.0 (n = 4), 2.5 +/- 1.8 (n = 4), 5.8 +/- 2.1 (n = 5), 4.6 +/- 1.3 (n = 6) nA of control, respectively. The inhibitory rates were 10%, 15%, 37%, and 51%, respectively.
  
  
  CONCLUSIONS
  NMB was a K+ channel inhibitor.
authors.affiliation: Department of Pharmacology, China Medical University, Shenyang, China.
authors.forename: J M
authors.initials: JM
authors.lastname: Li
authors.forename: G Y
authors.initials: GY
authors.lastname: Cui
authors.forename: D J
authors.initials: DJ
authors.lastname: Liu
authors.forename: H
authors.initials: H
authors.lastname: Cui
authors.forename: T H
authors.initials: TH
authors.lastname: Chang
authors.forename: Y P
authors.initials: YP
authors.lastname: Wang
authors.forename: K Y
authors.initials: KY
authors.lastname: Zhang
mesh_terms: D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D044182:Benzylisoquinolines; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D007546:Isoquinolines / Q000494:pharmacology*; D008099:Liver / Q000166:cytology*; D008297:Male; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000470:Alkaloids; D044182:Benzylisoquinolines; D007546:Isoquinolines; C120236:N-methylberbamine; D026902:Potassium Channel Blockers; D015221:Potassium Channels