title: Effects of calcium channel blockers on calcium release-activated calcium currents in rat hepatocytes.
abstract: OBJECTIVE
  To study the influences of calcium channel blockers on calcium release-activated calcium currents (ICRAC) in rat hepatocytes.
  
  
  METHODS
  Whole-cell patch-clamp technique was used.
  
  
  RESULTS
  The peak amplitude of ICRAC was -0.41 nA +/- 0.09 nA (n = 15), its reversal potential was about 0 mV. Verapamil (Ver), diltiazem (Dil), and nifedipine (Nif) decreased ICRAC strikingly, without affecting its reversal potential. The inhibitory rate of Ver 5 mumol.L-1 was 40% +/- 12% (n = 3), Ver 50 mumol.L-1 reduced the peak amplitude of ICRAC from -0.49 nA +/- 0.12 nA to -0.20 nA +/- 0.09 nA (P < 0.01 vs control, n = 5). The inhibitory rate was 57% +/- 15%. Dil 50 mumol.L-1 and Nif reduced ICRAC from -0.43 nA +/- 0.10 nA to -0.29 nA +/- 0.07 nA (P < 0.01 vs control, n = 5), from -0.32 nA +/- 0.08 nA to -0.27 nA +/- 0.08 nA (P < 0.01 vs control, n = 5). The inhibitory rate was 31% +/- 11%, 19% +/- 7%, respectively. The amplitude of ICRAC was dependent on extracellular Ca2+ concentration. The peak amplitude of ICRAC was -0.21 nA +/- 0.08 nA (n = 3) in Tyrode's solution with Ca2+ 1.8 mmol.L-1 (P < 0.01 vs the peak amplitude of ICRAC in external solution with Ca2+ 10 mmol.L-1).
  
  
  CONCLUSIONS
  The three calcium antagonists inhibited ICRAC effectively and protected hepatocytes from calcium overload via the inhibition of ICRAC.
authors.affiliation: Department of Pharmacology, China Medical University, Shenyang, China.
authors.forename: G Y
authors.initials: GY
authors.lastname: Cui
authors.forename: J M
authors.initials: JM
authors.lastname: Li
authors.forename: H
authors.initials: H
authors.lastname: Cui
authors.forename: L Y
authors.initials: LY
authors.lastname: Hao
authors.forename: D J
authors.initials: DJ
authors.lastname: Liu
authors.forename: K Y
authors.initials: KY
authors.lastname: Zhang
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects*; D002478:Cells, Cultured; D004110:Diltiazem / Q000494:pharmacology; D005260:Female; D008099:Liver / Q000166:cytology*; D008297:Male; D009543:Nifedipine / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D014700:Verapamil / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D015220:Calcium Channels; D014700:Verapamil; D004110:Diltiazem; D009543:Nifedipine