title: [Effects of amiodarone on funny current I(f) channel gene expression in neonatal rat ventricular myocytes].
abstract: OBJECTIVE
  To analysis the effect of amiodarone on funny current (I(f)) and hyperpolarization-activated cation channel (HCN) gene expressions of the neonatal rat ventricular myocytes.
  
  
  METHODS
  Ventricular myocytes of 1 - 3 days-old rats were isolated and cultured. The cardiomyocytes were treated by amiodarone (0.01, 0.1, 1, 10, 100 micromol/L) for 3 hours or amiodaron (10 micromol/L) for 0, 0.5, 1, 3, 6 hours. The I(f) and HCN 1 - 4 gene expressions were measured through the whole-cell configuration of the patch-clamp technique and real-time quantitative polymerase chain reaction (real-time PCR) using SYBR Green PCR kit.
  
  
  RESULTS
  (1) HCN1, HCN2, HCN3 and HCN4 represented (0.23 +/- 0.01)%, (83.58 +/- 0.04)%, (0.79 +/- 0.01)% and (15.44 +/- 0.01)% of total HCN mRNA, respectively. (2) Amiodaron resulted in a dose-dependent I(f) [(3.1 +/- 0.9)%, (9.7 +/- 2.4)%, (36.7 +/- 5.8)%, (80.3 +/- 1.8)% and (85.9 +/- 3.1)%, respectively at -145 mV, IC(50) (1.32 +/- 0.28) micromol/L], HCN2 [(2.1 +/- 0.8)%, (8.9 +/- 3.6)%, (30.1 +/- 4.2)%, (78.3 +/- 3.6)% and (81.1 +/- 1.9)%, respectively] and HCN4 decrease [(0.5 +/- 0.2)%, (2.1 +/- 2.6)%, (8.8 +/- 3.2)%, (60.1 +/- 4.6)% and (59.6 +/- 6.5)%, respectively]. (3) Amiodaron (10 micromol/L) also induced a time-dependent I(f) [(1.1 +/- 0.1)%, (12.6 +/- 2.3)%, (80.6 +/- 2.2)% and (80.1 +/- 2.1)%, respectively], HCN2 [(1.0 +/- 0.1)%, (9.8 +/- 3.9)%, (82.9 +/- 4.6)% and (83.9 +/- 1.7)%, respectively] and HCN4 decrease [(0.1 +/- 0.1)%, (1.9 +/- 1.1)%, (59.4 +/- 7.8)% and (60.9 +/- 3.1)%, respectively]. However, HCN1 and HCN3 expressions were not affected by amiodaron treatment.
  
  
  CONCLUSIONS
  Current density of I(f) and the expression of HCN2 and HCN4 were decreased by amiodaron which might be the possible antiarrhythmic working mechanisms of amiodaron.
authors: Department of the Cardiology, The First Affiliated Hospital of Soochow University, Suzhou, China.
authors: Hong-Xia
authors: HX
authors: Li
authors: Xiang-Jun
authors: XJ
authors: Yang
authors: Lian-Hua
authors: LH
authors: Han
authors: Ya-Feng
authors: YF
authors: Zhou
authors: Xin
authors: X
authors: Zhao
authors: Bin
authors: B
authors: Jiang
authors: Ning-Zheng
authors: NZ
authors: Dong
authors: Jian-Ping
authors: JP
authors: Song
authors: Zhi-Hua
authors: ZH
authors: Liu
authors: Wen-Ping
authors: WP
authors: Jiang
mesh_terms: D000638:Amiodarone / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D054815:Cyclic Nucleotide-Gated Cation Channels / Q000235:genetics / Q000378:metabolism*; D005260:Female; D015870:Gene Expression; D006352:Heart Ventricles / Q000378:metabolism; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D008297:Male; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D054815:Cyclic Nucleotide-Gated Cation Channels; C578667:Hcn1 protein, rat; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D015221:Potassium Channels; D000638:Amiodarone