title: Amyloid peptide regulates calcium homoeostasis and arrhythmogenesis in pulmonary vein cardiomyocytes.
abstract: BACKGROUND
  Amyloid peptides modulate cardiac calcium homoeostasis and play an important role in the pathophysiology of atrial fibrillation. Pulmonary veins (PVs) are critical in the genesis of atrial fibrillation and contain abundant amyloid peptides. Therefore, the purpose of this study is to investigate whether amyloid peptides may change the PV electrical activity through regulating calcium homoeostasis.
  
  
  RESULTS
  The channel and calcium-handling protein expressions, intracellular calcium and ionic currents were studied in isolated rabbit PV cardiomyocytes in the presence and absence (control) of beta-amyloid (Aβ(25-35) ) for 4-6 h, using Western blot analysis, indo-1 fluorimetric ratio and whole-cell patch clamp techniques. Aβ(25-35) decreased the expressions of Ca(V) 1.2, total or Ser16-phosphorylated phospholamban (p-PLB), p-PLB/PLB ratio, sodium/calcium exchanger, but did not change ryanodine receptor, sarcoplasmic reticulum (SR) ATPase and K(+) channel proteins (Kir2.1, Kir2.3, Kv1.4, Kv1.5 and Kv4.2). Aβ(25-35) -treated cardiomyocytes had smaller calcium transient, SR calcium store, L-type calcium current and sodium/calcium exchanger current than control cardiomyocytes. Moreover, Aβ(25-35) -treated cardiomyocytes (n = 20) had shorter 90% of the action potential duration (82 ± 3 vs. 93 ± 5 ms, P < 0·05) than control cardiomyocytes (n = 16).
  
  
  CONCLUSIONS
  Aβ(25-35) has direct electrophysiological effects on PV cardiomyocytes.
authors: Division of Cardiology, National Yang-Ming University Hospital, I-Lan, Taiwan.
authors: Hsuan-Ming
authors: HM
authors: Tsao
authors: Punate
authors: P
authors: Weerateerangkul
authors: Yao-Chang
authors: YC
authors: Chen
authors: Yu-Hsun
authors: YH
authors: Kao
authors: Yung-Kuo
authors: YK
authors: Lin
authors: Jen-Hung
authors: JH
authors: Huang
authors: Shih-Ann
authors: SA
authors: Chen
authors: Yi-Jen
authors: YJ
authors: Chen
mesh_terms: D000200:Action Potentials / Q000502:physiology; D016229:Amyloid beta-Peptides / Q000494:pharmacology*; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000378:metabolism*; D001281:Atrial Fibrillation / Q000378:metabolism*; D015153:Blotting, Western / Q000379:methods; D002118:Calcium / Q000378:metabolism*; D005470:Fluorometry / Q000379:methods; D006706:Homeostasis; D008297:Male; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism; D018408:Patch-Clamp Techniques / Q000379:methods; D011667:Pulmonary Veins / Q000166:cytology*; D011817:Rabbits; D019831:Sodium-Calcium Exchanger / Q000378:metabolism; D013223:Statistics as Topic
chemical_list: D016229:Amyloid beta-Peptides; D019831:Sodium-Calcium Exchanger; D002118:Calcium