Effect of palmitic acid and fatty acid binding protein on ventricular fibrillation threshold in the perfused rat heart.
The effects of increased free fatty acid (FFA) levels on ventricular arrhythmias remain controversial. Using ventricular fibrillation threshold (VFT), we examined the relationship between FFA levels and ventricular arrhythmias. Isolated rat hearts were perfused with palmitate bound to either albumin or fatty acid binding protein (FABP) by Langendorf's method. The VFT was determined by electrical stimulation. Perfusion with 0.12 mM albumin alone, 0.12 mM palmitate bound to 0.12 mM albumin, and 0.36 mM palmitate bound to 0.12 mM albumin did not lower the VFT significantly. However, 0.60 mM palmitate bound to 0.12 mM albumin lowered VFT from 2.19 +/- 0.20 mA to 1.56 +/- 0.13 mA. The perfusion of 0.36 mM palmitate bound to 0.12 mM FABP lowered the VFT from 2.05 +/- to 0.19 mA to 1.47 +/- 0.23 mA, but 0.12 mM FABP alone did not affect the VFT. Perfusion with 0.36 mM palmitate bound to 0.12 mM FABP caused the VFT to fall more than perfusion with 0.36 mM palmitate bound to 0.12 mM albumin. Then the effects of verapamil perfusion or a low concentration of perfusate Ca2+ on VFT were examined. VFT was determined by electrical stimulation. Palmitate (0.6 mM) bound to 0.12 mM albumin lowered VFT. Verapamil 10(-7) M perfusion and a low concentration of Ca2+ (Ca2+ 1.67 mM) suppressed the FFA-induced fall of VFT. These results suggested that the arrhythmogenic action of FFA was related to Ca2+ overload in myocardial cells.
Makiguchi
M
M
Department of Cardiovascular Medicine, Hokkaido University School of Medicine, Japan.
Kawaguchi
H
H
Tamura
M
M
Yasuda
H
H
D000418:Albumins / Q000008:administration & dosage; D000818:Animals; D002352:Carrier Proteins / Q000494:pharmacology*; D003326:Coronary Circulation / Q000187:drug effects; D004558:Electric Stimulation; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids / Q000378:metabolism*; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains; D014693:Ventricular Fibrillation / Q000209:etiology*; D016277:Ventricular Function, Left / Q000187:drug effects
D000418:Albumins; D002352:Carrier Proteins; C490174:Fabp7 protein, rat; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D010169:Palmitic Acids; D019308:Palmitic Acid