Dietary fish oil prevents reperfusion ins(1,4,5)p3 release in rat heart : a possible antiarrhythmic mechanism. Anderson, Karen E., Xiao-Jun Du, Andrew J. Sinclair, Elizabeth A. Woodcock, and Anthony M. Dart. Cellular Biochemistry Laboratory, Baker Medical Research Institute, Experimental Cardiology Laboratory, Alfred Baker Medical Unit, Prahran, 3181, Australia, Department of Food Science, Royal Melbourne Institute of Technology, Melbourne, 3001, Australia
APStracts 3:0172H, 1996.
Dietary enrichment with fish oil derived n-3 polyunsaturated fatty acids has been shown to suppress the arrhythmias that occur during post-ischemic reperfusion. We have recently implicated a rapid release of inositol(1,4,5)trisphosphate (Ins(1,4,5)P3) during post -ischemic reperfusion in the generation of these arrhythmias. The effects of dietary supplementation with fish oil on both cardiac Ins(1,4,5)P3 and arrhythmogenic responses to reperfusion were therefore investigated in perfused rat hearts. Comparisons were made with control, and n-6 polyunsaturated, or saturated fat supplemented diets. In control hearts, reperfusion increased Ins(1,4,5)P3 levels (from 9 +/- 2 at 20 min ischemia to 26 +/- 3 cpm/mg protein with 2 min reperfusion) and produced a high incidence of ventricular tachycardia (92% VT) and ventricular fibrillation (85% VF). Dietary fish oil supplementation which increased composition of n-3 fatty acids in myocardial membrane phospholipids, prevented the reperfusion-induced rise in Ins(1,4,5)P3 (11 +/- 1 at 20 min ischemia, and 12 +/- 2 cpm/mg protein following 2 min reperfusion), and significantly suppressed reperfusion arrhythmias (38% VT, 13% VF, p&LT0.01 versus control group). Thus, the inhibition of reperfusion-induced rises in Ins(1,4,5)P3 by n-3 polyunsaturated fatty acids following dietary fish oil supplementation provides a possible mechanism for the inhibitory effect of n-3 fatty acids on reperfusion-induced arrhythmias. 

Received 15 September 1995; accepted in final form 16 April 1996.
APS Manuscript Number H872-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 1 May 96