Dynamics of n-3 and n-6 fatty acids in phospholipids of heart muscle.

The purpose of this paper is to describe the dynamics of n-3 and n-6 polyunsaturated fatty acids in major phospholipids of heart muscle. The profile of n-3 and n-6 fatty acids was examined in rats in relation to various risk factors of coronary heart disease such as stress (catecholamines), ageing and dietary fat. The level of n-3 and n-6 fatty acids in cardiac phospholipids was also examined in relation to coronary heart disease and sudden cardiac death in man. Severe stress caused great changes in the fatty acid profile of phospholipids. Corresponding changes were observed during adaptation to neonatal stress. Rats fed diets containing cod liver oil, butter or corn oil showed different fatty acid composition of individual phospholipids in sarcolemma. Repeated epinephrine administration induced similar changes in the three dietary groups despite large differences in initial levels of individual n-3 and n-6 fatty acids. Fatal ventricular fibrillation in rats and sudden cardiac death in man were accompanied by a high ratio of 20:4 n-6/22:6 n-3. The balance between n-6 and n-3 fatty acids in cellular phospholipids seem to play an important role in sudden cardiac death.