Influence of dietary linoleic acid on cardiac function and prostaglandin release and on the effects of isoprenaline in the isolated rat heart.
We studied the effects of dietary linoleate on cardiac function and on the effectiveness of isoprenaline in isolated rat heart preparations. Male Wistar rats were fed either a diet rich in linoleic acid (LA) (25% of digestible energy as sunflower oil, 5% lard) or an LA-deficient diet (30% hydrogenated palm kernel oil). Control rats received a standard lab chow. Under certain experimental conditions the LA-rich diet resulted in increased contractile force, coronary flow rate, and prostaglandin (PG) release (PG-like substances and PGI2) and in a reduction in heart rate. These effects were modified by the duration of the feeding period and/or the age of the animals. In isolated perfused hearts of rats fed on a diet rich in LA for a 10-week period the inotropic effects of isoprenaline were diminished, whereas the isoprenaline-induced increase in coronary flow rate was augmented. The PG-releasing effect of isoprenaline was antagonized by the LA-rich diet. Preliminary in vivo investigations support these in vitro results. The mechanisms by which dietary LA influences cardiac function and the effectiveness of isoprenaline remain unclear.
D000821:Animal Feed; D000818:Animals; D001783:Blood Flow Velocity; D001794:Blood Pressure / Q000187:drug effects; D004041:Dietary Fats / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects / Q000502:physiology*; D006334:Heart Function Tests; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology*; D008041:Linoleic Acids / Q000494:pharmacology*; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism*; D010477:Perfusion; D011453:Prostaglandins / Q000096:biosynthesis*; D051381:Rats; D011919:Rats, Inbred Strains
D004041:Dietary Fats; D008041:Linoleic Acids; D011453:Prostaglandins; D007545:Isoproterenol