Gamma-linolenic acid provides additional protection against ventricular fibrillation in aged rats fed linoleic acid rich diets.
Ligation of the coronary artery in rats produces severe ventricular fibrillation (VF) and malignant cardiac arrhythmia. Mortality increases with the age of the animal. Diets rich in saturated fatty acids (SF) but low in linoleic acid (LA) increase, but diets high in LA and low in SF decrease the severity of VF and mortality in older animals. The effects of an LA enriched diet can be blocked by inhibition of cyclooxygenase suggesting that conversion of LA to eicosanoids is central to the development of VF. Conversion of LA to gamma-linolenic acid (GLA) via delta-6 desaturase is the first step in the process. The activity of delta-6 desaturase declines with age. Thus inclusion of GLA in the diet of older animals may provide an additional benefit over LA alone. Dietary supplements of evening primrose oil (EPO) to one year old rats reduced ischaemic VF more than a supplement of sunflower seed oil (SSO) without GLA. Substitution of borage oil (more GLA than EPO but less LA than either EPO or SSO) was without additional benefit.
Charnock
J S
JS
Charnock & Associates, Carrickalinga, South Australia, Australia.
D000375:Aging; D000818:Animals; D003331:Coronary Vessels / Q000601:surgery; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004041:Dietary Fats / Q000008:administration & dosage; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage*; D044943:Fatty Acid Desaturases / Q000378:metabolism; D005228:Fatty Acids, Essential / Q000008:administration & dosage; D008026:Ligation; D019787:Linoleic Acid / Q000008:administration & dosage*; D008041:Linoleic Acids; D050602:Linoleoyl-CoA Desaturase; D008297:Male; D031665:Oenothera biennis; D019301:Oleic Acid / Q000008:administration & dosage; D010938:Plant Oils; D051381:Rats; D017208:Rats, Wistar; D014693:Ventricular Fibrillation / Q000209:etiology / Q000517:prevention & control*; D014810:Vitamin E / Q000008:administration & dosage; D015430:Weight Gain; D017962:alpha-Linolenic Acid / Q000008:administration & dosage; D017965:gamma-Linolenic Acid / Q000378:metabolism / Q000627:therapeutic use*
D016861:Cyclooxygenase Inhibitors; D004041:Dietary Fats; D004042:Dietary Fats, Unsaturated; D005228:Fatty Acids, Essential; D008041:Linoleic Acids; D010938:Plant Oils; D017962:alpha-Linolenic Acid; D014810:Vitamin E; D019301:Oleic Acid; C028498:evening primrose oil; D017965:gamma-Linolenic Acid; D019787:Linoleic Acid; D044943:Fatty Acid Desaturases; D050602:Linoleoyl-CoA Desaturase