Long-term effect of dietary {alpha}-linolenic acid or decosahexaenoic acid on incorporation of decosahexaenoic acid in membranes and its influence on rat heart in vivo.
The present study was designed to evaluate whether long-term intake of dietary alpha-linolenic acid (ALA), supplied as whole grain-extruded linseed, can increase endogenous production of n-3 long-chain polyunsaturated fatty acids (FAs) in healthy adult rats and influence the heart rate (HR) and adrenergic response in the same way as docosahexaenoic acid (DHA)-rich diets. DHA enrichment was evaluated using FA analysis of tissue phospholipids after 8, 16, 24, and 32 wk of feeding in male Wistar rats randomly assigned to three dietary groups (n = 8 in each group): a reference fat diet (RFD), an ALA-rich (ALA) diet, and a DHA-rich (DHA) diet. At 1 wk before the animals were killed, under anesthesia, HR was measured from ECG recordings during an adrenergic stimulation challenge (n = 8). There was a significant increase of DHA in the cardiac membrane in the ALA group compared with the RFD group. DHA content in the cardiac membrane was approximately 10% in the ALA group vs. 20% in the DHA group and 4% in the RFD group. The cardiac FA profile was established after 2 mo and remained essentially unchanged thereafter. Regardless of the diet, DHA in the heart decreased with age. Nevertheless, DHA content in the heart remained at >15% in the DHA group and remained greater in older rats fed the ALA diet than in younger RFD-fed rats. Basal HR decreased in the ALA group (395 +/- 24.9 beats/min) to a level between that of the DHA and RFD groups (375 +/- 26.4 and 407 +/- 36.7 beats/min, respectively). Both n-3 dietary intakes contribute to enhancement of the chronotropic response to adrenergic agonist stimulation. Regulation of HR by neurohumoral mediators may be controlled by lower content of DHA, e.g., by a dietary supply of extruded linseed (ALA).
Ayalew-Pervanchon
Adey
A
Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1154, Lipides Membranaires et Régulation Fonctionnelle du Coeur et des Vaisseaux, Châtenay-Malabry, France.
Rousseau
Delphine
D
Moreau
Daniel
D
Assayag
Patrick
P
Weill
Pierre
P
Grynberg
Alain
A
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects* / Q000378:metabolism; D004041:Dietary Fats / Q000097:blood / Q000378:metabolism / Q000494:pharmacology*; D004281:Docosahexaenoic Acids / Q000097:blood / Q000378:metabolism / Q000494:pharmacology*; D004562:Electrocardiography; D006321:Heart / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects*; D007545:Isoproterenol / Q000494:pharmacology*; D050356:Lipid Metabolism / Q000187:drug effects; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D017962:alpha-Linolenic Acid / Q000097:blood / Q000378:metabolism / Q000494:pharmacology*
D000318:Adrenergic beta-Agonists; D004041:Dietary Fats; D017962:alpha-Linolenic Acid; D004281:Docosahexaenoic Acids; D007545:Isoproterenol