title: The effects of dietary fish oil on exercising skeletal muscle vascular and metabolic control in chronic heart failure rats.
abstract: Impaired vasomotor control in chronic heart failure (CHF) is due partly to decrements in nitric oxide synthase (NOS) mediated vasodilation. Exercising muscle blood flow (BF) is augmented with polyunsaturated fatty acid (PUFA) supplementation via fish oil (FO) in healthy rats. We hypothesized that FO would augment exercising muscle BF in CHF rats via increased NO-bioavailability. Myocardial infarction (coronary artery ligation) induced CHF in Sprague-Dawley rats which were subsequently randomized to dietary FO (20% docosahexaenoic acid, 30% eicosapentaenoic acid, n = 15) or safflower oil (SO, 5%, n = 10) for 6-8 weeks. Mean arterial pressure (MAP), blood [lactate], and hindlimb muscles BF (radiolabeled microspheres) were determined at rest, during treadmill exercise (20 m·min(-1), 5% incline) and exercise + N(G)-nitro-l-arginine-methyl-ester (l-NAME) (a nonspecific NOS inhibitor). FO did not change left ventricular end-diastolic pressure (SO: 14 ± 2; FO: 11 ± 1 mm Hg, p > 0.05). During exercise, MAP (SO: 128 ± 3; FO: 132 ± 3 mm Hg) and blood [lactate] (SO: 3.8 ± 0.4; FO: 4.6 ± 0.5 mmol·L(-1)) were not different (p > 0.05). Exercising hindlimb muscle BF was lower in FO than SO (SO: 120 ± 11; FO: 93 ± 4 mL·min(-1)·100 g(-1), p < 0.05) but was not differentially affected by l-NAME. Specifically, 17 of 28 individual muscle BF's were lower (p < 0.05) in FO demonstrating that PUFA supplementation with FO in CHF rats does not augment muscle BF during exercise but may lower metabolic cost.
authors.affiliation: a Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506-5802, USA.
authors.forename: Clark T
authors.initials: CT
authors.lastname: Holdsworth
authors.forename: Steven W
authors.initials: SW
authors.lastname: Copp
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Hirai
authors.forename: Scott K
authors.initials: SK
authors.lastname: Ferguson
authors.forename: Gabrielle E
authors.initials: GE
authors.lastname: Sims
authors.forename: Karen S
authors.initials: KS
authors.lastname: Hageman
authors.forename: Charles L
authors.initials: CL
authors.lastname: Stebbins
authors.forename: David C
authors.initials: DC
authors.lastname: Poole
authors.forename: Timothy I
authors.initials: TI
authors.lastname: Musch
mesh_terms: D000818:Animals; D002908:Chronic Disease; D004042:Dietary Fats, Unsaturated / Q000494:pharmacology*; D005395:Fish Oils / Q000494:pharmacology*; D006333:Heart Failure / Q000378:metabolism* / Q000503:physiopathology*; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000187:drug effects* / Q000503:physiopathology; D009569:Nitric Oxide / Q000502:physiology; D010805:Physical Conditioning, Animal / Q000502:physiology*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000187:drug effects*; D014664:Vasodilation
chemical_list: D004042:Dietary Fats, Unsaturated; D005395:Fish Oils; D009569:Nitric Oxide