Effects of dietary omega-3 polyunsaturated Fatty acids on the skeletal-muscle blood-flow response to exercise in rats.
The polyunsaturated fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) affect vascular relaxation and involve factors (e.g., nitric oxide) that contribute to exercise-induced increases in skeletal-muscle blood flow (Q). The authors investigated whether DHA and EPA supplementation augments skeletal-muscle Q and vascular conductance (VC) and attenuates renal and splanchnic Q and VC in exercising rats. Rats were fed a diet of 5% lipids by weight, of which 20% was DHA and 30% EPA (PUFA group, n = 9), or 5% safflower oil (SO group, n = 8) for 6 wk. Heart rate (HR), blood pressure (MAP), and hind-limb, renal, and splanchnic Q were measured at rest and during moderate treadmill running. MAP, HR, and renal and splanchnic Q and VC were similar between the 2 groups at rest and during exercise. In the PUFA group, Q (158 ± 27 vs. 128 ± 28 ml × min⁻¹ × 100 g⁻¹) and VC (1.16 ± 0.21 vs. 0.92 ± 0.23 ml × min⁻¹ × 100 g⁻¹ × mm Hg⁻¹) were greater in the exercising hind-limb muscle. Q and VC were also higher in 8 of 28 and 11 of 28 muscles and muscle parts, respectively. These increases were positively correlated to the percent sum of Types I and IIa fibers. Results suggest that DHA+EPA (a) enhances Q and VC in active skeletal muscle (especially Type I and IIa fibers) and that the increase in Q is due to an increase in cardiac output secondary to increases in VC and (b) has no apparent influence on vasoconstriction in renal and splanchnic tissue.
Dept. of Internal Medicine, Div. of Cardiovascular Medicine, University of California, Davis, Davis, CA, USA.
Charles L
CL
Stebbins
Lauren E
LE
Hammel
Benjamin J
BJ
Marshal
Espen E
EE
Spangenberg
Timothy I
TI
Musch
D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D004281:Docosahexaenoic Acids / Q000494:pharmacology; D015118:Eicosapentaenoic Acid / Q000494:pharmacology; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000187:drug effects / Q000502:physiology; D010805:Physical Conditioning, Animal / Q000379:methods / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow; D012146:Rest; D012450:Safflower Oil / Q000008:administration & dosage; D014655:Vascular Resistance / Q000187:drug effects*
D015525:Fatty Acids, Omega-3; D004281:Docosahexaenoic Acids; D012450:Safflower Oil; D015118:Eicosapentaenoic Acid