title: (-)-Epicatechin administration and exercising skeletal muscle vascular control and microvascular oxygenation in healthy rats.
abstract: Consumption of the dietary flavanol (-)-epicatechin (EPI) is associated with enhanced endothelial function and augmented skeletal muscle capillarity and mitochondrial volume density. The potential for EPI to improve peripheral vascular function and muscle oxygenation during exercise is unknown. We tested the hypothesis that EPI administration in healthy rats would improve treadmill exercise performance secondary to elevated skeletal muscle blood flow and vascular conductance [VC, blood flow/mean arterial pressure (MAP)] and improved skeletal muscle microvascular oxygenation. Rats received water (control, n = 12) or 4 mg/kg EPI (n = 12) via oral gavage daily for 24 days. Exercise endurance capacity and peak O(2) uptake (Vo(2) peak) were measured via treadmill runs to exhaustion. MAP (arterial catheter) and blood flow (radiolabeled microspheres) were measured and VC was calculated during submaximal treadmill exercise (25 m/min, 5% grade). Spinotrapezius muscle microvascular O(2) pressure (Po(2mv)) was measured (phosphorescence quenching) during electrically induced twitch (1 Hz) contractions. In conscious rats, EPI administration resulted in lower (↓~5%) resting (P = 0.03) and exercising (P = 0.04) MAP. There were no differences in exercise endurance capacity, Vo(2) peak, total exercising hindlimb blood flow (control, 154 ± 13; and EPI, 159 ± 8 ml·min(-1)·100 g(-1), P = 0.68), or VC (control, 1.13 ± 0.10; and EPI, 1.24 ± 0.08 ml·min(-1)·100 g(-1)·mmHg(-1), P = 0.21) between groups. Following anesthesia, EPI resulted in lower MAP (↓~16%) but did not impact resting Po(2mv) or any kinetics parameters (P > 0.05 for all) during muscle contractions compared with control. EPI administration (4 mg·kg(-1)·day(-1)) improved modestly cardiovascular function (i.e., ↓MAP) with no impact on exercise performance, total exercising skeletal muscle blood flow and VC, or contracting muscle microvascular oxygenation in healthy rats.
authors.affiliation: Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, USA.
authors.forename: Steven W
authors.initials: SW
authors.lastname: Copp
authors.forename: Tadakatsu
authors.initials: T
authors.lastname: Inagaki
authors.forename: Michael J
authors.initials: MJ
authors.lastname: White
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Hirai
authors.forename: Scott K
authors.initials: SK
authors.lastname: Ferguson
authors.forename: Clark T
authors.initials: CT
authors.lastname: Holdsworth
authors.forename: Gabrielle E
authors.initials: GE
authors.lastname: Sims
authors.forename: David C
authors.initials: DC
authors.lastname: Poole
authors.forename: Timothy I
authors.initials: TI
authors.lastname: Musch
mesh_terms: D000284:Administration, Oral; D000818:Animals; D062186:Arterial Pressure / Q000187:drug effects; D002392:Catechin / Q000008:administration & dosage / Q000494:pharmacology*; D017079:Exercise Tolerance / Q000187:drug effects; D006614:Hindlimb; D007700:Kinetics; D008297:Male; D008833:Microcirculation / Q000187:drug effects*; D009119:Muscle Contraction / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000187:drug effects* / Q000378:metabolism; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption / Q000187:drug effects*; D005082:Physical Exertion; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000187:drug effects; D012420:Running; D014664:Vasodilation / Q000187:drug effects
chemical_list: D002392:Catechin; D010100:Oxygen