Local hindlimb antioxidant infusion does not affect muscle glucose uptake during in situ contractions in rat

• Published in: Journal of applied physiology (1985) Vol. 108; no. 5; pp. 1275 - 1283
• Main Authors: MERRY, T. L, DYWER, R. M, BRADLEY, E. A, RATTIGAN, S, MCCONELL, G. K
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Physiological Society 01.05.2010
• Subjects: Acetylcysteine - administration & dosage; Acetylcysteine - metabolism; Amino acids; AMP-Activated Protein Kinases - metabolism; Animals; Antioxidants; Antioxidants - administration & dosage; Antioxidants - metabolism; Biological and medical sciences; Biological Transport; Blood Pressure; Cysteine - blood; Cystine - blood; Electric Stimulation; Fundamental and applied biological sciences. Psychology; Glucose; Glucose - metabolism; Glutathione - metabolism; Heart Rate; Hindlimb; Infusions, Intra-Arterial; Kinases; Male; Muscle Contraction; Muscle Fatigue; Muscle Strength; Muscle, Skeletal - blood supply; Muscle, Skeletal - drug effects; Muscle, Skeletal - innervation; Muscle, Skeletal - metabolism; Musculoskeletal system; p38 Mitogen-Activated Protein Kinases - metabolism; Phosphorylation; Physiology; Proteins; Rats; Rats, Wistar; Reactive Oxygen Species - metabolism; Regional Blood Flow; Rodents; Time Factors; Tyrosine - metabolism; Vascular Resistance; Physical exercise; Reactive oxygen species; Hindlimb; AMP; Rat; Enzyme; Transferases; In situ; Non-specific serine/threonine protein kinase; Rodentia; exercise; Glucose; Antioxidant; Striated muscle; Metabolism; AMP-activated protein kinase; Muscle contraction; Uptake; Vertebrata; Mammalia; S-glutathionylation
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.01335.2009

There is evidence that reactive oxygen species (ROS) contribute to the regulation of skeletal muscle glucose uptake during highly fatiguing ex vivo contraction conditions via AMP-activated protein kinase (AMPK). In this study we investigated the role of ROS in the regulation of glucose uptake and AMPK signaling during low-moderate intensity in situ hindlimb muscle contractions in rats, which is a more physiological protocol and preparation. Male hooded Wistar rats were anesthetized, and then N-acetylcysteine (NAC) was infused into the epigastric artery (125 mg.kg(-1).h(-1)) of one hindlimb (contracted leg) for 15 min before this leg was electrically stimulated (0.1-ms impulse at 2 Hz and 35 V) to contract at a low-moderate intensity for 15 min. The contralateral leg did not receive stimulation or local NAC infusion (rest leg). NAC infusion increased (P<0.05) plasma cysteine and cystine (by approximately 360- and 1.4-fold, respectively) and muscle cysteine (by 1.5-fold, P=0.001). Although contraction did not significantly alter muscle tyrosine nitration, reduced (GSH) or oxidized glutathione (GSSG) content, S-glutathionylation of protein bands at approximately 250 and 150 kDa was increased (P<0.05) approximately 1.7-fold by contraction, and this increase was prevented by NAC. Contraction increased (P<0.05) skeletal muscle glucose uptake 20-fold, AMPK phosphorylation 6-fold, ACCbeta phosphorylation 10-fold, and p38 MAPK phosphorylation 60-fold, and the muscle fatigued by approximately 30% during contraction and NAC infusion had no significant effect on any of these responses. This was despite NAC preventing increases in S-glutathionylation with contraction. In conclusion, unlike during highly fatiguing ex vivo contractions, local NAC infusion during in situ low-moderate intensity hindlimb contractions in rats, a more physiological preparation, does not attenuate increases in skeletal muscle glucose uptake or AMPK signaling.