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Local hindlimb antioxidant infusion does not affect muscle glucose uptake during in situ contractions in rat
journal contributionposted on 2023-05-17, 02:57 authored by Merry, TL, Renee RossRenee Ross, Bradley, EA, Stephen RattiganStephen Rattigan, McConell, GK
Local hindlimb antioxidant infusion does not affect muscle glucose uptake during in situ contractions in rat. J Appl Physiol 108: 1275-1283, 2010. First published March 4, 2010; 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 mgkg1h1) 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 (P0.05) plasma cysteine and cystine (by 360- and 1.4-fold, respectively) and muscle cysteine (by 1.5-fold, P0.001). Although contraction did not significantly alter muscle tyrosine nitration, reduced (GSH) or oxidized glutathione (GSSG) content, S-glutathionylation of protein bands at 250 and 150 kDa was increased (P0.05) 1.7-fold by contraction, and this increase was prevented by NAC. Contraction increased (P0.05) skeletal muscle glucose uptake 20-fold, AMPK phosphorylation 6-fold, ACC| phosphorylation 10-fold, and p38 MAPK phosphorylation 60-fold, and the muscle fatigued by 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.
Publication titleJournal of Applied Physiology
Department/SchoolTasmanian School of Medicine
PublisherAmer Physiological Soc
Place of publication9650 Rockville Pike, Bethesda, USA, Md, 20814
Rights statementCopyright © 2010 the American Physiological Society.