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

Merry, T. L and Dywer, R. M and Bradley, E. A and Rattigan, S and McConell, Glenn K (2010) Local hindlimb antioxidant infusion does not affect muscle glucose uptake during in situ contractions in rat. Journal of Applied Physiology, 108 (5). pp. 1275-1283. ISSN 8750-7587

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Abstract

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 ∼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 ∼250 and 150 kDa was increased (P < 0.05) ∼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, ACCβ 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.

Item Type: Article
Uncontrolled Keywords: ResPubID21014, exercise, metabolism, S-glutathionylation, reactive oxygen species, AMP-activated protein kinase
Subjects: Faculty/School/Research Centre/Department > Institute of Sport, Exercise and Active Living (ISEAL)
FOR Classification > 0606 Physiology
SEO Classification > 9201 Clinical Health (Organs, Diseases and Abnormal Conditions)
Depositing User: VUIR
Date Deposited: 27 Aug 2012 01:52
Last Modified: 12 Feb 2015 03:35
URI: http://vuir.vu.edu.au/id/eprint/7008
DOI: 10.1152/japplphysiol.01335.2009
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Citations in Scopus: 6 - View on Scopus

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