AMP-activated protein kinase response to contractions and treatment with the AMPK activator AICAR in young adult and old skeletal muscle.

Thomson DM, Brown JD, Fillmore N, Ellsworth SK, Jacobs DL, Winder WW, Fick CA, Gordon SE
J Physiol. 2009 587 (Pt 9): 2077-86

PMID: 19273578 · PMCID: PMC2689345 · DOI:10.1113/jphysiol.2008.166512

One characteristic of ageing skeletal muscle is a decline in mitochondrial function. Activation of AMP-activated protein kinase (AMPK) occurs in response to an increased AMP/ATP ratio, which is one potential result of mitochondrial dysfunction. We have previously observed higher AMPK activity in old (O; 30 months) vs young adult (YA; 8 months) fast-twitch muscle in response to chronic overload. Here we tested the hypothesis that AMPK would also be hyperactivated in O vs YA fast-twitch extensor digitorum longus muscles from Fischer(344) x Brown Norway (FBN) rats (n = 8 per group) in response to high-frequency electrical stimulation of the sciatic nerve (HFES) or injection of AICAR, an activator of AMPK. Muscles were harvested immediately after HFES (10 sets of six 3-s contractions, 10 s rest between contractions, 1 min rest between sets) or 1 h after AICAR injection (1 mg (g body weight)(-1) subcutaneously). The phosphorylations of AMPKalpha and acetyl-CoA carboxylase (ACC2; a downstream AMPK target) were both greatly increased (P

MeSH Terms (10)

Aging Aminoimidazole Carboxamide AMP-Activated Protein Kinases Animals Enzyme Activation Muscle Contraction Rats Rats, Inbred F344 Ribonucleotides Signal Transduction

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