Format

Send to

Choose Destination
See comment in PubMed Commons below
Neuromuscul Disord. 2012 Dec;22 Suppl 3:S168-71. doi: 10.1016/j.nmd.2012.10.011.

Mechanisms of exertional fatigue in muscle glycogenoses.

Author information

1
Neuromuscular Research Unit, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark. vissing@rh.dk

Abstract

Exertional fatigue early in exercise is a clinical hallmark of muscle glycogenoses, which is often coupled with painful muscle contractures and episodes of myoglobinuria. A fundamental biochemical problem in these conditions is the impaired generation of ATP to fuel muscle contractions, which relates directly to the metabolic defect, but also to substrate-limited energy deficiency, as exemplified by the "second wind" phenomenon in McArdle disease. A number of secondary events may also play a role in inducing premature fatigue in glycogenoses, including (1) absent or blunted muscle acidosis, which may be important for maintaining muscle membrane excitability by decreasing chloride permeability, (2) loss of the osmotic effect related to lactate accumulation, which may account for absence of the normal increase in water content of exercised muscle, and thus promote higher than normal concentrations of extracellular potassium in exercising muscle and (3) exaggerated accumulation of ADP during exercise that may inhibit sodium-potassium and calcium-ATPases. Disorders of muscle glycogenolysis and glycolysis reveal the crucial role of these metabolic processes for supplying both anaerobic and aerobic energy for muscle contraction; and the pathological fatigue that occurs when glycogenolysis and/or glycolysis is blocked imply an important role for theses metabolic pathways in normal muscle fatigue.

PMID:
23182633
DOI:
10.1016/j.nmd.2012.10.011
[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Support Center