Resting membrane potential of rat plantaris muscle fibers after prolonged indirect stimulation in situ: effect of glucose infusion.
The purpose of this study was to determine whether glucose infusion during prolonged indirect muscle stimulation (50 Hz for 200 ms every 2.7 s at 5 V) would have an effect on resting membrane potential (RMP). The RMP measured at Min 1 in the recovery period following stimulation of the rat plantaris muscle for 60 min in situ was significantly decreased in control rats, but was back to baseline values within 2 min. When glucose was infused ([glucose] approximately 10 mM), no change was observed in RMP, and muscle fatigue and the reduction in M-wave peak-to-peak amplitude were both attenuated. However, muscle force and the electrical properties of the membrane were deteriorated both in rats infused with glucose and in control rats at Min 2 during the recovery period, at a time when RMP was not modified. These observations suggest that the effect of increased circulating glucose on fatigue-associated reductions in muscle fiber RMP seems to be modest and short-lived. Therefore, the attenuating effect of elevated glucose on muscle fatigue responses could be through mechanisms other than those associated with maintenance of RMP during fatigue.
Karelis
Antony D
AD
Département de Kinésiologie, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montréal, Québec H3C 3J7.
Péronnet
François
F
Gardiner
Phillip F
PF
D000818:Animals; D004558:Electric Stimulation; D004576:Electromyography / Q000187:drug effects; D005260:Female; D005947:Glucose / Q000008:administration & dosage / Q000494:pharmacology*; D007262:Infusions, Intravenous; D008564:Membrane Potentials / Q000187:drug effects* / Q000502:physiology; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D018763:Muscle Fatigue / Q000187:drug effects / Q000502:physiology; D018485:Muscle Fibers, Skeletal / Q000187:drug effects* / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function / Q000502:physiology; D012584:Sciatic Nerve / Q000502:physiology; D012965:Sodium Chloride; D013997:Time Factors
D012965:Sodium Chloride; D005947:Glucose