Nerve stimulation decreases malonyl-CoA in skeletal muscle.
This study was designed to determine the effect of in situ electrical stimulation of the sciatic nerve on malonyl-CoA, an inhibitor of carnitine palmitoyl transferase, in the gastrocnemius/plantaris muscle group of rats. The left sciatic nerve was stimulated at a frequency of 5 Hz with 100-ms trains of impulses (50 Hz) for 1, 3, or 5 min. At the end of stimulation, the left and right (nonstimulated) gastrocnemius/plantaris muscle groups were clamp-frozen and later analyzed for malonyl-CoA and other metabolites. No change was observed in the noncontracting contralateral muscles in malonyl-CoA, ATP, creatine phosphate (CP), or citrate. In the stimulated muscles, malonyl-CoA decreased from 1.7 +/- 0.1 to 1.0 +/- 0.1 nmol/g (P less than 0.05), and CP decreased from 15.8 +/- 0.9 to 12.2 +/- 1.0 mumol/g (P less than 0.05) after 3 min of stimulation. After 5 min of stimulation, malonyl-CoA was 1.0 +/- 0.1 nmol/g and CP was 10.3 +/- 1.3 mumol/g. When muscles were stimulated for 5 min with single impulses (5 Hz), malonyl-CoA was decreased from 1.8 +/- 0.3 to 1.0 +/- 0.1 nmol/g, with no change in CP, ATP, or adenosine 3',5'-cyclic monophosphate. Thus a decline in malonyl-CoA can be induced by muscle contraction independently of humoral influence.
Duan
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Department of Zoology, Brigham Young University, Provo, Utah 84602.
Winder
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D000103:Acetyl-CoA Carboxylase / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002951:Citrates / Q000378:metabolism; D019343:Citric Acid; D000242:Cyclic AMP / Q000378:metabolism; D004558:Electric Stimulation; D008297:Male; D008316:Malonyl Coenzyme A / Q000378:metabolism*; D009119:Muscle Contraction / Q000502:physiology; D009132:Muscles / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012584:Sciatic Nerve / Q000502:physiology
D002951:Citrates; D019343:Citric Acid; D008316:Malonyl Coenzyme A; D000255:Adenosine Triphosphate; D000242:Cyclic AMP; D000103:Acetyl-CoA Carboxylase