Article

Pflügers Archiv

, Volume 338, Issue 3, pp 257-272

First online:

Effects of long-term electrical stimulation on some contractile and metabolic characteristics of fast rabbit muscles

  • Dirk PetteAffiliated withDepartment of Physiology, The Medical SchoolFachbereich Biologie, Universität Konstanz
  • , Margaret E. SmithAffiliated withDepartment of Physiology, The Medical SchoolFachbereich Biologie, Universität Konstanz
  • , Hans W. StaudteAffiliated withDepartment of Physiology, The Medical SchoolFachbereich Biologie, Universität Konstanz
  • , Gerta VrbováAffiliated withDepartment of Physiology, The Medical SchoolFachbereich Biologie, Universität Konstanz

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Summary

Intermittant long-term stimulation of fast rabbit muscles up to 28 days with a frequency pattern resembling that of a slow muscle (10 Imp/sec) led to a slowing of the time course of contraction already during the first week. There was an increase of tetanic tension as well. The observed rearrangement of activities of key enzymes of energy supplying metabolism was found to occur sequentially. Decreases of extramitochondrial enzymes of glycogenolysis (phosphorylase), glycolysis (triosephosphate dehydrogenase, lactate dehydrogenase) and energy rich phosphate transfer were found initially together with a decrease of mitochondrial glycerolphosphate dehydrogenase. The isozyme pattern of lactate dehydrogenase was changed. Large initial increases were found in enzymes involved in glucose phosphorylation (hexokinase) and fatty acid activation (palmitoyl-CoA synthetase). Later an increase of key enzymes of the citric acid cycle (citrate synthase) and fatty acid oxidation (3-hydroxyacyl-CoA dehydrogenase) as well as ketone body utilization (3-ketoacid-CoA transferase) could be shown.

Histochemical staining and comparative activity determination of succinate dehydrogenase in single fibres revealed that the mosaic like fibre composition of the fast muscle was transformed into a more uniform population resembling that of a predominantly slow muscle.

Key words

Nerve-Muscle Interaction Contractile Parameters Energy Supplying Metabolism Transformation of Fibre Types Enzyme Induction