Skip to main content
padlock icon - secure page this page is secure

GLYCOGEN CONTENT AND CONTRACTILE RESPONSIVENESS TO T-SYSTEM DEPOLARIZATION IN SKINNED MUSCLE FIBRES OF THE RAT

Buy Article:

$52.00 + tax (Refund Policy)

SUMMARY

1. Glycogen content (determined microfluorometrically), response capacity to transverse tubular (T) system depolarization and the relationship between these two parameters were examined in single, mechanically skinned fibres from rat extensor digitorum longus (EDL) muscle in the presence of high and constant concentrations of ATP and creatine phosphate.

2. The mean total glycogen content (tGlyc) in freshly dissected fibres was 58.1 ± 4.2 mmol glucosyl units/L fibre (n = 53).

3. A large proportion of tGlyc was retained in the skinned fibres (SFGlyc) after 2 and 30 min exposure to an aqueous relaxing solution (73.1 ± 2.8 and 64 ± 12.3%, respectively).

4. When fibres were incubated for 30 min in a high (30 µmol/L)-Ca2+ solution, the proportion of SFGlyc was markedly lower (approximately 28%), which suggests that rat skinned fibres contain a Ca2+_sensitive glycogenolytic system.

5. In rat skinned fibres, T-system depolarization-induced Ca2+ release was not accompanied by a detectable loss of fibre glycogen and there was no correlation between response capacity and initial SFGlyc, indicating that other factors, unrelated to glycogen depletion, ultimately limited the capacity of rat skinned fibres to respond to T-system depolarization.

6. It is concluded that rat mechanically skinned fibre preparations are well suited for studies of glycogenolysis at a cellular level and that, with further refinement of the depolarization protocol, they may be suitable for studies of the non-metabolic role of glycogen in mammalian skeletal muscle contractility.
No References
No Citations
No Supplementary Data
No Article Media
No Metrics

Keywords: excitation–contraction coupling; fatigue; glycogen metabolism; glycogenolysis; microfluorometry; muscle contraction; single fibre; skeletal muscle

Document Type: Original Article

Affiliations: Muscle Cell Biochemistry Laboratory, School of Biomedical Sciences, Victoria University, Melbourne, Victoria, Australia

Publication date: September 1, 2005

  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more