caa a22 4500 475744934 CHVBK 20180406123510.0 cr unu---uuuuu 170329e20001001xx s 000 0 eng 10.1023/A:1005628500892 doi (NATIONALLICENCE)springer-10.1023/A:1005628500892 Glycogen stability and glycogen phosphorylase activities in isolated skeletal muscles from rat and toad [Elektronische Daten] [Craig Goodman, Gabriela Stephenson] There is increasing evidence that endogenous glycogen depletion may affect excitation-contraction (E-C) coupling events in vertebrate skeletal muscle. One approach employed in physiological investigations of E-C coupling involves the use of mechanically skinned, single fibre preparations obtained from tissues stored under paraffin oil, at room temperature (RT: 20-24°C) and 4°C for several hours. In the present study, we examined the effect of these storage conditions on the glycogen content in three muscles frequently used in research on E-C coupling: rat extensor digitorum longus (EDL) and soleus (SOL) and toad iliofibularis (IF). Glycogen content was determined fluorometrically in homogenates prepared from whole muscles, stored under paraffin oil for up to 6 h at RT or 4°C. Control muscles and muscles stored for 0.5 and 6 h were also analysed for total phosphorylase (Phostotal) and phosphorylase a (Phos a) activities. No significant change was observed in the glycogen content of EDL and SOL muscles stored at RT for 0.5 h. In rat muscles stored at RT for longer than 0.5 h, the glycogen content decreased to 67.6% (EDL) and 78.7% (SOL) of controls after 3 h and 25.3% (EDL) and 37.4% (SOL) after 6 h. Rat muscles stored at 4°C retained 79.0% (EDL) and 92.5% (SOL) of glycogen after 3 h and 75.2% (EDL) and 61.1% (SOL) after 6 h. The glycogen content of IF muscles stored at RT or 4°C for 6 h was not significantly different from controls. Phostotal was unchanged in all muscles over the 6 h period, at both temperatures. Phos a was also unchanged in the toad IF muscles, but in rat muscles it decreased rapidly, particularly in EDL (4.1-fold after 0.5 h at RT). Taken together these results indicate that storage under paraffin oil for up to 6 h at RT or 4°C is accompanied by minimal glycogen loss in toad IF muscles and by a time- and temperature-dependent glycogen loss in EDL and SOL muscles of the rat. Kluwer Academic Publishers, 2000 Goodman Craig Muscle Cell Biochemistry Laboratory, School of Life Sciences and Technology, Victoria University, P.O. Box 14428 MCMC, 8001, Melbourne, Victoria, Australia aut Stephenson Gabriela Muscle Cell Biochemistry Laboratory, School of Life Sciences and Technology, Victoria University, P.O. Box 14428 MCMC, 8001, Melbourne, Victoria, Australia aut Journal of Muscle Research & Cell Motility Kluwer Academic Publishers 21/7(2000-10-01), 655-662 0142-4319 21:7<655 2000 21 10974 https://doi.org/10.1023/A:1005628500892 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1005628500892 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Goodman Craig Muscle Cell Biochemistry Laboratory, School of Life Sciences and Technology, Victoria University, P.O. Box 14428 MCMC, 8001, Melbourne, Victoria, Australia aut NATIONALLICENCE 700 1- Stephenson Gabriela Muscle Cell Biochemistry Laboratory, School of Life Sciences and Technology, Victoria University, P.O. Box 14428 MCMC, 8001, Melbourne, Victoria, Australia aut NATIONALLICENCE 773 0- Journal of Muscle Research & Cell Motility Kluwer Academic Publishers 21/7(2000-10-01), 655-662 0142-4319 21:7<655 2000 21 10974 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer