Contractile and histochemical properties of skeletal muscles in hibernating and awake golden hamsters

Abstract

1. Parameters of the isometric twitch contraction in vitro (latency period, maximal rate of tension development, contraction and relaxation time) and the histochemical muscle fibre pattern of the fast extensor digitorum longus, the slow soleus and the diphragm muscles were determined in awake and hibernating golden hamster. 2. Differences of contraction properties between fast and slow muscles are maintained at both 22°C and 37°C in muscles of hibernating hamsters. Hibernation did not affect the temperature dependence of contraction properties of fast and slow musles. 3. During hibernation the muscle fibre pattern of all the muscles tested is maintained with respect to ATP-ase and phosphorylase activity, it becomes, however, more uniform and there is an increase in activity of oxidative enzymes (succinic dehydrogenase).