The effects of glycerol and urea on the ultrastructure and contractility of fast and slow rat skeletal muscles

S A Krolenko, D O Karpenko
1983 General Physiology and Biophysics  
The influence of the influx and efflux of glycerol and urea (400 mmol/l) on the amplitude of isometric twitches and the ultrastructure of isolated fast (EDL) and slow (SOL) muscles of young rats was studied. The influx of non-electrolytes was accompanied by a temporary decrease in the twitch tension. The removal of non-electrolytes resulted in a stable reduction of twitches. Both effects were less pronounced in glycerol experiments on slow muscles. The inhibition of twitches after the removal
more » ... after the removal of non-electrolytes was associated with selective alterations of the T-system: swelling, vacuolation, and lysis of T-tubules. Quantitative analysis of the T-system showed that the extent of these changes may vary for different fibres, and the intensity of morphological alteration of the T-system generally correlated with the degree of twitch inhibition. Reloading of muscles with non-electrolytes tended to improve the T-system structure in some fibres and led to a partial restoration of the amplitude of twitches.
pmid:6678774 fatcat:6advbztmkrfjpfmq5nfc423pfa