Contraction of rat skeletal muscle after glycerol treatments.

The effects of glycerol (400 to 1,200 mM) treatment on contractions of rat soleus muscles were investigated. Glycerol induced temperature- and concentration-dependent contractures which depended largely on extracellular calcium. Glycerol treatments reduced but did not abolish twitch, tetanus, and potassium contracture tension and these changes were far less at 22 than at 37 degrees C. Caffeine contractures were not altered following glycerol treatment at 22 degrees C, but were at 37 degrees C. It is suggested that the lesser effects of glycerol treatment on the soleus compared to other muscles may be due to its smaller transverse tubule system. Glycerol permeation and thus its osmotic action may be less in the soleus than in other muscles.