Sarcoplasmic reticulum in experimental myotonia in rats.

Determinations of enzymatic activity, protein structure and phospholipid composition of sarcoplasmic reticulum isolated from the soleus muscle (S), extensor digitorum longus muscle (EDL) and gastrocnemius muscle (G) in rats were carried out after various periods of 20,25-diazacholesterol administration. The sarcoplasmic reticulum from G and EDL of myotonic rats exhibited a rise in basal ATP-ase activity and a fall of total phospholipids. The protein of molecular weight of 100000 daltons in G and EDL was slightly more pronounced.