TOXIC AND NEUROGENIC FACTORS IN CHLOROQUINE MYOPATHY FIBER SELECTIVITY

Biopsies from soleus and extensor digitorum longus (EDL) muscles obtai ned in rats with an chloroquine myopathy were studied ultrastructurall y. Two different histopathological pictures were observed: type I fibr es from soleus exhibited a vacuolar myopathy with an almost normal sar comeric structure; type II fibres from EDL did not show vacuoles but c hanges similar to neurogenic atrophy. Our results suggest that chloroq uine produces direct toxic effects in type I fibres and secondary neur ogenic damage in type II fibres.