Complexes of annulate lamellae and nemaline bodies in soleplate nuclei in skeletal muscle fibers of the normal rat

Pseudointranuclear inclusions resulting from invaginations of the nuclear envelope, characteristic of myopathic muscles, were found in the soleplate nuclei of normal soleus muscles of rats. Such inclusions had annulate lamellae (AL), nemaline or rod bodies, lamellar structures, a concentric system of membranes, as well as tightly packed sarcoplasmic organelles. An accumulative origin of such included structures was suggested. The AL were sometimes connected directly to the outer membrane enclosing the inclusions, dilated into cisterns and positioned perpendicularly against the nuclear surface. AL, some of which were well-developed, were observed in the same loci as above during the course of denervation atrophy.