Light microscopic demonstration of myoid fibres in the nervous system

Abstract

In 1968 Puszkin and co-workers isolated from brain an actomyosin-like protein which was not derived from the vascular system. Since corresponding myofibrils had not been described in histology, the tannic acid-phosphomolybdic acid-Levanol Fast Cyanine 5RN stain for myosin and related proteins was applied to methacarn-fixed paraffin sections of human central nervous system (CNS) and peripheral nerve. Extensive meshworks of myoid fibres were found in the marginal layer and in white matter. Spider-like cells containing myoid fibres were found in some areas of grey matter. Many axons of peripheral nerves were surrounded by 'myoid material, but myelin sheaths in CNS were apparently extracted by the fixative.Correlation of these observations with histochemical, electron microscopic and X-ray diffraction data indicated similarity of the distribution of myoid fibres and fibrous astrocytes ; the astrocyte fibres show the X-ray diffraction pattern of a-helical proteins. The myoid material in peripheral nerve is apparently associated with the myelin sheath. This pilot study suggests that the actomyosinlike protein isolated from brain is probably derived from glia fibres which show the staining and X-ray diffraction properties of proteins of the myosin-fibrin group.

Molecular Genetic Classification of Central Nervous System Malformations

“…Striated myofibers with well-formed sarcomeres sometimes differentiate at various sites within the human central nervous system, where their contractile function is of no use. 44,45 Muscle also develops at times in the brains of other mammals : in the infundibulum of the monkey,46 in the pineal of swine,~7 and in the cerebellum of the rat.~8 Actomyosin proteins also are isolated biochemically from mammalian brain.49 This muscle differentiation occurs at times in apparently normal brains, but is much more frequent in cerebral dysgenesis. Muscle formation in the spinal or cerebral leptomeninges also is demonstrated, both in humans50,51 and in other mammals.52 Whether ectopic myofibers in the brain or meninges are innervated and, if so, from what source is unknown.…”

A Modified Levanol Fast Cyanine 5Rn Staining Method For Myoepithelial Cells

“…Levanol Fast Cyanine 5RN, in certain circumstances, can be used for the staining of myosin, but fibrin, keratin, true elastic fibres (Puchtler et al, 1969a), glia fibres (Waldrop et al, 1972) and nuclei (Waldrop et al, 1976) possess the same staining affinities. Accordingly, the major problem is to obtain a satisfactory selectivity by decreasing the binding on less desirable structures as nuclei.…”