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ULTRASTRUCTURE OF THE MUSCLE SPINDLE IN DYSTROPHIA MYOTONICA. II. THE SENSORY AND MOTOR NERVE TERMINALS
Author(s) -
STRANOCK S. D.,
DAVIS J. NEWSOM
Publication year - 1978
Publication title -
neuropathology and applied neurobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.538
H-Index - 95
eISSN - 1365-2990
pISSN - 0305-1846
DOI - 10.1111/j.1365-2990.1978.tb01352.x
Subject(s) - sensory system , free nerve ending , axoplasm , anatomy , muscle spindle , ultrastructure , sensory nerve , motor nerve , biology , neuroscience , axon , terminal nerve , afferent , endocrinology , hormone
The normal pattern of innervation was lost in the four dystrophia myotonica muscle spindles examined. There had been a proliferation of both sensory and motor nerve terminals, and many endings showed varying degrees of structural abnormality. The changes seen in the sensory nerve endings were an incomplete contact relationship between the terminal and the muscle fibre, the association of Schwann cell processes with the nerve ending, abnormal shape of the terminal, multiple sensory endings, and changes in the ultrastructural organization of the terminal axoplasm. Remnants of degenerated sensory terminals, and isolated sensory endings were also seen. Motor nerve terminals varied in size and shape. In general, they contained a normal complement of vesicles and mitochondria. Junctional folding was often absent or simplified, and sarcoplasmic specialization was, at the most, rudimentary. The relationship between these changes and intrafusal muscle fibre fragmentation is discussed.