An electromyographic study of myotonia

Floyd, W. F.; Kent, Peter D.; Page, Francis

doi:10.1016/0013-4694(55)90088-2

Cited by 29 publications

(8 citation statements)

References 11 publications

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“…Muscle membrane has been implicated as the site of the physiological defect. After nerve block or isolation of myotonic muscle in vitro, repetitive depolarization of myotonic muscle can still be elicited (14)(15)(16)(17). Recent studies have demonstrated abnormal cable properties in muscle from patients with myotonia congenita, but the only electrophysiologic correlate observed in muscle from myotonic dystrophy patients was an increase in total fiber capacitance (43).…”

Section: Discussionmentioning

confidence: 99%

“…Physiological investigations have suggested a membrane abnormality as the underlying metabolic defect. Repetitive depolarization of myotonic muscle fibers, even after nerve block or neuromuscular blockade, has led many investigators to localize the defect to the muscle sarcolemma (14)(15)(16)(17). No abnormalities in muscle contractile proteins (18) or in "relaxing factor" (19) have been demonstrated in myotonic muscle tissue.…”

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confidence: 99%

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Protein Kinase Activity in Erythrocyte Ghosts of Patients with Myotonic Muscular Dystrophy

Roses

Appel

1973

Proc. Natl. Acad. Sci. U.S.A.

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Myotonic muscular dystrophy is a disorder of humans that involves many organ systems. Physiological studies have suggested that the fundamental defect is of membrane origin. Heretofore, no reproducible metabolic abnormalities have been demonstrated. In the present studies we used erythrocyte ghosts as a convenient source of purified membranes that do not possess changes of denervation, dystrophy, and fibrosis that might complicate the interpretation of muscle membrane changes. Our experiments demonstrated a significant difference in the phosphorylation of erythrocyte ghost protein by [y_32PJATP, with endogenous protein kinase of erythrocyte membrane as the enzyme source. After ghosts were kept for 1 week at -20°, phosphorylation of membrane protein in eight controls was twice as high as endogenous protein kinase activity measured in fresh preparations. No stimulation was seen in preparations from seven myotonic dystrophy patients from three different families. This reproducible difference in normal and myotonic membranes may represent an important new approach to studies of this debilitating inborn error of metabolism.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Protein Kinase Activity in Erythrocyte Ghosts of Patients with Myotonic Muscular Dystrophy

Roses

Appel

1973

Proc. Natl. Acad. Sci. U.S.A.

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“…Evidence of a central nervous system component in myotonia was also found by Denny- Brown and Nevin (1941) and they showed that this was responsible for the phenomenon of afterspasm. On the other hand, the most striking electrophysiological feature of myotonic muscle, the rapid burst of action potentials which gradually lessens in frequency (dive bomber potentials), is a property of the muscle fibre membrane itself, since studies in man and in animals have shown that it resists not only motor nerve block but also curarization (Brown ' and Harvey, 1939;Floyd, Kent, and Page, 1955;McComas and Mossawy, 1965).…”

Section: Muscular Dystrophy Laboratories Newcastle General Hospitalmentioning

confidence: 99%

The electrical properties of muscle fiber membranes in dystrophia myotonica and myotonia congenita.

McComas¹,

Mrozek²

1968

Journal of Neurology, Neurosurgery & Psychiatry

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“…These potentials do not depend on motor neurone activity since they occur independently of willed movement and persist after impulse conduction in motor axons has been blocked (Buchthal and Clemmesen, 1941). The fact that d-tubocurarine is also ineffective in abolishing the action potentials (Floyd, Kent, and Page, 1955) indicates that they are not caused by acetylcholine acting at the end-plate or elsewhere along the fibre surface but must result from some intrinsic abnormality of the muscle fibre membrane.…”

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confidence: 99%