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Calcium‐tension relationships of muscle fibers from patients with periodic paralysis
Author(s) -
Ruff Robert L.
Publication year - 1991
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880140907
Subject(s) - calcium , periodic paralysis , paralysis , medicine , tension (geology) , muscle contraction , anatomy , surgery , materials science , composite material , ultimate tensile strength
Abstract Lateral gastrocnemius muscle biopsies from a 26‐year‐old man with hyperkalemic periodic paralysis and a 23‐year‐old man with hypokalemic periodic paralysis were studied. Both patients came from families in which older relatives had developed a vacuolar myopathy in association with their periodic paralysis. Muscle fibers were chemically skinned, and individual fibers were studied with a low‐compliance strain gauge. The tension generated by fibers was studied in baths with calcium concentrations from 10 ‐8 mol/L to 2.5 × 10 ‐5 mol/L. The Ca‐tension relationships and maximal tensions (normalized to fiber cross‐sectional area) of fast and slow twitch fibers were indistinguishable from those found in fibers from 5 normal subjects. The results reinforce earlier findings which suggested that loss of Ca‐induced myofibril contraction was not the cause of paralysis in periodic paralysis.