sodium-perchlorate and Muscular-Dystrophy--Animal

The effects of perchlorate (6-40 mM) on contractile properties and depolarization-contraction coupling of diaphragm have been tested in muscle fibre bundles from 8 to 12-week-old mdx and control mice. Twitch contractile properties were affected by perchlorate to a similar extent in mdx and control muscles. In the absence of perchlorate, voltage-dependent parameters of both activation and inactivation were similar in mdx and control muscles. In both mdx and control muscles, perchlorate induced a shift of activation and inactivation curves toward more negative potentials. However, mdx diaphragm fibres were less sensitive to perchlorate in the low range of concentrations (6-12 mM). These results are unlikely to be due to a possible effect of the lack of dystrophin on the excitation-contraction coupling voltage sensor or ryanodine receptor. However, necrosis and regeneration occur in mdx mouse diaphragm and it is postulated that the presence of a high proportion of not fully mature fibres could contribute to the reduced sensitivity of mdx diaphragm fibres to perchlorate.

Topics: Animals; Calcium Channels; Diaphragm; In Vitro Techniques; Male; Membrane Potentials; Mice; Mice, Inbred C57BL; Mice, Inbred mdx; Muscle Contraction; Muscle Proteins; Muscular Dystrophy, Animal; Perchlorates; Potassium; Ryanodine Receptor Calcium Release Channel; Sodium Compounds