| First Author | Heller A | Year | 1981 |
| Journal | Mouse News Lett | Volume | 65 |
| Pages | 16 | Mgi Jnum | J:13894 |
| Mgi Id | MGI:62072 | Citation | Heller A, et al. (1981) Myotonia (mto). Mouse News Lett 65:16 |
| abstractText | Full text of MNL contribution: 1. Myotonia (mto). This autosomal recessive mutation arose at the Jackson Laboratory in the SWR/J strain and is under study by Dr. Eva Eicher and ourselves. Outcrossed homozygous affected mice are recognized at two weeks of age or earlier, when they show unusually prolonged stiff extensor postures of limbs when the cage is shaken or the mouse dropped from a height of about 10 cm onto its feet. Repeated testing may lead t o lessening of the abnormal responses, but the full defect is expressed again after a few moments of rest. Electromyographic studies with concentric needle electrodes revealed myotonic discharges (repetitive firing at varying amplitude and frequency, with the characteristic dive-bomber sound from the speaker) in all limb, abdominal and tongue muscles tested at all ages from four to 44 weeks. Myotonic discharges were elicited also with needle insertion or by percussion or stretching of the test muscle. Myotonia is a feature of several inherited human diseases and, at the cell level, is usually considered to reflect a muscle fiber with an electrically unstable membrane caused by decreased chloride conductance. (Heller, Sidman) |
