| First Author | Chin ER | Year | 2014 |
| Journal | Am J Physiol Cell Physiol | Volume | 307 |
| Issue | 11 | Pages | C1031-8 |
| PubMed ID | 25252949 | Mgi Jnum | J:223589 |
| Mgi Id | MGI:5659792 | Doi | 10.1152/ajpcell.00237.2013 |
| Citation | Chin ER, et al. (2014) Perturbations in intracellular Ca2+ handling in skeletal muscle in the G93A*SOD1 mouse model of amyotrophic lateral sclerosis. Am J Physiol Cell Physiol 307(11):C1031-8 |
| abstractText | Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by skeletal muscle atrophy and weakness, ultimately leading to respiratory failure. The purpose of this study was to assess changes in skeletal muscle excitation-contraction (E-C) coupling and intracellular Ca(2+) handling during disease progression in the G93A*SOD1 ALS transgenic (ALS Tg) mouse model. To assess E-C coupling, single muscle fibers were electrically stimulated (10-150 Hz), and intracellular free Ca(2+) concentration was assessed using fura-2. There were no differences in peak fura-2 ratio at any stimulation frequency at 70 days (early presymptomatic). However, at 90 days (late presymptomatic) and 120-140 days (symptomatic), fura-2 ratio was increased at 10 Hz in ALS Tg compared with wild-type (WT) fibers (0.670 +/- 0.02 vs. 0.585 +/- 0.02 for 120-140 days; P < 0.05). There was also a significant increase in resting fura-2 ratio at 90 days (0.351 +/- 0.008 vs. 0.390 +/- 0.009 in WT vs. ALS Tg; P < 0.05) and 120-140 days (0.374 +/- 0.001 vs. 0.415 +/- 0.003 in WT vs. ALS Tg; P < 0.05). These increases in intracellular Ca(2+) in ALS Tg muscle were associated with reductions in the sarcoplasmic/endoplasmic reticulum Ca(2+) ATPase proteins SERCA1 (to 54% and 19% of WT) and SERCA2 (to 56% and 11% of WT) and parvalbumin (to 80 and 62% of WT) in gastrocnemius muscle at 90 and 120-140 days, respectively. There was no change in dihydropyridine receptor/l-type Ca(2+) channel at any age. Overall, these data demonstrate minimal changes in electrically evoked Ca(2+) transients but elevations in intracellular Ca(2+) attributable to decreased Ca(2+)-clearance proteins. These data suggest that elevations in cellular Ca(2+) could contribute to muscle weakness during disease progression in ALS mice. |
