MYOPLASMIC CA2+ CONCENTRATION DURING EXERTIONAL RHABDOMYOLYSIS

Exertional rhabdomyolysis can destroy muscle but the pathophysiology i s unknown. Using intracellular selective microelectrodes, we found tha t intracellular Ca2+ concentration ([Ca2+]i) was 1.27 (0.17) mu mol/L (median and interquartile range) in skeletal-muscle biopsy specimens f rom patients with exertional rhabdomyolysis compared with 0.12 (0.01) mu mol/L in controls. 3 days treatment with dantrolene, a drug that in hibits Ca2+ release from the sarcoplasmic reticulum, decreased [Ca2+]i to 0.22 (0.05) mu mol/L and accelerated patients' recovery. This stud y demonstrated that exertional rhabdomyolysis is associated with eleva ted [Ca2+]i, and that dantrolene has a beneficial effect in this syndr ome.