Myoplasic free [Ca2+] during a malignant hyperthemria episode in swine

J. R. Lopez, P. D. Allen, L. Alamo, D. Jones, F. A. Sreter

Research output: Contribution to journalArticlepeer-review

70 Scopus citations


Malignant hyperthermia (MH) is a genetic syndrome usually initiated by exposure to volatile anesthetic agents or depolarizing neuromusclar blocking agents. We have used Ca2+-selective microelectrodes to measure in vivo the intracellular ionized calcium ([Ca2+](i)) in skeletal muscle fibers of MH-susceptible swines before and during hyperthermic episodes and also after dantrolene administration. The animals were anesthetized with thiopental and fentanyl and maintained with a mixture of nitrous oxide (66%) and oxygen (34%). The malignant hyperthermic episode was triggered by exposure to halothane. Determinations of [Ca2+](i) during the episode show an increase from 0.44 ± 0.01 μM ± SEM, n = 20) to 8.44 ± 0.68 μM (mean ± SEM, n = 10). Administration of dantrolene (2 mg/kg) during the hyperthermic episode reduces [Ca2+](i) to 0.17 = 0.01 μM (mean ± SEM, n = 10) and reverses the clinical symptoms. These results show that the MH episode is associated with an increase in the myoplasmic free Ca2+ concentration and that the therapeutic effect of dantrolene is related to a decrease in [Ca2+](i).

Original languageEnglish (US)
Pages (from-to)82-88
Number of pages7
JournalMuscle and Nerve
Issue number1
StatePublished - 1988
Externally publishedYes

ASJC Scopus subject areas

  • Clinical Neurology
  • Neuroscience(all)


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