These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Abnormal uptake and release of Ca2+ ions from human malignant hyperthermia-susceptible sarcoplasmic reticulum.
    Author: O'Sullivan GH, McIntosh JM, Heffron JJ.
    Journal: Biochem Pharmacol; 2001 Jun 15; 61(12):1479-85. PubMed ID: 11377377.
    Abstract:
    Malignant hyperthermia (MH) is a pharmacogenetic myopathy that occurs in humans and several other mammalian species. There has been limited investigation of Ca2+ transport by human heavy sarcoplasmic reticulum (HSR) vesicles despite the fact that mutations of the ryanodine receptor Ca2+ release channel have been linked to inheritance of MH. In this study, the Ca2+ release and uptake mechanisms in human MH-susceptible HSR (MHS) vesicles were investigated and the kinetics and sensitivity compared to normal vesicles. Alterations in Ca2+ regulation were thereby elucidated. HSR vesicles from 6 normal (MHN) and 5 MHS patients were compared using a dual-wavelength continuous Ca2+ flux assay in the presence of pyrophosphate. The loading capacity and loading rate of Ca2+ in MHS vesicles were reduced by almost 50%. These parameters were restored to normal when the Ca2+ channel blocker ruthenium red was added. Calcium-induced calcium release, halothane-induced calcium release, and trifluoperazine-induced calcium release were clearly elevated in MHS HSR vesicles compared to MHN vesicles. The results suggest that MH ryanodine receptors exist in a more open resting state than those in normal muscle.
    [Abstract] [Full Text] [Related] [New Search]