title: Caffeine impairs intramuscular energy balance in patients susceptible to malignant hyperthermia.
abstract: Malignant hyperthermia (MH) is a metabolic myopathy with an abnormal release of calcium by the sarcoplasmic reticulum (SR), triggered by volatile anesthetics and succinylcholine. Similarly, caffeine enhances Ca(2+)release by the SR in vitro. In a prospective, randomized study, high-energy phosphates were studied by intramuscular 31-phosphorus magnetic resonance spectroscopy ((31)P-MRS) in 10 MH-susceptible (MHS) and 7 MH-nonsusceptible (MHN) subjects before and after injection of 0.5 ml caffeine (20 mM). Intramuscular energy balance, measured by the ratios of P(i)/PCr and P(i)/gamma-ATP, did not differ between MHS and MHN patients before and after intramuscular caffeine injection. However, within each group, P(i)/PCr and P(i)/gamma-ATP increased significantly only in the MHS group. Intramuscular caffeine injection seemed to impair the metabolic balance in MHS individuals. This may reflect a local calcium overload leading to consumption of high-energy phosphates and increase of inorganic phosphate. Intramuscular stimulation by caffeine and (31)P-MRS may provide a valuable tool to investigate MH-related metabolic disturbances.
authors.affiliation: Department of Anesthesiology, University of Würzburg, J-Schneider-Strasse 2, D-97080 Würzburg, Germany.
authors.forename: Zoran
authors.initials: Z
authors.lastname: Textor
authors.forename: Meinrad
authors.initials: M
authors.lastname: Beer
authors.forename: Martin
authors.initials: M
authors.lastname: Anetseder
authors.forename: Herbert
authors.initials: H
authors.lastname: Köstler
authors.forename: Erwin
authors.initials: E
authors.lastname: Kagerbauer
authors.forename: Werner
authors.initials: W
authors.lastname: Kenn
authors.forename: Dietbert
authors.initials: D
authors.lastname: Hahn
authors.forename: Norbert
authors.initials: N
authors.lastname: Roewer
mesh_terms: D000328:Adult; D000367:Age Factors; D002110:Caffeine; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D004198:Disease Susceptibility / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008305:Malignant Hyperthermia / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D008659:Metabolic Diseases / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism* / Q000503:physiopathology; D009135:Muscular Diseases / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D010085:Oxidative Phosphorylation / Q000187:drug effects*; D010725:Phosphocreatine / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism; D010761:Phosphorus Radioisotopes; D011446:Prospective Studies; D011877:Radionuclide Imaging; D012737:Sex Factors
chemical_list: D010761:Phosphorus Radioisotopes; D010725:Phosphocreatine; D010758:Phosphorus; D002110:Caffeine; D002118:Calcium