title: Effect of caffeine on intrinsic mechanical properties of normal and malignant hyperthermia-susceptible muscle.
abstract: BACKGROUND
  Malignant hyperthermia (MH) is a potentially lethal anesthesic complication. Pathological symptoms develop after exposure to triggering substances. It remains uncertain whether cellular alterations pre-exist. Mechanical properties of isolated muscle bundles were examined before and after exposure to a triggering substance.
  
  
  METHODS
  With prior written consent, muscle bundles of 12 MH-susceptible (MHS) and 56 MH-nonsusceptible (MHN) individuals were examined before and after exposure to incremental doses of caffeine. Mechanical properties (baseline tension, peak tension, time to peak tension, and relaxation time) were measured. Contraction and relaxation derivatives and contraction-relaxation coupling were calculated and analyzed.
  
  
  RESULTS
  Mechanical properties were not different between the groups before caffeine application. Caffeine increased peak tension in both groups and baseline tension only in MHS muscle bundles; relaxation time/derivative and contraction-relaxation coupling were prolonged.
  
  
  CONCLUSIONS
  Cellular changes seen in MH are not pre-existing. Exposure to triggering substance impairs relaxation in MHS muscle.
authors.affiliation: Department of Anesthesiology, University Hospital Regensburg, 93053, Regensburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Metterlein
authors.affiliation: Department of Anesthesiology, Klinikum Frankfurt (Oder), Frankfurt (Oder), Germany.
authors.forename: Edmund
authors.initials: E
authors.lastname: Hartung
authors.affiliation: Department of Anesthesiology, University Hospital Würzburg, Würzburg, Germany.
authors.forename: Norbert
authors.initials: N
authors.lastname: Roewer
authors.affiliation: Department of Anesthesiology, Krankenhaus Landshut Achdorf, Landshut, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Anetseder
mesh_terms: D002110:Caffeine / Q000494:pharmacology*; D003430:Cross-Sectional Studies; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008279:Magnetic Resonance Imaging; D008297:Male; D008305:Malignant Hyperthermia / Q000235:genetics / Q000473:pathology*; D055595:Mechanical Phenomena / Q000187:drug effects*; D009119:Muscle Contraction / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000187:drug effects*; D009154:Mutation / Q000235:genetics; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D019837:Ryanodine Receptor Calcium Release Channel / Q000235:genetics
chemical_list: D010726:Phosphodiesterase Inhibitors; D019837:Ryanodine Receptor Calcium Release Channel; D002110:Caffeine
keywords: caffeine; calcium; malignant hyperthermia; mechanical properties; muscle