In vitro effect of ephedrine, adrenaline, noradrenaline and isoprenaline on halothane-induced contractures in skeletal muscle from patients potentially susceptible to malignant hyperthermia.
We have measured the effects of ephedrine, adrenaline, noradrenaline and isoprenaline on halothane-induced contractures in muscle biopsies from patients potentially susceptible to malignant hyperthermia (MH). At concentrations of 4-24 mmol litre-1, ephedrine induced in vitro contractures in halothane 0.44 mmol litre-1-prechallenged muscle, whilst adrenaline, noradrenaline and isoprenaline had no effect. There was a shift of the ephedrine concentration-response curve to the left and an increased maximum muscle contracture in the MH susceptible group compared with the MH negative group (P < 0.001). We conclude that ephedrine increased halothane-induced muscle contractures in vitro either by an unknown pharmacological mechanism or by an adrenergic stimulation which was different from those of the other investigated adrenoceptor agonists.
Urwyler
A
A
Department of Anaesthesia and Research, University of Basel, Kantonsspital, Switzerland.
Censier
K
K
Seeberger
M D
MD
Rothenbühler
J M
JM
Kaufmann
M A
MA
Drewe
J
J
D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004809:Ephedrine / Q000494:pharmacology*; D004837:Epinephrine / Q000494:pharmacology*; D006221:Halothane / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology*; D008305:Malignant Hyperthermia / Q000503:physiopathology*; D009119:Muscle Contraction / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology*
D004809:Ephedrine; D007545:Isoproterenol; D006221:Halothane; D009638:Norepinephrine; D004837:Epinephrine