IN VITRO EFFECT OF EPHEDRINE, ADRENALINE, NORADRENALINE AND ISOPRENALINE ON HALOTHANE-INDUCED CONTRACTURES IN SKELETAL MUSCLE FROM PATIENTS POTENTIALLY SUSCEPTIBLE TO MALIGNANT HYPERTHERMIA
URWYLER, A. ; CENSIER, K. ; SEEBERGER, M. D. ; ROTHENBUHLER, J. M. ; KAUFMANN, M. A. ; DREWE, J.
In: BJA: British Journal of Anaesthesia, 1993, vol. 70, no. 1, p. 76-79
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- SUMMARY We have measured the effects of ephedrine, adrenaline, noradrenaline and isoprenaline on halothaneinduced 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 theleft and an increased maximum muscle contracturein 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 investigatedadrenoceptoragonists. (Br. J. Anaesth. 1993; 70:76-79)