In Vitro Effect of Ephedrine, Adrenaline, Noradrenaline and Isoprenaline on Halothane-Induced Contractures in Skeletal Muscle From Patients Potentially Susceptible to Malignant Hyperthermia

Abstract

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.

Management of Malignant Hyperthermia Susceptible Parturients

“…There have been no adverse effects from the use of ephedrine clinically (Rosenberg H., personal communication, VIIIth Workshop on Malignant Hyperthermia, Minneapolis 1996). Adrenaline, noradrenaline, isoprenaline and salbutamol have no effect on muscle contractures 43,44 .…”

Ephedra intermedia Schrenk & C. A. Mey Methanol Extract: Nanoencapsulation by Mini‐Emulsion Polymerization and its Release Trend under Simulated Conditions of the Human Body

“…[47][48][49] ii) Indirect activity through the release of noradrenaline from sympathetic neurons. [50][51][52] iii) Activity on unidentified receptors that release dopamine and serotonin in the central nervous system. Ephedrine also stimulates the central nervous system, similar to amphetamines.…”

“… Agonistic activity on α‐ and β‐adrenergic receptors leads to the contraction of vascular smooth muscle, increased cardiac contractile force, increased atrioventricular conduction, hyperglycemia, weakness in intestinal smooth muscle, increased renin secretion, weakness in bronchial smooth muscle, and subsequent bronchial dilation [47–49] Indirect activity through the release of noradrenaline from sympathetic neurons [50–52] Activity on unidentified receptors that release dopamine and serotonin in the central nervous system.…”