Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024591 (malignant hyperthermia)
 2,353 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This investigation sought to determine if the Ca2+ antagonist, TMB-8, alters the contracture responses of malignant hyperthermia susceptible (MHS) skeletal muscle to halothane and to caffeine. Muscle fiber bundles were excised from both MHS and normal pigs and exposed to TMB-8 (100 microM), halothane (3%) and caffeine (0.5-8.0 mM), administered alone and in combination. TMB-8 depressed tension developed during isometric twitches in both MHS and normal muscle but had no effect on resting tension (RT). Halothane, however, increased RT in MHS but not in normal muscle. TMB-8 failed to reduce the halothane contracture of MHS muscle but hastened its onset. Caffeine concentrations of greater than or equal to 2 mM increased RT in MHS whereas only 8 mM evoked contracture of normal muscle. These effects were also unaltered by TMB-8. Results suggest that TMB-8 does not inhibit halothane nor caffeine contractures of MHS muscle.
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PMID:Effects of the calcium antagonist, TMB-8 on halothane and on caffeine contractures of malignant hyperthermia susceptible skeletal muscle. 238 62

In malignant hyperpyrexia susceptible (MHS) porcine skeletal muscle, a low concentration (100 mumol/l) of the calcium ion antagonist 8-(N,N-diethylamino)-octyl-3,4,5-trimethoxybenzoate (TMB-8) inhibited KCl-induced contractures, but potentiated contractures induced by halothane, caffeine and succinylcholine. Higher concentrations of TMB-8 (333 mumol/l to 1 mmol/l) contracted MHS muscle, but had little effect on muscle tension in control preparations. Treatments which inhibit excitation-contraction coupling abolished TMB-8-induced hyper-reactivity in MHS muscle. TMB-8 (50 mumol/l and 1 mmol/l) did not alter 45Ca2+ levels in actively loaded microsomal preparations from MHS swine. These results suggest that in malignant hyperpyrexia the primary abnormality occurs proximal to the release of calcium from the sarcoplasmic reticulum, probably at the level of excitation-contraction coupling.
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PMID:The effect of the calcium ion antagonist 8-(N,N-diethylamino)-octyl-3,4,5-trimethoxybenzoate on malignant hyperpyrexia-susceptible porcine skeletal muscle. 664 Oct 19