3,5-Di-t-butyl catechol is a potent human ryanodine receptor 1 activator, not suitable for the diagnosis of malignant hyperthermia susceptibility.

3,5-Di-t-butyl catechol (DTCAT) releases Ca(2+) from rat skeletal muscle sarcoplasmic reticulum (SR) vesicles. Hence, it is a candidate for use as a substitute for halothane or caffeine in the in vitro contracture test for the diagnosis of susceptibility to malignant hyperthermia (MH). To characterize the effect of DTCAT at cell level, Ca(2+) release experiments were performed on cultured, human skeletal muscle myotubes using the fluorescent Ca(2+) indicator fura2-AM.

Lost in translation: regulation of skeletal muscle protein synthesis.

Skeletal muscle accounts for about 50% of the body's mass in higher vertebrates. Besides its obvious role in motor activity, it also can serve as a reservoir for amino acids during times of starvation, or even as a metabolic water supply for migratory birds' during long flights. An imbalance between anabolic and catabolic processes can lead to the loss of muscle mass and life-threatening cachexia or sarcopenia.

Novel double and single ryanodine receptor 1 variants in two Austrian malignant hyperthermia families.

Background: Malignant hyperthermia (MH) is a potentially lethal genetic disorder in response to volatile anesthetics and depolarizing muscle relaxants. To support the claim that a novel genetic variant causes MH, it is necessary to demonstrate that it has significant effects on the sensitivity of the ryanodine receptor (RYR1) calcium channel. In this study we focused on 2 Austrian families with strong MH disposition and new RYR1 variants.

Novel ryanodine receptor mutation that may cause malignant hyperthermia.

Background: Malignant hyperthermia (MH) is a hypermetabolic condition caused by a genetic disposition leading to increased Ca release from the sarcoplasmic reticulum after exposure to triggering agents. In the authors' ongoing evaluation of patients undergoing MH testing in Austria, they detected a family with a new variant of the ryanodine receptor 1. Guidelines suggest that genetic tests are possible only for individuals from families in which the mutations are known.

4-chloro-m-cresol cannot detect malignant hyperthermia equivocal cells in an alternative minimally invasive diagnostic test of malignant hyperthermia susceptibility.

Malignant hyperthermia (MH) is an inherited skeletal muscle disorder triggered by commonly used anesthetics. Mutated ryanodine receptors have been identified as molecular targets. The sensitivity of myotubes from individuals classified by the in vitro contracture test as MH susceptible (MHS), normal (MHN), and equivocal (MHEH) was assessed for the Ca2+-releasing activity of 4-chloro-m-cresol (4-CmC) and caffeine.

The sensitivity of G protein-activated K+ channels toward halothane is essentially determined by the C terminus.

G protein-activated K(+) channels (GIRKs or Kir3.x) are targets for the volatile anesthetic, halothane. When coexpressed with the m(2) acetylcholine (ACh) receptor in Xenopus oocytes, agonist-activated GIRK1(F137S)- and GIRK2-mediated currents are inhibited by halothane, whereas in the absence of ACh, high concentrations of halothane induce GIRK1(F137S)-mediated currents.