3,5-Di-t-butyl catechol (DTCAT) as an activator of the human skeletal muscle ryanodine receptor Ca2+ channel and its evaluation as a test substance for the assessment of susceptibility to malignant hyperthermia
BMC Pharmacology volume 9, Article number: A22 (2009)
3,5-Di-t-butyl catechol (DTCAT) has been shown to release Ca2+ from rat skeletal muscle sarcoplasmic reticulum (SR) vesicles, which makes it a possible candidate for use as a substitute for halothane or caffeine in the in vitro contracture test (IVCT) for the assessment of susceptibility to malignant hyperthermia (MHS).
To characterize the effect of DTCAT at the cellular level, Ca2+ release experiments were performed on cultured, human skeletal muscle cells using the fluorescent Ca2+ indicator fura2-AM. DTCAT was also used for the first time in the IVCT to induce contractures in human skeletal muscle bundles obtained from individuals diagnosed susceptible (MHS), normal (MHN) or equivocal (MHE); these effects were compared to those elicited by the standard test substances caffeine and halothane.
In single cultured skeletal muscle cells, DTCAT released Ca2+ from intracellular stores with a higher potency when compared to caffeine. This effect, however, was unspecific, since the release of Ca2+ from stores other than the SR was evident, as well as a Ca2+ influx, possibly triggered by depletion of intracellular Ca2+ stores. DTCAT induced contractures in skeletal muscle bundles in a concentration-dependent manner with an EC50 value of 160 ± 91 μM. However, the reaction to DTCAT in muscles from MHS individuals was similar to reactions to DTCAT in MHE or MHN muscles.
Due to its low specificity in inducing the release of Ca2+ from SR stores and the additional activation of Ca2+ influx, DTCAT is not an appropriate test substance for the diagnosis of MH.
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Lacava, C., Michalek-Sauberer, A., Kraft, B. et al. 3,5-Di-t-butyl catechol (DTCAT) as an activator of the human skeletal muscle ryanodine receptor Ca2+ channel and its evaluation as a test substance for the assessment of susceptibility to malignant hyperthermia. BMC Pharmacol 9 (Suppl 2), A22 (2009). https://doi.org/10.1186/1471-2210-9-S2-A22