Molecular Aspects Implicated in Dantrolene Selectivity with Respect to Ryanodine Receptor Isoforms

Area of Science:

• Pharmacology
• Molecular Biology
• Genetics

Background:

• Dantrolene is a skeletal muscle relaxant for malignant hyperthermia (MH).
• MH susceptibility often involves mutations in the skeletal ryanodine receptor (RyR1).
• Dantrolene inhibits RyR1 by reducing aberrant calcium release.

Purpose of the Study:

• To clarify the molecular mechanism of dantrolene's action on ryanodine receptor (RyR) isoforms.
• To identify reasons for contradictory in vitro results regarding dantrolene's effects.
• To propose a role for RyR2 channel phosphorylation in dantrolene sensitivity.

Main Methods:

• Literature review and analysis of in vivo and in vitro studies.
• Comparison of dantrolene-binding sequences across RyR isoforms.
• Interpretation of functional findings within a structural context.

Main Results:

• Dantrolene is an isoform-selective inhibitor, primarily targeting RyR1 and RyR3, not typically RyR2.
• RyR2 channels may become sensitive to dantrolene under specific pathological conditions.
• Conflicting in vitro results may stem from experimental conditions.

Conclusions:

• Phosphorylation of the RyR2 channel is proposed as a mechanism for acquiring dantrolene responsiveness.
• Understanding these mechanisms is crucial for optimizing MH treatment and managing cardiac conditions involving RyR2.
• Further research is needed to reconcile in vivo and in vitro findings and elucidate RyR isoform selectivity.