Key result
Intracellular flecainide reduces Ca2+ sparks via Na+ channel block rather than direct RyR2 inhibition.
Why the study?
The mechanism of action of flecainide in treating catecholaminergic polymorphic ventricular tachycardia is contentious, particularly regarding its effect on RyR2 channels.
The effect of flecainide on Ca2+ sparks is likely due to Na+ channel block rather than direct action on the cardiac ryanodine receptor.
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No direct RyR2 effect from flecainide in this model; hypothesis-generating for Na+ channel-Ca2+ spark interactions in animals.
Bannister et al. (2016) studied Catecholaminergic polymorphic ventricular tachycardia. Flecainide derivatives (QX-FL and NU-FL) vs. Flecainide was evaluated on Ca(2+) release from the sarcoplasmic reticulum through the ryanodine receptor channel (RyR2) and properties of Ca(2+) sparks. Intracellular flecainide or QX-FL, but not NU-FL, reduced Ca(2+) spark frequency, likely resulting from Na(+) channel block rather than direct action on RyR2 channels.
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