Is recovery of cardiac calcium release controlled by sarcoplasmic reticulum refilling and ryanodine receptor sensitivity?
Together, the results strongly suggest that: (i) local SR refilling controls Ca(2+) spark amplitude recovery; (ii) Ca(2+) spark triggering depends on both refilling and RyR sensitivity; and (iii) β-adrenergic stimulation influences both processes.
We conclude that different and even identical PLA2G6 mutations may cause neurodegenerative diseases with heterogeneous clinical manifestations, including INAD, NBIA and dystonia-parkinsonism.