PLN and atrial fibrillation: Compared to control groups, mRNA and protein expressions of LVDCCa1c were significantly decreased; moreover, mRNA and protein expressions of Ca2+-ATPase, RYR2 and IP3R1 were significantly decreased in both adult and aged groups in AF (all P < 0.05), while mRNA and protein expressions of PLN showed a down-regulation tendency, but had no significant difference in two groups (P > 0.05).