β-Adrenergic and 5-HT4 receptor stimulation exerted similar effects on If in cAF and SR cells, while the ANP-mediated effect was significantly reduced (P < 0.02), suggesting downregulation of natriuretic peptide signaling.
Here, we quantified 5-HT(4) receptors as well as other key genes involved in cardiac rhythm and contraction in right atrial appendages of patients with chronic AF (CAF) and acute AF (AAF).
Our data show that chronic AF is associated with a decrease in the atrial mRNA amount of auxiliary subunits of the L-type Ca2+-channel and of the 5-HT4-receptor.