Abstract 14601: TRPC1 Channel Is Upregulated in Atria of Patients With Atrial Fibrillation

Introduction: Our previous study demonstrated that the non-selective cation current mediated by TRPC1 channels is present in human atrial myocytes and activated by endothelian-1 (ET-1). Hypothesis: Regulation of TRPC1 channels by ET-1 is related to activation of intracellular molecular signals and TRPC1 channels are upregulated in atria of patients with persistent atrial fibrillation (AF). Methods: A whole-patch voltage-clamp technique and molecular biological approaches were used to record TRPC1 current and to determine the related gene and protein expression in atrial myocytes and/or tissue specimens of sinus rhythm (SR, n=35) or AF (n=30) patients who underwent cardiac surgery. Results: It was found that ET-1 activated TRPC1 current more in AF myocytes than in SR myocytes (n=10, Pu003c0.05 vs. control). ET-1-evoked TRPC1 current was inhibited by both ETA and ETB receptor antagonists BQ-123 and BQ788 or protein kinase C (PKC) inhibitor chelerythrine. ETA receptor-mediated TRPC1 channel activity was selectiv...