UC Davis

Ca²⁺ influx through the L-type Ca²⁺ channel Cav1.2 triggers each heartbeat. The fight-or-flight response induces the release of the stress response hormone norepinephrine to stimulate β-adrenergic receptors, cAMP production, and protein kinase A activity to augment Ca²⁺ influx through Ca_v1.2 and, consequently, cardiomyocyte contractility. Emerging evidence shows that Ca_v1.2 is regulated by different mechanisms in cardiomyocytes compared to neurons and vascular smooth muscle cells.