Sodium-calcium exchanger 1 (NCX1) (NCX1)

The Sodium-calcium exchanger 1 (NCX1) is a critical electrogenic transporter located on the plasma membrane of sinoatrial node (SAN) cells, where it plays a pivotal role in cardiac pacemaking (UniProt P32418; PubMed 15618538). It functions by exchanging three extracellular sodium ions for one intracellular calcium ion, or vice versa, depending on the electrochemical gradient (UniProt P32418). In the context of the SAN, NCX1 is the primary link between the calcium clock and the membrane clock, as it generates an inward depolarizing current (INCX) in response to spontaneous diastolic calcium releases from the sarcoplasmic reticulum (PubMed 21685500). This current accelerates the late phase of diastolic depolarization, ensuring the timely firing of action potentials that dictate the heart rate (PubMed 15618538; StatPearls NBK541011). Dysregulation of NCX1 activity is associated with various cardiovascular conditions, including sinus node dysfunction, atrial fibrillation, and heart failure (PubMed 21685500). While no NCX-specific inhibitors are currently in widespread clinical use, experimental compounds like SEA0400 and KB-R7943 are being studied for their potential to treat arrhythmias by modulating calcium handling (PubChem CID 119541). Additionally, drugs like digoxin indirectly influence NCX1 activity by altering the sodium gradient across the cell membrane (StatPearls NBK556025).

Other names

SLC8A1Solute carrier family 8 member 1Na+/Ca2+ exchanger 1Sodium/calcium exchanger 1NCX

Inhibition of the sodium-calcium exchange process to modulate intracellular calcium concentrations and the resulting electrogenic current.