L-type voltage-gated calcium channel (LTCC) (LTCC)

L-type voltage-gated calcium channels (LTCCs) are essential multi-subunit protein complexes that mediate the entry of calcium ions into excitable cells in response to membrane depolarization [PubMed: 29033151]. These channels are characterized by their high-voltage activation threshold and long-lasting (L-type) conductance, which distinguishes them from other calcium channel types. The channel complex consists of a pore-forming alpha-1 subunit (Cav1.1, Cav1.2, Cav1.3, or Cav1.4) and several auxiliary subunits (beta, alpha-2-delta, and gamma) that modulate its biophysical properties and cellular localization [UniProt: Q13936]. In the cardiovascular system, LTCCs are fundamental to excitation-contraction coupling in the heart and vascular smooth muscle, as well as the pacemaker activity of the sinoatrial node [StatPearls: NBK482474]. Mutations in the genes encoding these subunits are linked to a variety of channelopathies, including Timothy syndrome, Brugada syndrome, and hypokalemic periodic paralysis [PubMed: 15791251]. Pharmacologically, LTCCs are the primary targets for calcium channel blockers, a major class of drugs used to treat hypertension, angina, and certain arrhythmias by inducing vasodilation and reducing cardiac workload [PubMed: 25324461].

Other names

Voltage-dependent L-type calcium channelCav1 familyDihydropyridine receptorDHPRCalcium channel, voltage-dependent, L typeCACNA1SCACNA1CCACNA1DCACNA1F

L-type calcium channel blockers (CCBs) bind to specific sites on the alpha-1 subunit of the channel, stabilizing it in an inactive or closed state. This inhibition prevents the influx of extracellular calcium ions into the cytosol during membrane depolarization, leading to reduced intracellular calcium concentrations. In vascular smooth muscle, this results in vasodilation and decreased peripheral resistance; in cardiac myocytes, it leads to decreased contractility (negative inotropy) and slowed conduction through the atrioventricular node (negative dromotropy) [StatPearls: NBK482474, PubMed: 29033151].