L-type calcium channel (cardiac subtype) (LTCC (sometimes Cav1.2, specifically for the primary cardiac isoform))

The **L-type calcium channel (cardiac subtype, predominantly CaV1.2)** is a high-voltage activated, voltage-gated ion channel complex that mediates the influx of calcium ions into cardiac myocytes during the plateau phase of the cardiac action potential[1][5][7][9]. This calcium influx is the key trigger for excitation-contraction coupling, initiating muscle contraction by inducing further calcium release from intracellular stores[3][5]. These channels are multi-subunit protein complexes composed of a pore-forming α₁ subunit (mostly CaV1.2 in the heart, gene: CACNA1C) and auxiliary subunits[5]. Pharmacological inhibition of these channels by various classes of calcium channel blockers (dihydropyridines, phenylalkylamines such as verapamil, and benzothiazepines such as diltiazem) forms the basis of several widely-used treatments for arrhythmias, hypertension, and angina[1][3][7][9]. Genetic or acquired dysfunction of these channels underlies several inherited or acquired cardiac disorders, including Timothy syndrome, Brugada syndrome, and heart failure[7][9]. The unique properties, pharmacological sensitivity, and pathophysiological relevance of the cardiac L-type calcium channel make it one of the most important ion channel targets in cardiovascular medicine.

Other names

Cardiac L-type calcium channelCardiac voltage-gated calcium channelCaV1.2 (gene: CACNA1C)Dihydropyridine receptor (in cardiac context, refers to the same channel)LTCC (general)Cardiac calcium channel (non-specific, but often used to refer to Cav1.2)

Blockade by calcium channel blockers (e.g., verapamil, diltiazem, dihydropyridines) reduces Ca²⁺ influx, leading to decreased contractility, heart rate, and vasodilation[1][3][7]. Some mutations alter channel gating, affecting pharmacological response[7].