page_title: L-type calcium channel
hierarchical_section_title: L-type calcium channel
caption_attribution_description: English: A diagram of an L-type calcium channel showing the subunits and some known chemicals that inhibit the channel
context_page_description: The L-type calcium channel is part of the high-voltage activated family of voltage-dependent calcium channel.
  "L" stands for long-lasting referring to the length of activation. This channel has four subunits.
  L-type calcium channels are responsible for the excitation-contraction coupling of skeletal, smooth, cardiac muscle, and for aldosterone secretion in endocrine cells of the adrenal cortex. They are also found in neurons, and with the help of L-type calcium channels in endocrine cells, they regulate neurohormones and neurotransmitters. They have also been seen to play a role in gene expression, mRNA stability, neuronal survival, ischemic-induced axonal injury, synaptic efficacy, and both activation and deactivation of other ion channels.
  In cardiac myocytes, the L-type calcium channel passes inward Ca²⁺ current and triggers calcium release from the sarcoplasmic reticulum by activating ryanodine receptor 2. Phosphorylation of these channels increases their permeability to calcium and increases the contractility of their respective cardiac myocytes.
context_section_description: The L-type calcium channel (also known as the dihydropyridine channel, or DHP channel) is part of the high-voltage activated family of voltage-dependent calcium channel.
  "L" stands for long-lasting referring to the length of activation. This channel has four subunits (Cav1.1, Cav1.2, Cav1.3, Cav1.4).
  L-type calcium channels are responsible for the excitation-contraction coupling of skeletal, smooth, cardiac muscle, and for aldosterone secretion in endocrine cells of the adrenal cortex. They are also found in neurons, and with the help of L-type calcium channels in endocrine cells, they regulate neurohormones and neurotransmitters. They have also been seen to play a role in gene expression, mRNA stability, neuronal survival, ischemic-induced axonal injury, synaptic efficacy, and both activation and deactivation of other ion channels.
  In cardiac myocytes, the L-type calcium channel passes inward Ca²⁺ current and triggers calcium release from the sarcoplasmic reticulum by activating ryanodine receptor 2 (RyR2) (calcium-induced-calcium-release). Phosphorylation of these channels increases their permeability to calcium and increases the contractility of their respective cardiac myocytes.
  L-type calcium channel blocker drugs are used as cardiac antiarrhythmics or antihypertensives, depending on whether the drugs have higher affinity for the heart (the phenylalkylamines, like verapamil), or for the blood vessels (the dihydropyridines, like nifedipine).
  In skeletal muscle, there is a very high concentration of L-type calcium channels, situated in the T-tubules. Muscle depolarization results in large gating currents, but anomalously low calcium flux, which is now explained by the very slow activation of the ionic currents. For this reason, little or no Ca²⁺ passes across the T-tubule membrane during a single action potential.
caption: An L-type calcium channel with its subunits labeled along with some drugs known to inhibit the channel.
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