L-type calcium channel
Editor-In-Chief: C. Michael Gibson, M.S., M.D. 
The L-type calcium channel is a type of voltage-dependent calcium channel. Like the others of this class, the α1 subunit is the one that determines most of the channel's properties.
L-type calcium channel blockers are used as antiarrhythmics or antihypertensives, depending on whether the drugs has higher affinity to the heart (like verapamil) or to the vessels (nifedipine).
L-type channels are selectively blocked by dihydropyridines.
In skeletal muscle, there is a very high concentration of DHP receptors, representing L-type calcium channels, situated in the T-tubules. Muscle depolarization results in large gating currents, but anomolously low calcium flux, which is now explained by the very slow activation of the ionic currents. For this reason, little or no Ca2þ passes across the T-tubule membrane during a single action potential.
- L-Type+Calcium+Channel at the US National Library of Medicine Medical Subject Headings (MeSH)