Nifedipine. L-type Cav Channel Blocker.
Native voltage-gated Ca2+ channels (VGCC, Cav) are pharmacologically classified into at least five different subclasses (L-, N-, P-, Q-, and R-type), the characteristics of which are determined by the pore- forming alpha1 subunit. The subunits Cav1.1-1.4 (alpha1S, alpha1C, alpha1D and alpha1F) form L-type Ca2+ channels and bind dihydropyridines (DHPs) with high affinity.
Nifedipine, a DHP, is a selective L-type Ca2+ channel blocker.
10 μM Nifedipine inhibits ~65% of the L-type channel current at a holding potential of -80 mV, in Xenopus oocytes.
Nifedipine was initially developed for the prophylaxis of angina symptoms, and then later used as an anti-hypertensive agent. Nifedipine acts by inhibiting the transmembrane influx of calcium into cardiac and vascular smooth muscle cells, thus reducing muscle contraction and has predominantly vasodilatory effects on arteries with minimal effects on the myocardium and cardiac conduction.�For the same reason Nifedipine is also useful in the reduction of the frequency and severity of the attacks in Raynaud�s phenomenon, an episodic vasospasm of the peripheral arteries.
Uterine contractions are the most frequently recognized symptom and sign of preterm labor and hence, inhibition of uterine contractility with tocolytic agents to prolong pregnancy and reduce neonatal complications continues to be the focus of treatment of preterm labor. The efficacy and safety of Nifedipine as a tocolytic agent in women with preterm labor were determined and provide another indication for Nifedipine.
Ion Channel Modulators; Voltage - Gated Ca2+ Channel Blockers.