Final answer:
Dihydropyridine calcium channel blockers act by inhibiting the influx of calcium ions through L-type calcium channels in vascular smooth muscle, causing vasodilation, decreased peripheral vascular resistance, and lowered blood pressure.
Step-by-step explanation:
Mechanism of Action of Dihydropyridine Calcium Channel Blockers (CCBs)
The mechanism of action of dihydropyridine calcium channel blockers, such as Amlodipine, Nifedipine, and others, involves the inhibition of calcium influx into cardiac and vascular smooth muscle cells. These medications target the L-type calcium channels, which are predominantly found on the smooth muscle cells of blood vessels, particularly the arterioles. Once bound to these channels, dihydropyridine CCBs cause vasodilation by preventing the entry of calcium ions. This reduced influx of calcium decreases intracellular calcium levels, leading to a decrease in muscle contraction. Consequently, there is a decrease in peripheral vascular resistance, which effectively lowers blood pressure. The selective action of dihydropyridine CCBs on vascular smooth muscle contributes to their effectiveness in treating hypertension and angina by reducing the afterload on the heart and increasing oxygen delivery to the cardiac muscle, respectively.