Complex sentence: Calcium channel blockers (nimodipine, verapamil which acts as a phenylalkylamine) reduce the calcium influx through L-type calcium channels in smooth muscle cells which leads to vasodilation of arteries which relieves symptoms and can act to prevent vasospasm.
Split into simpler sentences: Calcium channel blockers (nimodipine, verapamil which acts as a phenylalkylamine) reduce the calcium influx through L-type calcium channels in smooth muscle cells. This leads to the vasodilation of arteries, which relieves symptoms and can act to prevent vasospasm.