Category: membrane
L-type Cav1.x channels carry inward Ca²⁺ in cardiac + vascular smooth muscle (phase 2 plateau + vasoconstriction). Dihydropyridines (amlodipine, nifedipine, felodipine, nicardipine, isradipine, nimodipine) preferentially block vascular L-type → vasodilation; reflex tachycardia tempered by long-acting kinetics. Non-dihydropyridines (verapamil phenylalkylamine + diltiazem benzothiazepine) hit cardiac + vascular L-type → AV block + negative inotropy + vasodilation; antiarrhythmic class IV. T-type Cav3.x (ethosuximide) underlies thalamic 3-Hz spike-wave absence seizures. α2δ subunits (gabapentin / pregabalin) modulate channel assembly; gabapentinoids reduce neurotransmitter release at presynaptic terminals.