Brain extraction of a calcium channel blocker

Dihydropyridine calcium channel blockers may be effective treatment for acute cerebral ischemia, but the uptake of these drugs into the brain is unknown. A 0.2‐ml bolus of [¹⁴C]nicardipine hydrochloride and [³H] water was injected into the common carotid arteries of 7 normal and 7 ischemic rats. The corrected first‐pass extraction of nicardipine, compared to water, was calculated to be 30.7% into the hemispheres and 42.3% into the hippocampi. The uptake was greater into the ischemic hemispheres (p ≤ 0.001). These data suggest that dihydropyridines are available to binding sites and calcium channels in neurons.