[Protective effect of nicardipine hydrochloride on the evolution of delayed neuronal death--an immunohistochemical...

Alteration of evolution of delayed neuronal death in the gerbil after intraperitoneal injection of nicardipine was investigated by using immunohistochemistry for microtubule associated protein (MAP) which enables early detection of ischemic injuries. Male Mongolian gerbils were subjected to intraperitoneal injection of nicardipine at concentrations of 0.01-10 mg/kg and subsequent occlusion of bilateral carotid arteries for 5 min. Extent of the lesions estimated by immunohistochemistry for MAP was reduced at the dosages of 0.2 mg/kg nicardipine as compared with control, while lesser or larger amounts have failed to protect the brain tissue from ischemic insults. Furthermore, pre- and postoperative treatment of 0.2 mg/kg of nicardipine two times daily succeeded to partially attenuate the development of delayed neuronal death in gerbils which underwent ischemia for 5 min and subsequent reperfusion for 4 days. These results indicate that optimal concentration of nicardipine ameliorates delayed neuronal death, presumably because of the increase of cerebral blood flow and intervention of intracellular influx of calcium ions.