Brain electrobiogenesis protection induced by nimodipine and MK-801 during acute hypoxia in hypertensive rats.

The protective effect of nimodipine, a calcium entry blocker, and MK-801, an excitatory amino acid antagonist, on the cortical electrobiogenesis of hypertensive SHR-Charles-River adult rats during a 90-s session of acute hypoxia, was tested either with a single treatment or with a therapeutic association. Pretreatment with nimodipine alone (0.1 mg kg-1, i.v.) was particularly effective in increasing the rat brain resistence to hypoxia when compared to the controls. MK-801 pretreatment alone (3 mg kg-1, subcutaneous), improved significantly the recovery of brain electrical activity from hypoxia, as it not only shortened the recovery time but also abolished the post-hypoxic burst activity. The combined pretreatment with both drugs, using the same doses, displayed a more powerful brain protective effect on the cortical electrobiogenesis than the single drug pretreatment, suggesting the existence of a synergy between nimodipine and MK-801.