[The effects of post-ischemic delayed hypoperfusion on the process of recovery of brain function]

The author studied the effect of post-ischemic delayed hypoperfusion on the recovery process of brain function after complete cerebral ischemia in a dog model in which the existence of PDH had been shown previously by the author, using nicardipine as a tool to ameliorate the PDH, the effect of the drug also having been demonstrated by the author in the previous study. Twenty-four dogs underwent 15 min complete cerebral ischemia using aortic clamping method with aorto-atrial bypass formation. EEG (for 16 h) and brain functions, awakening, cranial nerve reflexes, motor functions, behaviors and respiratory functions were evaluated using neurological deficit score (NDS) periodically (for 120 h) after ischemia. Eight dogs (1 microgram group) received nicardipine 1 microgram.kg-1.min-1 for 4 h following 10 micrograms bolus iv injection 5 min after declamping of aorta, another 8 dogs (2 micrograms group) received 10 micrograms + 2 micrograms.kg-1.min-1 nicardipine in the same manner as group 1, and the remaining 8 served as controls. In 1 microgram group the first appearance of EEG activities after ischemia was earlier than control group (41 +/- 11 vs 80 +/- 33 min), and also the appearance rate of alpha waves was higher than the controls (87.5% vs 25%) 16 h after declamping of aorta. NDS scores for awakening, behavior, and respiratory functions were better in 1 microgram than the controls between 36 and 48 h post-ischemia, but there were no significant changes in the scores between the two groups 120 h after ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)