Studies on pathophysiology and treatment of cerebral hypoxia with special reference to blood brain barrier

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1. The beneficial effect of methylpredonisolone, urinastatin, vitamin E and coenzyne Q on membrane stability was investigated in rat brains induced by an infusion of hypertonic mannitol solution via the carotid artery.It was found the pretreatment of methylpredonisolone and urinastatin significantly inhibited Evans blue strainly. But no significant difference was observed by vitamin E and coenzyne Q.2. The concentrations of catecolamins and their metabolites (dopamine, HVA, DOPAC, norepinephrine) in striatum was measured during 5% oxygen inhalation and subsequent recovery period in rats, Flunarizine, a calcium channel blocker, was administered and its effect on catecholamine fluctuations was studied. Dopamine increased with 5% oxygen inhalation. DOPAC and norepinephrine decreased and no changes were seen in HVA. After 20 min of hypoxia, catecholamine contents returned to the control levels in another 2 hours of air breathing.When flunarizine was administered before hand. Changes in con … More tent appeared to be lower during hypoxia and subsequent recovery period.3. The morphological changes and calcium accumulation were studied in rat pyramidal nerve cell which had undergone 5% oxygen inhalation and bilateral carotid artery clampings for 15 minutes, using electron and X-ray microanalytical microscopes. To study the protective effects of nicardipine on brain hypoxia, the same techniques were used after hypoxic event. In the 5% oxygen inhalated group, the chromatinclamping in the nucleus was observed, but calcium ions could not be detected in the neuron. In the carotid clamping group under 5% oxygen inhalation, severe nuclear change and mitochondrial swelling were observed and calcium ions were detected in the mitochondrion. After administration of nicardipine under hypoxia and under carotid clamping with hypoxia, similar morphological changes were recognized. It is, therefore, concluded that notable protective effects of nicardipine on ischemic hypoxia were not obtained in this morphological experiment. Less