prostaglandin-b1 and Brain-Ischemia

Topics: Animals; Brain Ischemia; Calcium; Dogs; Haplorhini; Humans; Hypoxia; Molecular Structure; Oxidative Phosphorylation; Polymers; Prostaglandins B; Prostaglandins, Synthetic; Rabbits; Signal Transduction; Structure-Activity Relationship

By using the spin-trapping technique and electron spin resonance spectroscopy (ESR), we detected directly oxygen-derived free radicals in the brain exposed to ischemia and reperfusion. Forebrain ischemia was produced in the rat by bilateral occlusion of the common carotid arteries combined with hemorrhagic hypotension. The whole cerebral cortex was homogenized in the presence of the spin trap agent, N-tert-butyl-alpha-phenylnitrone, followed by a Folch extract. Spin-adducts were detected using ESR. As the index of tissue injury, the lipid peroxidation was estimated from both the amount of thiobarbituric acid reactive substance and the formation of conjugated diene. After 10 or 20 min of ischemia, reperfusion induced a burst of spin adduct formation which peaked at 5 min reperfusion time. The peak value increased with the ischemia time. The degree of lipid peroxidation, which was measured after 20 min of reperfusion, also increased with the ischemia time. When the oligomeric derivative was administered (9 mg . kg-1, i.p.) 30 min before ischemic insult, both spin adduct formation and lipid peroxidation were reduced. The results support the current view that free radicals produced upon reperfusion may be the direct cause of the subsequent lipid peroxidation.

Topics: Animals; Antioxidants; Brain; Brain Ischemia; Electron Spin Resonance Spectroscopy; Free Radicals; Male; Polymers; Prostaglandins B; Rats; Rats, Inbred Strains; Reperfusion Injury

Administration of polymeric prostaglandin PGBx to rabbits after a 20-minute period of almost total obstruction of blood flow to the brain resulted in marked improvement of recovery from brain damage as measured by recovery of brain function. This beneficial effect of PGBx on recovery from acute ischemic tissue damage, analogous to that observed in cardiac tissue of monkeys, may be due to the positive effect of PGBx on phosphorylation in damaged mitochondria as observed previously in vitro. A convenient surgical technique for producing reversible cerebral ischemia in rabbits was developed for and used in this pharmacological study.

Topics: Animals; Brain; Brain Ischemia; Drug Evaluation, Preclinical; Female; Injections, Intravenous; Male; Polymers; Probability; Prostaglandins; Prostaglandins B; Rabbits; Time Factors