beta-funaltrexamine and Cerebral-Infarction

Naloxone has been advanced as a potential neuroprotectant against ischemic injury. This study examined the involvement of classical opioid receptors in the reduction of middle cerebral arterial ligation-induced cortical infarction in rats. The infarct volume was significantly reduced after infusion of (-)-naloxone, but not its inert stereoisomer (+)-naloxone. Beta-funaltrexamine (beta-FNA), a mu opioid antagonist, also reduced ischemic infarct volume. Both (-)-naloxone and beta-FNA attenuated cerebral ischemia/reperfusion (I/R)-induced increases in neutrophil-associated myeloperoxidase activity and chemokine mRNA expression, including macrophage inflammatory protein-1 alpha and -2. However, (-)-naloxone and beta-FNA failed to decrease cerebral I/R-induced brain edema. The findings suggest that naloxone, acting through a blockade of mu opioid receptor activation, is beneficial to cerebral I/R insult in terms of reducing brain infarction, neutrophil accumulation, and chemokine expression.

Topics: Animals; Carotid Artery, Common; Cerebral Infarction; Coronary Disease; Functional Laterality; Hypoxia-Ischemia, Brain; Infarction, Middle Cerebral Artery; Male; Naloxone; Naltrexone; Narcotic Antagonists; Rats; Rats, Sprague-Dawley; Receptors, Opioid, mu; Time Factors