Resveratrol, a dietary polyphenol with antioxidant and anti-inflammatory activity, has been shown to provide neuroprotection in models of ischemia. However, the mechanism of action of resveratrol-induced neuroprotection remains unclear. Previous work in our laboratory has provided evidence that acute, systemic administration of resveratrol is neuroprotective in a permanent model of cerebral ischemia, an effect that was blocked when animals received the non-selective estrogen receptor antagonist, ICI, 182,780. The present study was designed to investigate whether the source of neuroprotection afforded by resveratrol action within the cerebral cortex itself is mediated preferentially via selective activation of either α or β estrogen receptor subtype. Intracortical injection of resveratrol (0.1 and 1.0 μM) 10 min prior to 30 min of ischemia followed by 5.5h of reperfusion significantly reduced infarct volume in the prefrontal cortex. This neuroprotective effect was significantly attenuated when resveratrol injection (1.0 μM) was preceded by injection of a selective estrogen receptor α antagonist, 1,3-bis(4-hydroxyphenyl)-4-methyl-5-[4-(2-piperidinylethoxy)phenol]-1N-pyrozole dihydrochloride (MPP) or a selective estrogen receptor beta (ERβ) antagonist, 4-[2-phenyo-5,7-bis(trifluoromrthyl)pyrazolo(1,5-a)pyrimidin-3-yl]phenol (PHTPP). These results provide evidence for rapidly induced neuroprotection mediated by resveratrol activation of either estrogen receptor subtype within the ischemic cortex of rats.
Keywords: Ischemia; MPP; PHTPP; Phytoestrogen; Reperfusion.
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