Brain research bulletin
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Brain research bulletin · Mar 2012
Dexmedetomidine prevents remifentanil-induced postoperative hyperalgesia and decreases spinal tyrosine phosphorylation of N-methyl-d-aspartate receptor 2B subunit.
Numerous studies have demonstrated that prolonged opioid exposure can enhance pain sensitivity that presents as opioid-induced hyperalgesia (OIH). Activation of spinal α2-adrenergic receptor may play an important role in the development of OIH. Dexmedetomidine is an α2-adrenergic agonist that has been shown to synergize with opioids. ⋯ Correlated with the pain behavior changes, Western blotting experiments also revealed that dexmedetomidine could decrease NR2B subunit phosphorylation (Tyr1472 site) in the dorsal horn, which was upregulated after remifentanil infusion. These results suggest that dexmedetomidine can efficiently alleviate OIH and it may be an effective novel option for the treatment of OIH. Our data also provide evidence that dexmedetomidine's anti-hyperalgesic effect may depend on its ability to modulate spinal cord NMDAR activation via suppression of NR2B phosphorylation.
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Brain research bulletin · Mar 2012
Probucol modulates oxidative stress and excitotoxicity in Huntington's disease models in vitro.
Huntington's disease (HD) is an autosomal dominant inherited neurodegenerative disease characterized by symptoms attributable to the death of striatal and cortical neurons. The molecular mechanisms mediating neuronal death in HD seem to be related to oxidative stress, excitotoxicity and misbalance in energetic metabolism. In this study we evaluated the potential relationship between energetic impairment, excitotoxicity and oxidative stress in rat striatal slices exposed to quinolinic acid (QA; as an excitotoxic model), 3-nitropropionic acid (3-NP; as an inhibitor of mitochondrial succinate dehydrogenase), as well as a combined model produced by the co-administration of these two toxins at subtoxic concentrations. ⋯ Our data suggest that the two studied toxic models (QA and 3-NP) or the combined model (QA plus 3-NP) can generate complex patterns of damage, which involve metabolic compromise, ROS formation, and oxidative stress. Moreover, a partial inhibition of SDH by subtoxic 3-NP and moderate excitotoxicty by subtoxic QA are potentiated when both agents are associated. The toxic action of QA plus 3-NP seems to be involved with Ca2+ metabolism and ROS formation, and can be prevented or attenuated by antioxidant/scavenger compounds and NMDAr antagonists.