Brain research
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Oxidative and cytotoxic damage plays an important role in cerebral ischemic pathogenesis and may represent a target for treatment. Curcumin is proved to elicit a vanity of biological effects through its antioxidant and anti-inflammatory properties. But the mechanisms underlying are poorly understood. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) coordinates expression of genes required for free radical scavenging, detoxification of xenobiotics, and maintenance of redox potential. This study evaluated the time course expression regularity of Nrf2, HO-1 and the curcumin's role in cerebral ischemia and its potential mechanism. ⋯ Nrf2 and HO-1 were induced at the early stage after MCAO. Curcumin protected the brain from damage caused by MCAO, this effect may be through upregulation of the transcription factor Nrf2 expression. Nrf2 may be one of the strategic targets for cerebral ischemic therapies.
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Three spatio-temporal neurophysiological patterns involved in visual selective attention were identified from the human event-related potentials (ERPs) by a novel common spatial pattern (CSP) decomposition method and the standardized low resolution brain electromagnetic tomography (sLORETA). In the experiment, stimuli were rapidly presented randomly to the right or left visual fields while subjects attended to one visual field at a time (Clark, Hillyard, 1996. Spatial selective attention affects early extrastriate but not striate components of the visual evoked potential. ⋯ The temporal waveforms indicated that contralateral PFC and PPC were activated synchronously at about 150 ms after the stimulus onset, with early attention effects only occurring in PFC, and the PPC was activated earlier than that of PFC during 200-260 ms. The results imply that humans adopt different allocation strategies for resources in visual attention and un-attention situations. For attention case, visual cortex consumes the most resources and for non-attention situation, the ACC and PPC consume the most resources.
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Activation of the trigeminovascular pain signalling system, including cerebral arteries, meninges, trigeminal ganglion, and brain stem, is involved in migraine. Furthermore, stimulation of cyclic nucleotide (cAMP and cGMP) production as well as inhibition of phosphodiesterases (PDEs) induces headache and migraine. In order to investigate the possible role of PDE in the pain pathway of migraine, expression of the most recently discovered PDE subtypes (9A, 10A and 11A) in cerebral arteries, dura mater, and trigeminal ganglion and nucleus was examined. ⋯ Immunohistochemistry revealed that PDE9A, PDE10A and PDE11A are localised in the cytosol of nerve cell bodies of the trigeminal ganglion. We here present, for the first time, the expression of PDE9A, PDE10A, and PDE11A in the trigeminovascular system. The functional implications are yet unknown, but their localisation indicates that they may have a role in the pain pathway of migraine as well as trigeminal neuralgia and trigeminal autonomic cephalalgias.
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Hypoxia-inducible transcription factors (HIFs) are crucially involved in brain development and cellular adaptation to hypoxia and ischemia. Degradation of HIF is regulated under normoxia by oxygen-dependent hydroxylation of specific prolyl residues on the labile alpha-subunit by HIF prolyl hydroxylases (PHD). Prolyl-4-hydroxylase inhibitors (PHI) have shown protective effects in vitro and in vivo in adult kidney and brain. ⋯ In the brain, HIF-1alpha and HIF-2alpha protein markedly accumulated in response to FG-4497. Besides vasoactive factors, PHI significantly increased cerebral chemokine receptor CXCR-4 mRNA levels. In conclusion, the novel PHI FG-4497 activates HIFs at an early stage of brain maturation and modulates neurotrophic processes known to be crucially involved in brain development and hypoxia-induced brain pathology.
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Novel neurorehabilitative strategies are needed to improve motor outcomes following stroke. Based on the disynaptic excitatory projections of the dentatothalamocortical pathway to the motor cortex as well as to anterior and posterior cortical areas, we hypothesize that chronic electrical stimulation of the contralesional dentate (lateral cerebellar) nucleus output can enhance motor recovery after ischemia via augmentation of perilesional cortical excitability. Seventy-five Wistar rats were pre-trained in the Montoya staircase task and subsequently underwent left cerebral ischemia with the 3-vessel occlusion model. ⋯ There was no difference on the left (ipsilesional) side motor performance among the sham or stimulation groups, varying from 15.9+/-6.7 to 17.2+/-2.1 pellets. We conclude that contralesional chronic electrical stimulation of the lateral cerebellar nucleus at 20 pps but not at 10 or 50 pps improves motor recovery in rats following ischemic strokes. This effect is likely to be mediated by increased perilesional cortical excitability via chronic activation of the dentatothalamocortical pathway.