Brain research
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Traumatic brain injury (TBI) is a leading cause of morbidity in children and boys are disproportionately represented. Hypotension is common and worsens outcome after TBI. Previous studies show that adrenomedullin, a cerebrovasodilator, prevented sex dependent impairment of autoregulation during hypotension after piglet fluid percussion brain injury (FPI). ⋯ SNP aggravated ERK MAPK upregulation after FPI. These data indicate that despite prevention of reductions in CBF after FPI, SNP does not prevent impairment of autoregulation during hypotension after FPI. These data suggest that therapies directed at a purely hemodynamic increase in CPP will fail to improve outcome during combined TBI and hypotension.
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The descending serotonergic (5-HT) system is shown to be plastically altered under pathological conditions such as inflammation or peripheral nerve lesion. Although much evidence indicates that the potentiation of descending facilitatory 5-HT pathways may contribute to the development of chronic pain, the inhibition of descending inhibitory 5-HT system may be functionally more important to the development of central sensitization and neuropathic pain. ⋯ In consistent with these observations, we also found an obvious decrease in the content of 5-HT and 5-HIAA, and a marked increase in the turnover rate of 5-HT (5-HIAA/5-HT) in the ipsilateral dorsal half of the lumbar spinal cord after SNL. These data indicate that a loss or decrease in the descending inhibitory 5-HT system upon the spinal processing of nociceptive information appears to occur following spinal nerve injury, and this kind of decrease in the descending inhibitory 5-HT system is proposed to be involved in the development of central sensitization and ultimately to the nerve injury-induced neuropathic pain.
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The affective priming effect has mostly been studied using reaction time (RT) measures; however, the neural bases of affective priming are not well established. To understand the neural correlates of cross-domain emotional stimuli presented rapidly, we obtained event-related potential (ERP) measures during an affective priming task using short SOA (stimulus onset asynchrony) conditions. Two sets of 480 picture-word pairs were presented at SOAs of either 150ms or 250ms between prime and target stimuli. ⋯ In contrast, late positive potentials (LPPs) (associated with attentional resource allocation) occurred across the scalp at an SOA of 250ms. LPPs were only observed for positive target words at posterior parts of the brain at an SOA of 150ms. Our finding of ERP signatures at very short SOAs provides the first neural evidence that affective pictures can exert an automatic influence on the evaluation of affective target words.
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Audiogenic kindling (AK) represents a model of naturally occurring epileptogenesis in which intensification of repeatedly induced audiogenic seizures results from propagation of epileptic activity from the brainstem to forebrain. Previously it has been shown that unilateral cortical spreading depression (SD) is a reliable earliest manifestation of mild AK produced by repetition of minimal audiogenic seizures (running) in Wistar rats. The unilateral triggering SD suggests the existence of asymmetry in the forebrain recruitment during the kindling and the present study examined whether epileptogenesis produced by this mild AK paradigm is a lateralized process. ⋯ Cortical SD was recorded after repeated running seizures in all rats with reproducible audiogenic response irrespective of the running lateralization and propensity to kindling. Until the late kindling stages, SD was triggered unilaterally in the cortex ipsilateral to the running direction. These findings indicate intrinsically determined lateralization of epileptogenic process in the mild AK model and enhanced vulnerability of the left hemisphere to epileptogenesis.
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The present study was undertaken to investigate the neuroprotective effects of resveratrol (RES) on 6-hydroxydopamine (6-OHDA)-induced Parkinson's disease (PD) in rats. PD is an age-related neurodegenerative disorder in which the role of reactive oxygen species (ROS) is strongly implicated. RES, a polyphenolic antioxidant compound enriched in grapes, has been shown to have antioxidant and anti-inflammatory actions and thus was tested for its beneficial effects using 6-OHDA-induced PD rat model. ⋯ Conversely, the elevated level of thiobarbituric acid reactive substances (TBARS), protein carbonyl (PC), and activity of phospholipase A2 in 6-OHDA group was attenuated significantly in RES-pretreated group when compared with 6-OHDA-lesioned group. These results were supported by the immunohistochemical findings in the substantia nigra that has shown the protection of neurons by RES from deleterious effects of 6-OHDA. Thus, RES may be used to reduce the deterioration caused by free radicals thereby preventing subsequent behavioral, biochemical, and histopathological changes that occur during PD.