Brain research
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Comparative Study
Serum S100B indicates brain edema formation and predicts long-term neurological outcomes in rat transient middle cerebral artery occlusion model.
To assess the usefulness of serum S100B as a biomarker, the present study proceeded by observing serum S100B kinetics in a rat transient middle cerebral artery occlusion (MCAO) model, then assessed the correlation between serum S100B and both brain edema formation and neurological outcomes. Study results showed increases in serum S100B concentrations, peaking 48 h after MCAO. Brain water content in the ipsilateral hemisphere significantly increased from 24 h after MCAO, and reached peak value 72 h after MCAO. ⋯ Neurological outcomes were estimated in a long-term study, where a gradual recovery was observed up to 168 h after MCAO. Serum S100B 48 h after MCAO was found to show higher correlation with neurological score 168 h after MCAO than those 48 h after MCAO. These findings suggest that serum S100B is an effective biomarker in predicting both extent of brain edema and long-term neurological outcomes in a rat transient MCAO model.
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Transcutaneous electrical nerve stimulation (TENS) is a commonly utilized non-pharmacological, non-invasive treatment for pain. GABA is a neurotransmitter in the dorsal horn of the spinal cord that mediates analgesia locally, and also through activation of supraspinal sites. TENS reduces hyperalgesia through activation of receptor-mediated pathways at the level of the spinal cord, and supraspinally. ⋯ The increases in GABA do not occur in response to low frequency TENS, and there are no increases in glycine in response to low or high frequency TENS. However, the reduction in primary hyperalgesia by both high and low frequency TENS is prevented by spinal blockade of GABA(A) receptors with bicuculline. Thus, high frequency TENS increases release of GABA in the deep dorsal horn of the spinal cord, and both high and low frequency TENS reduce primary hyperalgesia by activation of GABA(A) receptors spinally.
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Comparative Study
Cerebral blood flow and BOLD fMRI responses to hypoxia in awake and anesthetized rats.
This study investigated the functional MRI responses to graded hypoxia in awake/restrained and anesthetized animals by measuring cerebral blood flow (CBF) and blood oxygenation (BOLD) changes and estimating changes in cerebral metabolic rate of oxygen (CMRO2). Hypoxia in isoflurane anesthetized rats reduced blood pressure but did not change heart rate and respiration rate. In contrast, hypoxia in awake animals showed compensatory responses by sustaining blood pressure, increasing heart rate and respiration rate. ⋯ CMRO2 estimated using a biophysical BOLD model did not change under mild hypoxia but was reduced under severe hypoxia relative to baseline. These results showed that isoflurane attenuated autonomic responses to hypoxia, hypoxia-induced hypocapnia dominated CBF changes, tissues in awake conditions appeared better oxygenated, and severe hypoxia reduced oxygen metabolism. This study underscored the marked differences in BOLD and CBF MRI responses to hypoxia in vivo between awake and anesthetized conditions and has implications for functional MRI studies of hypoxia in anesthetized animal models.
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The spinal cord is well known to undergo inflammatory reactions in response to traumatic injury. Activation and proliferation of microglial cells, with associated proinflammatory cytokines expression, plays an important role in the secondary damage following spinal cord injury. It is likely that microglial cells are at the center of injury cascade and are targets for treatments of CNS traumatic diseases. ⋯ In the olomoucine-treated group, a significant reduction of activated and/or proliferated microglial induced IL-1beta expression was observed 24 h after SCI. Moreover, olomoucine evidently attenuated the number of apoptotic neurons after SCI. Our findings suggest that modulation of microglial proliferation with associated proinflammatory cytokine expression may be a mechanism of cell cycle inhibition-mediated neuroprotections in the CNS trauma.
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Spinal cord stimulation (SCS), also known as dorsal column stimulation, is a novel technique used widely in pain surgery. However, its effect on other pathologies such as epileptic disorders is unknown. The aim of this study is to evaluate the influence of electrical epidural stimulation of the upper cervical region on epileptic cortical discharges. ⋯ Spinal cord stimulation decreased penicillin-induced median values of epileptic discharges. Epileptic wave frequencies decreased significantly with increasing intensities of SCS. The results of this study suggest that SCS used for drug resistant epilepsies may be a viable alternative treatment modal.