巢蛋白阳性星形胶质细胞与癫痫持续状态后海马区胶质瘢痕形成的相关性研究

目的 了解癩痫持续状态(SE)后7d海马各区巢蛋白(nestin)阳性星形胶质细胞表达及数目的变化,探讨其与SE导致海马区胶质瘢痕形成的关系.方法 SD大鼠随机分为SE组和对照组,应用匹罗卡品建立SE大鼠模型;在SE后7d处死大鼠行盲法免疫荧光组化实验,观察大鼠海马各区nestin与胶质纤维酸性蛋白单克隆抗体(GFAP...     

醒脑静注射液辅助静脉用丙戊酸钠治疗癫(癎)持续状态效果观察

目的:探讨醒脑静注射液配合丙戊酸钠治疗癫(癎)持续状态的疗效.方法:选择我院2013年8月～2016年1月收治的癫(癎)持续状态患者74例为研究对象,以随机数字表法分组,观察组37例,对照组37例,对照组单用丙戊酸钠治疗,观察组采取醒脑静注射液辅助静脉用丙戊酸钠治疗,对两组患者疗效进行观察.结果:观察组总有效率为92％,对照组为81％,两组比较差异有统计学意义(P＜0.05);观察组起效时间及完全控制时间均较对照组短,两组比较差异有统计学意义(P＜0.05);观察组复发率与不良反应发生率分别为8％和11％,对照组分别为11％和21％,两组比较差异均有统计学意义(P＜0.05).结论:醒脑静注射液辅助静脉用丙戊酸钠治疗癫(癎)持续状态效果显著,此两药具有相互协同作用,可快速起效,安全性高,利于远期预后.     

Development of pharmacoresistance to benzodiazepines but not cannabinoids in the hippocampal neuronal culture model of status epilepticus

Status epilepticus (SE) is a life-threatening neurological disorder associated with a significant morbidity and mortality. Benzodiazepines are the initial drugs of choice for the treatment of SE. Despite aggressive treatment, over 40% of SE cases are refractory to the initial treatment with two or more medications. It would be a major advance in the clinical management of SE to identify novel anticonvulsant agents that do not lose their ability to treat SE with increasing seizure duration. Cannabinoids have recently been demonstrated to regulate seizure activity in brain. However, it remains to be seen whether they develop pharmacoresistance upon prolonged SE. In this study, we used low Mg(2+) to induce SE in hippocampal neuronal cultures and in agreement with animal models and human SE confirm the development of resistance to benzodiazepine with increasing durations of SE. Thus, lorazepam (1 microM) was effective in blocking low Mg(2+) induced high-frequency spiking for up to 30 min into SE. However, by 1 h and 2 h of SE onset it was only 10-15% effective in suppressing SE. In contrast, the cannabinoid type-1 (CB1) receptor agonist, WIN 55,212-2 (1 microM) in a CB1 receptor-dependent manner completely abolished SE at all the time points tested even out to 2 h after SE onset, a condition where resistance developed to lorazepam. Thus, the use of cannabinoids in the treatment of SE may offer a unique approach to controlling SE without the development of pharmacoresistance observed with conventional treatments.     

Propofol effectively inhibits lithium-pilocarpine-induced status epilepticus in rats via downregulation of N-methyl-D-aspartate receptor 2B subunit expression

Status epilepticus was induced via intraperitoneal injection of lithium-pilocarpine.The inhibitory effects of propofol on status epilepticus in rats were judged based on observation of behavior,electroencephalography and 24-hour survival rate.Propofol(12.5-100 mg/kg) improved status epilepticus in a dose-dependent manner,and significantly reduced the number of deaths within 24 hours of lithium-pilocarpine injection.Western blot results showed that,24 hours after induction of status epilepticus,the levels of N-methyl-D-aspartate receptor 2A and 2B subunits were significantly increased in rat cerebral cortex and hippocampus.Propofol at 50 mg/kg significantly suppressed the increase in N-methyl-D-aspartate receptor 2B subunit levels,but not the increase in N-methyl-D-aspartate receptor 2A subunit levels.The results suggest that propofol can effectively inhibit status epilepticus induced by lithium-pilocarpine.This effect may be associated with downregulation of N-methyl-D-aspartate receptor 2B subunit expression after seizures.     

锂-匹罗卡品诱导癫痫持续状态大鼠海马CA1，CA3和PG区P糖蛋白的动态表达

【背景】药物抗性癫痫的病理生理机制目前还不清楚。现有的证据提示P糖蛋白可能参与了药物抗性癫痫的形成。【目的】观察锂-匹罗卡品诱导的大鼠慢性颞叶内侧癫痫模型中海马不同分区P糖蛋白是否出现过度表达,并进而探讨其表达与癫痫发作频度是否相关。【方法】选择6-8周雌性SD大鼠,予锂-匹罗卡品诱导大鼠形成颞叶内侧癫痫慢性模型,对大鼠进行行为学观察及视频脑电记录;Western-Blot、实时定量RT-PCR及免疫组化方法分别检测P糖蛋白在处理组、假处理组、空白对照组中不同时间点（1d及60d）海马不同分区（CA1、CA3及DG）的表达情况。【结果】87.5％（35/40）的大鼠在锂-匹罗卡品诱导的急性期出现惊厥持续状态,伴有与临床癫痫全身发作类似的脑电变化;慢性期出现自主发作,发作间期脑电记录可见到痫性放电;与对照组相比,模型鼠急性期及慢性期在海马CA1、CA3及DG区均出现P糖蛋白的过度表达,增加约70％以上(p<0.05);应用免疫组化染色发现P糖蛋白阳性显色定位于锥体细胞层神经元上。【结论】在慢性颞叶内侧癫痫模型中急性期及慢性期海马锥体细胞层神经元均出现P糖蛋白的过度表达,并证实P糖蛋白的过度表达可能与痫性发作密切相关,但非发现其表达程度与发作频度相关。     

Effects of 6-month at-home transcranial direct current stimulation on cognition and cerebral glucose metabolism in Alzheimer's disease

BackgroundAlthough single or multiple sessions of transcranial direct current stimulation (tDCS) on the prefrontal cortex over a few weeks improved cognition in patients with Alzheimer's disease (AD), effects of repeated tDCS over longer period and underlying neural correlates remain to be elucidated.ObjectiveThis study investigated changes in cognitive performances and regional cerebral metabolic rate for glucose (rCMRglc) after administration of prefrontal tDCS over 6 months in early AD patients.MethodsPatients with early AD were randomized to receive either active (n = 11) or sham tDCS (n = 7) over the dorsolateral prefrontal cortex (DLPFC) at home every day for 6 months (anode F3/cathode F4, 2 mA for 30 min). All patients underwent neuropsychological tests and brain ¹⁸F-fluoro-2-deoxyglucose positron emission tomography (FDG-PET) scans at baseline and 6-month follow-up. Changes in cognitive performances and rCMRglc were compared between the two groups.ResultsCompared to sham tDCS, active tDCS improved global cognition measured with Mini-Mental State Examination (p for interaction = 0.02) and language function assessed by Boston Naming Test (p for interaction = 0.04), but not delayed recall performance. In addition, active tDCS prevented decreases in executive function at a marginal level (p for interaction < 0.10). rCMRglc in the left middle/inferior temporal gyrus was preserved in the active group, but decreased in the sham group (p for interaction < 0.001).ConclusionsDaily tDCS over the DLPFC for 6 months may improve or stabilize cognition and rCMRglc in AD patients, suggesting the therapeutic potential of repeated at-home tDCS.     

Nerve growth factor and choline acetyltransferase activity levels in the rat brain following experimental impairment of cerebral glucose and energy metabolism.

Intracerebroventricular (ICV) injection of streptozotocin (STZ) has been reported to impair cerebral glucose utilization and energy metabolism (Nitsch and Hoyer: Neurosci Lett, 128:199-202, 1991) and also to prejudice passive avoidance learning in adult rats (Mayer et al.: Brain Res 532:95-100, 1990). It is well established that the forebrain cholinergic system, whose integrity is essential for learning and memory functions, depends on the target-derived retrograde messenger nerve growth factor (NGF). Therefore, we measured NGF and choline acetyltransferase (ChAT) activity levels in the forebrain cholinergic system in adult rats that had received a single injection of either STZ or artificial cerebrospinal fluid into the left ventricle 1 or 3 weeks prior to sacrifice. One week after ICV STZ treatment, NGF content was significantly decreased (-32%) in the septal region, where NGF-responsive cell bodies are located and NGF exerts its neurotrophic action after retrograde transport from NGF-producing targets. In contrast, NGF levels in the cortex and hippocampus, which are target regions for the basal forebrain cholinergic neurons, and in the brainstem and cerebellum were increased (+12% to +47%) within 3 weeks after ICV STZ treatment. The alterations in NGF levels were not related to changes in ChAT activity that decreased in the hippocampus by only 15%. This might be due to masking effects exerted by compensatory NGF-mediated stimulation of ChAT activity in remaining functional neurons. It is suggested that impaired behavior which has been observed after STZ-induced impairment of cerebral glucose and energy metabolism may be at least partially related to a diminished capacity of central NGF-responsive neurons to bind and/or transport NGF.(ABSTRACT TRUNCATED AT 250 WORDS)     

The 45 kDa form of glucose transporter 1 (GLUT1) is localized in oligodendrocyte and astrocyte but not in microglia in the rat brain

We and others have previously reported that glucose transporter 1 (GLUT1)-like 45 kDa protein is localized to parenchymal cells in the brain. However, the precise cellular localization has remained unclear. In the present study, we examined the cellular localization of GLUT1 in the rat brain by double immunostaining methods and immunoelectron microscopic analysis using a rabbit antiserum specific to GLUT1. Western blot analysis of the rat brain revealed that the antiserum detected a strong band with a molecular weight of 45 kDa and a weak band of about 55 kDa, which corresponded respectively to the known molecular weights of the GLUT1 proteins in the brain parenchymal cells and the brain microvessels. Immunohistochemical staining revealed a large number of GLUT1-immunoreactive glial cells and microvessels in almost every region of the brain. Double immunofluorescence analysis demonstrated that the GLUT1-like 45 kDa protein occurred in many galactocerebroside-positive oligodendrocytes and in some glial fibrillary acidic protein (GFAP)-positive astrocytes. No GLUT1-immunoreactivity was observed in OX42-positive microglia. Immunoelectron microscopic examination confirmed that the GLUT1-immunoreactivity was mainly localized in the cytoplasm of the oligodendrocytes and astrocytes. The results indicate that the 45 kDa form of GLUT1 protein exists in the glial cells including astrocytes and oligodendrocytes.     

Seizure susceptibility and the brain regional sensitivity to oxidative stress in male and female rats in the lithium-pilocarpine model of temporal lobe epilepsy

Several studies have shown the existence of sex differences in the sensitivity to various convulsants in animals and to the development of some epilepsy types in humans. The purpose of this study was to investigate whether there are sex differences in seizure susceptibility and sensitivity of different brain regions to oxidative stress in rats with status epilepticus (SE) induced by lithium-pilocarpine administration, that provides a common experimental model of temporal lobe epilepsy (TLE) in humans.     

The effects of tifluadom and ketazocine on behaviour, dopamine turnover in the basal ganglia and local cerebral glucose utilization of rats

The purpose of the present study was to evaluate the interrelation between behavioural effects of kappa-opiates and cerebral neurochemical correlates in rats. Administration of the kappa-opiates tifluadom (2.5 mg/kg i.p.) or ketazocine (5 mg/kg i.p.) caused a marked initial decrease in locomotor activity lasting about 15-20 min, followed by an increase in locomotor activity at about 40 min after drug administration. At 15 min after i.p. injections of the same drugs 3,4-dihydroxyphenylacetic acid concentrations, measured by HPLC, were slightly increased in the nucleus accumbens, but unchanged in the striatum; dopamine concentrations were unchanged in both regions. The rates of glucose utilization, determined by quantitative [14C]2-deoxyglucose autoradiography, were mainly unchanged except for the nucleus accumbens, which showed an increased glucose utilization after both drugs given i.v. Tifluadom also decreased rates of glucose utilization in the caudate nucleus and parietal, sensorimotor, olfactory and frontal cortices. The above-mentioned effects on behaviour and local cerebral glucose utilization could be prevented by naloxone (3 mg/kg). The data suggest that changes in locomotor activity, neurotransmitter metabolism and neuronal activity in the nucleus accumbens are interrelated and that opiate-induced akinesia is mediated via the nucleus accumbens.     

Structural and functional neuroimaging studies of the suicidal brain

Suicidality is a major challenge for today's health care. Evidence suggests that there are differences in cognitive functioning of suicidal patients but the knowledge about the underlying neurobiology is limited. Brain imaging offers the advantage of a non-invasive in vivo direct estimation of detailed brain structure, regional brain functioning and estimation of molecular processes in the brain.We have reviewed the literature on neuroimaging studies of the suicidal brain. This article contains studies on structural imaging such as Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) and functional imaging, consisting of Positron Emission Tomography (PET), Single Photon Emission Tomography (SPECT) and functional MRI (fMRI). We classified the results of the different imaging modalities in structural and functional imaging.Within our research, we found no significant differences in the suicidal brain demonstrated by Computed Tomography. Magnetic Resonance Imaging studies in subjects with a history of suicide attempt on the other hand deliver differing results, mostly pointing at a higher prevalence of white (especially deep white matter and periventricular) and grey matter hyperintensities in the frontal, temporal and/or parietal lobe and decreased volumes in the frontal and temporal lobe. There seems to be a trend towards findings of reduced grey matter volume in the frontal lobe. Overall, there is no consensus of opinion on structural imaging of the suicidal brain.Research on functional imaging is further divided into studies in resting state, studies in activation conditions and studies on brain neurotransmitters, transporters and receptors.A common finding in functional neuroimaging in resting conditions is a decreased perfusion in the prefrontal cortex of suicidal patients. During cognitive activation, perfusion deficits in the prefrontal cortex have been observed. After fenfluramine challenge, the prefrontal cortex metabolism seems to be inversely correlated to the lethality of previous suicide attempt.The few studies that examined the serotonin transporter in suicide found no significant differences in binding potential. In suicide attempters there seems to be a negative correlation between impulsivity and SERT binding. Our group found a reduced 5-HT_2A binding in the frontal cortex in patients with a recent suicide attempt. The binding index was significantly lower in the deliberate self injury patients compared to the deliberate self poisoning patients.The few authors that examined DAT binding in suicide found no significant DAT differences between patients and controls. However they demonstrated significant negative correlations between DAT binding potential and mental energy among suicide attempters, but not in healthy control subjects. We did not find studies measuring the binding potential of the noradrenalin or gamma amino butyric acid transporter or receptor in suicidal subjects. Several reports have suggested abnormalities of GABA neurotransmission in depression.During our literature search, we have focused on neuroimaging studies in suicidal populations, but in the absence of evidence in the literature on this group or when further collateral evidence is appropriate, this overview expands to results in impulsive aggressive or in depressed subjects.     

Lithium,but not valproate,induces the serine/threonine phosphatase activity of protein phosphatase 2A in the rat brain,without affecting its expression

Summary. Protein phosphatase 2A (PP2A) regulates protein kinase cascades and thus plays an important role in the regulation of cell growth, gene expression and development. We examined the influence of lithium and valproate on the expression of PP2A and its serine/threonine phosphatase activity in the rat frontal cortex and hippocampus. Western blot and immunohistochemical analyses demonstrated that neither lithium nor valproate treatment had an effect on the levels of PP2A immunoreactivity in these brain regions. However, administration of lithium for 1 or 14 days significantly upregulated the activity of PP2A in the frontal cortex. Similarly, lithium administration tended to increase the activity of PP2A in the hippocampus. In contrast, neither a single nor repeated administration of valproate affected the activity of PP2A in these brain regions. These findings indicate that lithium, but not valproate, upregulated the activity of PP2A in the rat brain. It is suggested that the changes in neuronal functions induced by PP2A may be, at least in part, associated with the therapeutic action of lithium. Received September 9, 2002; accepted October 22, 2002 Published online December 16, 2002 Acknowledgements We thank Dr. J. Takahashi (Department of Psychiatry, Shiga University of Medical Sciences), Dr. M. Endo and Ms S. Endo (Department of Pharmacology, Yamagata University, School of Medicine), and Dr. T. Fukumoto and Ms M. Okamura (Department of Psychiatry and Neurosciences, Graduate School of Biomedical Sciences, Hiroshima University) for their help throughout this study. Authors' address: S. Yamawaki, M.D., Ph.D., Department of Psychiatry and Neurosciences, Division of Frontier Medical Science, Programs for Biomedical Research, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan, e-mail: yamawaki@hiroshima-u.ac.jp     

Beneficial effects of sodium or ethyl pyruvate after traumatic brain injury in the rat

Sodium pyruvate (SP) treatment initiated within 5 min post-injury is neuroprotective in a rat model of unilateral cortical contusion injury (CCI). The current studies examined: (1) effects of delayed SP treatments (1000 mg/kg, i.p., at 1, 12 and 24 h), (2) effects of single (1 h) or multiple (1, 12 and 24 h) ethyl pyruvate treatments (EP; at 20 or 40 mg/kg, i.p.), and (3) mechanisms of action for pyruvate effects after CCI. In Experiment 1, both SP and EP treatment(s) significantly reduced the number of dead/dying cells in the ipsilateral hippocampus (dentate hilus + CA3_c and/or CA3_a-b regions) at 72 h post-CCI. Pyruvate treatment(s) attenuated CCI-induced reductions of cerebral cytochrome oxidase activity at 72 h, significantly improving activity in peri-contusional cortex after multiple SP or EP treatments. Optical density measures of ipsilateral CD11b immuno-staining were significantly increased 72 h post-CCI, but these measures of microglia activation were not different from sham injury values in SP and EP groups with three post-CCI treatments. In Experiment 2, three treatments (1, 12 and 24 h) of SP (1000 mg/kg) or EP (40 mg/kg) significantly improved recovery of beam-walking and neurological scores in the first 3 weeks after CCI, and EP treatments significantly improved spatial working memory 1 week post-CCI. Ipsilateral CA3_b neuronal loss, but not cortical tissue loss, was significantly reduced 1 month post-CCI with pyruvate treatments begun 1 h post-CCI. Thus, delayed pyruvate treatments after CCI are neuroprotective and improve neurobehavioral recovery; these effects may be mediated by improved metabolism and reduced inflammation.     

Estrogen: A master regulator of bioenergetic systems in the brain and body

Estrogen is a fundamental regulator of the metabolic system of the female brain and body. Within the brain, estrogen regulates glucose transport, aerobic glycolysis, and mitochondrial function to generate ATP. In the body, estrogen protects against adiposity, insulin resistance, and type II diabetes, and regulates energy intake and expenditure. During menopause, decline in circulating estrogen is coincident with decline in brain bioenergetics and shift towards a metabolically compromised phenotype. Compensatory bioenergetic adaptations, or lack thereof, to estrogen loss could determine risk of late-onset Alzheimer’s disease. Estrogen coordinates brain and body metabolism, such that peripheral metabolic state can indicate bioenergetic status of the brain. By generating biomarker profiles that encompass peripheral metabolic changes occurring with menopause, individual risk profiles for decreased brain bioenergetics and cognitive decline can be created. Biomarker profiles could identify women at risk while also serving as indicators of efficacy of hormone therapy or other preventative interventions.     

Clinical and advanced neurophysiology in the prognostic and diagnostic evaluation of disorders of consciousness: review of an IFCN-endorsed expert group

The analysis of spontaneous EEG activity and evoked potentials is a cornerstone of the instrumental evaluation of patients with disorders of consciousness (DoC). The past few years have witnessed an unprecedented surge in EEG-related research applied to the prediction and detection of recovery of consciousness after severe brain injury, opening up the prospect that new concepts and tools may be available at the bedside. This paper provides a comprehensive, critical overview of both consolidated and investigational electrophysiological techniques for the prognostic and diagnostic assessment of DoC. We describe conventional clinical EEG approaches, then focus on evoked and event-related potentials, and finally we analyze the potential of novel research findings. In doing so, we (i) draw a distinction between acute, prolonged and chronic phases of DoC, (ii) attempt to relate both clinical and research findings to the underlying neuronal processes and (iii) discuss technical and conceptual caveats. The primary aim of this narrative review is to bridge the gap between standard and emerging electrophysiological measures for the detection and prediction of recovery of consciousness. The ultimate scope is to provide a reference and common ground for academic researchers active in the field of neurophysiology and clinicians engaged in intensive care unit and rehabilitation.