成年大鼠脑创伤后脑组织碱性成纤维细胞生长因子表达的变化

目的:研究液压冲击性脑损伤后成年大鼠脑组织碱性成纤维细胞生长因子(bFGF)表达时程和空间分布的变化。方法:制作液压冲击性脑损伤模型,免疫组织化学法动态检测内源性bFGF的变化。结果:在正常脑组织中,bFGF免疫活性低水平表达,且主要位于胶质细胞核及神经元细胞质中。液压冲击伤后bFGF免疫活性增强,聚集核周边。此外,部分bFGF免疫活性聚集于神经元周围间隙中半定量分析显示液压冲击伤后3d,大脑皮质bFGF阳性细胞数量较正常对照组升高4.8倍;伤后7 d,bFGF免疫活性达高峰,伤后30 d消失。结论:液压冲击伤后,损伤的胶质细胞和神经元暂短地合成bFGF,并以旁分泌和自分泌形式起作用。     

Neuronal GDNF Expression in the Adult Rat Nervous System Identified By In Situ Hybridization

Glial cell line-derived neurotrophic factor (GDNF) is a potent neurotrophic factor which has been purified on the basis of its ability to promote the survival of dopaminergic neurons in vitro. GDNF has subsequently been cloned and its sequence shown to be distantly related to transforming growth factor-β (TGF-β). To identify GDNF expressing cells in the adult rat brain, in situ hybridization using a digoxygenin (DIG)-labelled riboprobe has been performed. Our results show that GDNF mRNA is mainly expressed in neurons and that its synthesis is not restricted to dopaminergic areas. It is widely expressed in the cortex, the hippocampus, the striatum, the substantia nigra, the thalamus, the cerebellum and the spinal cord. Neuronal GDNF expression varies among brain regions as determined by the intensity of the in situ signal. Double labelling of the substantia nigra using tyrosine hydroxylase immunohistochemistry, associated with GDNF in situ hybridization, show that the majority of dopaminergic neurons express GDNF. The widespread expression of GDNF throughout the adult brain suggests that its administration in Parkinson's disease should be restricted to the altered structures, in order to avoid possible deleterious side effects.     

Proteomic Analysis of Lithium-Induced Gene Expression in the Rat Hypothalamus

The hypothalamic proteomes were analyzed 1 and 6 hr after an intraperitoneal injection of lithium chloride or sodium chloride (0.15 M, 12 ml/kg). Results showed that expression of 14 and 32 proteomes was increased consistently by 1 hr and 6 hr of lithium treatment, respectively. Among them, tentative implications of glial fibrillary acidic protein, receptor-type protein tyrosine phosphatase, spectrin, and glutamate dehydrogenase in the lithium-induced activation of the hypothalamic-pituitary-adrenal axis, and conditioned taste aversion have been discussed. The proteomes listed in this study will provide, at least, a new insight to understand the molecular mechanism of lithium's action in the brain.     

Thyroid Hormone-Induced Plasticity in the Adult Rat Brain

It is well known that thyroid hormone plays a crucial role in the development and maturation of the nervous system. However, little is known about the role of thyroid hormone in the adult brain. In this short review we have dwelt on this point, with regard to the role of thyroid hormone on neuropeptide gene expression regulation in the paraventricular nucleus of the hypothalamus and in extrahypothalamic brain areas, on neurotrophin and neurotrophin receptor expression in the hippocampus and basal forebrain in basal conditions, and after neurotoxic challenges. Effects of hypothyroidism are discussed in view of a possible role of thyroid status in brain aging quality.     

A Study of Somatostatin Receptors in Amygdaloid-Kindled Rat Brain

Abstract. The present study indicates that in kindled rats there are no differences in the total number or affinity of the binding sites in the temporal cortex and a slight increase in the total number of binding sites in the cortex when compared with controls. These results, in view of our other observations, suggest that in the kindled rat brain there may be an increased release of SRIF but no down-regulation of SRIF receptors in the temporal cortex and cortex. There appears to be a significant decrease in the number of SRIF receptors in kindled hippocampus. The mechanism by which this occurs remains unclear.     

Long-Term Depression in Rat Cerebellum Requires both NO Synthase and NO-sensitive Guanylyl Cyclase

Long-term depression (LTD) of synaptic transmission between parallel fibres and Purkinje cells is a well-known example of synaptic plasticity taking place in the cerebellum. Nitric oxide (NO) has been implicated in synaptic plasticity in other brain areas, but its function in cerebellar LTD is controversial. Even when an involvement is suggested, the NO signal transduction pathway is unclear. One candidate is the cyclic GMP-synthesizing enzyme, soluble guanylyl cyclase, whose activity in the brain and elsewhere is powerfully stimulated by NO. By recording intracellularly from Purkinje cells in cerebellar slices, we demonstrate that blockade of NO synthase completely inhibits LTD induced by pairing parallel fibre stimulation with postsynaptic Ca²⁺ spike firing. LTD was also blocked by intracellular application of 1H-[1, 2, 4]oxadiazolo[4, 3-a]quinoxalin-1-one, a recently identified potent and selective inhibitor of soluble guanylyl cyclase. These findings indicate that soluble guanylyl cyclase is required for cerebellar LTD and suggest that this enzyme, located within Purkinje cells, transduces the NO signal in this form of synaptic plasticity.     

Calcitonin Gene-related Peptide Stimulates the Induction of c-fos Gene Expression in Rat Astrocyte Cultures

The action of calcitonin gene-related pepide (CGRP) was studied on c-fos gene expression in rat astrocyte cultures. A strong and transient increase in c-fos mRNA was observed in cultured astrocytes after treatment with CGRP. Quantitative Northern blot analysis revealed an increase of c-fos mRNA within 15 min, a peak after 30 min with a 10 - 15 fold increase over unstimulated cells and a subsequent decline. Induction of the c-fos gene by CGRP was concentration-dependent, half maximal stimulation of c-fos mRNA being obtained with 100 nM CGRP. The CGRP effect appeared to be mediated by a CGRP receptor and calcitonin was found to mimic only weakly the action of CGRP on cultured astrocytes. Calcitonin transiently induced c-fos gene expression with a similar time course to CGRP, but its effect was much less pronounced. Agents affecting the intracellular cyclic AMP level, forskolin and Ro 20-1724, stimulated c-fos mRNA in a strong and transient fashion with a temporal sequence similar to the response to CGRP. Further, the phosphodiesterase inhibitor Ro 20-1724 potentiated the action of CGRP on c-fos mRNA induction, suggesting a role for cyclic AMP in the action of CGRP. The present results indicate that CGRP may play a physiological role as a regulator of astrocyte gene expression.     

Early Changes in Prodynorphin mRNA and ir-Dynorphin A Levels after Kindled Seizures in the Rat

Prodynorphin mRNA and immunoreactive dynorphin A (ir-dynorphin A) levels were measured in different brain areas at various time points after amygdala kindled seizures. In the hippocampus, striatum and hypothalamus, prodynorphin mRNA levels were not significantly changed in kindled rats (killed 1 week after the last stimulus-evoked seizure), but they were significantly increased 1 h after seizures. The relative increase was the highest in the hippocampus (∼3-fold). In the brainstem, midbrain and cerebral cortex no changes in prodynorphin mRNA were detected in kindled rats, 1 h or 1 week after a kindled seizure. ir-Dynorphin A levels were significantly reduced in the hippocampus and in the striatum of kindled rats, as well as 5 and 60 min after kindled seizures, but they were increased back to control levels after 120 min. In the hypothalamus, ir-dynorphin A levels were significantly increased 120 min after a kindled seizure. ir-Dynorphin A levels were also significantly reduced in the brainstem and in the frontal, parietal and temporal cortex 120 min, but not 5 or 60 min, after a kindled seizure. Taken together, these data support the hypothesis that the dynorphinergic system is activated after amygdala kindled seizures, with different kinetics in different brain areas.     

Regional and age-dependent expression of the nitric oxide receptor, soluble guanylyl cyclase, in the human brain

Nitric oxide (NO), synthesized by neuronal NO synthase (NOS-I), plays essential physiological roles in the brain. The major molecular target for NO is soluble guanylyl cyclase (sGC), a heterodimeric hemoprotein composed of a larger alpha and a smaller beta subunit. Both subunits of sGC are needed to generate the second messenger cyclic GMP (cGMP). Here we show using subunit-specific antibodies and Western blot analysis that sGCalpha1 and sGCbeta1 protein subunits are present in all examined human brain regions. The relative distribution of the two subunits was similar and also correlated well with the known distribution of NOS-I. The highest expression levels of sGC were found in cortex, basal ganglia and the limbic system. These regions display the most prominent biochemical and histological changes during ageing. In cortex, a negative correlation between the amounts of sGC and age was found, while sex and post-mortem delay time did not affect sGC levels significantly. Our data suggest that sGCalpha1 and sGCbeta1 subunits are widely distributed in human brain, consistent with a major role in NO signaling. Moreover, the NO/cGMP pathway appears to be affected by ageing in the human brain.     

远隔缺血预处理诱导大鼠缺血脑保护的基因表达谱分析

目的检测远隔缺血预处理对大鼠缺血半暗带脑组织基因表达的影响,探讨远隔缺血预处理诱导的内源性脑保护机制。方法雄性SD大鼠24只随机分为常规缺血组(n=12)和远隔预处理组(n=12)。常规缺血组应用远端大脑中动脉阻塞术(dMCAO)建立局灶性脑缺血模型;远隔预处理组给予左侧股动脉15 min夹闭/15 min再通3个循环缺血预处理后,再予以dMCAO。两组大鼠分别在缺血1、3、6和24 h后取脑,采用Agilent大鼠全基因组芯片检测两组脑缺血半暗带区基因表达的变化,获取差异表达基因,并对差异基因进行GO分析和Pathway功能注释(KEGG数据库)。结果远隔缺血预处理后:①缺血半暗带区脑组织基因出现差异表达(P0.05且差异倍数2),随着缺血时间延长差异基因个数逐渐增加,在缺血6 h达高峰;②GO分析结果提示差异基因涉及刺激反应、生长、生物调节、细胞杀伤等多个生物过程;③对差异基因进行KEGG通路分析,结果提示Jak-STAT信号通路、p53信号通路、丝裂原蛋白激酶(MAPK)信号通路、谷氨酸突触信号通路、血管内皮生长因子(VEGF)信号通路等多条分子通路出现差异调节,差异调节通路的数目也在缺血6 h达高峰。结论远隔缺血预处理诱导半暗带基因差异表达,差异基因通过多条分子通路影响多个生物过程。基因表达谱芯片为远隔缺血预处理脑保护机制提供了全面的数据和信息,对各个靶点、各条通路的进一步深入研究具有全面、广泛的指导意义。     

Alterations in Cyclic AMP Concentration and Adenylate Cyclase Activity in Specific Brain Areas of Rats with Inherited Hypothalamic Diabetes Insipidus (Brattleboro Rats)

The concentration of cyclic AMP (cAMP) and the activity of sodium-fluoride-stimulated adenylate cyclase was measured in 29 microdissected brain areas of homozygous Brattleboro rats and their Long-Evans control rats. In ten of the investigated brain areas a decreased cAMP level was measured in Brattleboro rats. It was particularly decreased in the supraoptic nucleus, cingulate and parietal cortex, hippocampus, habenula and organum vasculosum laminae terminalis. Significantly lower cAMP levels were also found in the periventricular nucleus, bed nucleus of the stria terminalis, area postrema and locus coeruleus. An increased cAMP concentration was detected only in the subcommissural organ of Brattleboro rats. In most brain areas, where cAMP was decreased, sodium fluoride-stimulated adenylate cyclase activity was significantly increased (supraoptic nucleus, parietal cortex, periventricular nucleus, bed nucleus of the stria terminalis, locus coeruleus) or unchanged (hippocampus, habenula, organum vasculosum laminae terminalis). The coincidence of alterations in cAMP concentration and adenylate cyclase activity in brain areas of Brattleboro rats with relatively dense vasopressinergic innervation and/or vasopressin receptor population in control rats, suggests an influence of brain vasopressin on the cAMP-adenylate cyclase second messenger system.     

Distribution of Tyrosine Hydroxylase mRNA in the Rat Central Nervous System Visualized by Alkaline Phosphatase in situ Hybridization Histochemistry

The expression of tyrosine hydroxylase mRNA in the rat brain was examined using a novel alkaline phosphatase labelled antisense oligodeoxynucleotide probe. The alkaline phosphatase labelled probe revealed the presence of tyrosine hydroxylase mRNA in all the major cell groups and cell bodies previously described as containing catecholamine fluorescence or known to contain tyrosine hydroxylase immunoreactivity. Using standardized development protocols qualitative comparisons between the amount of mRNA signal in different adrenergic, noradrenergic or dopaminergic cell groups could be made. These studies showed that of the three known catecholaminergic cell types the level of tyrosine hydroxylase mRNA signal was high in the noradrenergic and dopaminergic cells, but much lower in the adrenergic cell groups. The sensitivity of this nonradioactive method of in situ hybridization is excellent and has considerable potential for studies of coexistence or coexpression of two mRNA signals for the localization of mRNA signals at the electron-microscope level.     

Chronic Ethanol-Induced Glial Fibrillary Acidic Protein (GFAP) Immunoreactivity: An Immunocytochemical Observation in Various Regions of Adult Rat Brain

In the present study, the effects of chronic ethanol (ETOH) treatment on the glial fibrillary acidic protein (GFAP) immunoreactivity was investigated in adult rat brains. ETOH were administered as increasing concentrations of 2.4%–7.2% (v/v) gradually for 21 days. Immunocytochemistry revealed that chronic-ETOH treatment increased synthesis of GFAP. The increase in the diameter and the number of GFAP (+) cells were statistically significant compared with the control group (p <. 05). An increase of GFAP immunoreactivity was evident in various white matter and gray matter structures. We concluded that functional astrocytic cells responded to chronic ETOH exposure by increasing the synthesis of GFAP.     

小鼠胚胎干细胞在成年大鼠脑内区域特异性生长

目的:探讨小鼠胚胎干细胞(mESC)在成年大鼠大脑内不同部位的存活,生长与分化的差异。方法:将少量mESC移植入成年大鼠脑内不同部位,于移植后5、14和28d后处死大鼠,进行形态学观察及免疫荧光定性。结果:移植的mESC在海马生长最为旺盛,而隔区最差(P<0.01);移植细胞分化为神经干细胞的效率也是海马最高,而隔区最低(P<0.01)。结论:只有部分脑区适合于mESC及其后裔生存并促进其分化,表明了宿主组织特性在细胞移植治疗中具有重要性。     

大鼠二次脑损伤后脑内c-fos基因表达和血浆β-内啡肽的变化及意义

目的 探讨脑内c-fos基因表达及血浆β-内啡肽的变化在二次脑损伤（SBI）中的作用。方法 125只雄性SD大鼠随机分为正常对照组、假手术组、脑缺血组、颅脑损伤组和SBI组。分别采用免疫组化及放免分析测定大鼠脑内c-fos蛋白与血浆β-EP的含量，并对脑组织进行病理学观察。结果 SBI组c-fos基因表达分别于伤后3h、24h出现两个高峰．伤后3～48hc-fos基因表达均明显高于颅脑损伤组及脑缺血组（P〈0．05）。SBI组大鼠血浆β-EP水平在伤后1h达高峰，至伤后48h仍未恢复正常（P〈0．05），伤后各时间点均明显高于颅脑损伤组和脑缺血组（P〈0．05）。在伤后12hSBI组脑含水量达高峰；伤后3～48h明显高于颅脑损伤组及脑缺血组（P〈0．05）。伤后648hSBI组神经元损伤数目明显高于颅脑损伤组及脑缺血组（P〈0．05）。结论 伤后大鼠脑内c-fos基因表达增加、血浆β-EP水平明显升高参与了SBI后病理生理过程，提示两者同SBI发展密切相关。     

慢性痛大鼠背根神经元基因表达的研究

目的研究与慢性痛相关基因的特异表达,比较大鼠背根神经节损伤神经元与正常神经元之间基因表达的差异,以寻找构成神经病性疼痛的内在因素。方法应用mRNA差异显示方法从损伤背根神经节中寻找特异表达的基因。结果损伤侧背根节中cDNA条带(25.75±4.7)明显多于对照侧(18.0±5.0)。反向杂交后进行亚克隆得到10个含插入片段的阳性质粒,并对其中4个进行测序。结论神经轴突损伤可导致胞体基因表达改变,其中某些可能与痛觉异常有关,也可能与细胞结构恢复及免疫功能改变有关。