脂多糖预处理改善脂多糖诱导的中脑脑片神经元损伤

目的探讨脂多糖（lipopolysaccharide,LPS）预处理对脂多糖所致中脑脑片多巴胺能神经元炎性损伤的影响及其可能的机制。方法建立大鼠中脑脑片体外培养体系,于体外培养14d后以不同剂量脂多糖（0、1、3、6及10ng／mL）预处理24h,然后用大剂量脂多糖（100ng／mL）作用72h,观察脂多糖预处理对脑片乳酸脱氢酶（lactic acid dehydrogenase,LDH）活性的影响。通过免疫组化检测酪氨酸羟化酶（Tyrosine hydroxylase,TH）和OX-42的阳性细胞数变化,应用酶联免疫吸附法测定培养液上清肿瘤坏死因子-α（tumor necrosis factor-α,TNF-α）水平。结果100ng／mL多糖作用72h后引起脑片TH阳性细胞数从对照组的191±12减少到46±4,LDH活性明显升高（P〈0．01）,小胶质细胞大量激活,TNF-α水平显著增高（P〈0．01）。脂多糖预处理能减少神经细胞的丢失（3ng／mL和6ng／mL的LPS处理后TH阳性细胞数分别为126±12和180±13）,降低脑片LDH活性（P〈0．05）,并有效地抑制小胶质细胞的激活,明显减少TNF-α的生成（P〈0．05）。结论小剂量脂多糖预处理可改善脂多糖对大鼠中脑脑片多巴胺能神经元的损伤,其作用机制可能是通过抑制小胶质细胞的激活,减少TNF-α的释放,减轻炎症反应对神经元的损伤。这种保护作用可为帕金森氏病的治疗提供新思路。     

甘草黄酮对脂多糖诱导小胶质细胞i NOS表达和NF-кB活化影响

目的研究甘草黄酮对脂多糖诱导的BV-2小胶质细胞诱导型一氧化氮合酶(inducible nitricoxide,iNOS)表达影响和对核因子-kB(nuclear factor-kappa B,NF-kB)活化的影响。方法将BV-2细胞随机分为四个组:Control组、脂多糖组、3μg/mL和5μg/mL甘草黄酮处理组。采用免疫荧光染色法定性分析iNOS在BV-2细胞的表达;采用免疫蛋白印迹法定量分析甘草黄酮处理前后胞浆iNOS蛋白表达量和胞核NF-кB p65蛋白含量变化。结果各组i NOS阳性BV-2细胞数量(F=8.09,P0.01),胞浆iNOS蛋白表达量(F=7.89,P0.01)和胞核NF-кB p65蛋白含量(F=6.12,P0.01)差异均有统计学意义。被脂多糖刺激后,大量BV-2细胞呈iNOS阳性(P0.01),部分细胞胞体变圆钝,突起变粗短;胞浆iNOS蛋白表达量较对照组急剧增多(P0.01),同时伴有胞核NF-кB p65蛋白含量的显著增加(P0.01)。而经两种浓度脂多糖处理过的BV-2细胞,在脂多糖刺激后,iNOS阳性细胞数量则均较脂多糖组有明显减少(P0.01),同时细胞胞体缩小,突起增多;胞浆iNOS蛋白表达量也均较脂多糖组有明显降低(P0.01),同时伴有胞核NF-кB p65蛋白含量的降低(P0.01)。结论甘草黄酮可抑制脂多糖诱导的小胶质细胞iNOS表达,其机制可能与调节NF-кB活化有关。     

选择性5-羟色胺再摄取抑制剂对小胶质细胞不同活化途径的影响

目的 探讨SSRIs氟西汀和艾司西酞普兰对于小胶质细胞不同活化途径的影响.方法 新生2 dSD大鼠脑组织经洗涤、分离、消化、过筛网、离心等处理,获得原代小胶质细胞.将BV2细胞系组和原代细胞组进一步分亚组如下:空白对照组、M1型模型组、M2型模型组、氟西汀组和艾司西酞普兰组,干预24h后使用实时定量聚合酶链式反应(real-time quantitative polymerase chain reaction,RT-PCR)、酶联免疫吸附测定(enzyme linked immunosorbent assay,ELISA)和免疫印迹法测定相关炎症指标表达水平.结果 (1)M1型活化:RT-PCR示氟西汀可显著降低脂多糖联合干扰素-γ(LPS+INF-γ)诱导的BV2细胞白细胞介素1β(interleukin 1β,IL-1β)、IL-6、肿瘤坏死因子a(tumor necrosis factor,TNF-a)和诱导型一氧化氮合成酶(inducible nitric oxide synthase,iNOS)mRNA表达(均P＜0.05).氟西汀和艾司西酞普兰均可显著抑制LPS+ INF-γ诱导的原代小胶质细胞IL-6(均P＜0.01)、TNF-a(P =0.018、0.029)和iNOS(均P=0.005)mRNA表达.免疫印迹法示氟西汀和艾司西酞普兰可显著抑制LPS+ INF-γ诱导的BV2细胞Iba-1 (P ＜0.01、P=0.002)、CD86(均P＜0.01)蛋白表达.氟西汀和艾司西酞普兰均可显著抑制LPS+ INF-γ诱导的原代小胶质细胞CD86表达(均P＜0.01).ELISA示氟西汀可显著抑制LPS+ INF-γ诱导的BV2细胞TNF-a(P=0.003)和IL-1 β(P=0.002)分泌.氟西汀和艾司西酞普兰可显著抑制LPS+ INF-γ诱导的原代小胶质细胞IL-1β分泌(均P＜0.01).原代小胶质细胞各组间TNF-a分泌差异无统计学意义(F=4.627,P=0.053),进一步组间比较示与模型组[(11.6±1.1)g/L]相比,艾司西酞普兰组[(20.2±1.9) g/L]TNF-a表达增高(P=0.012).(2)M2型活化:RT-PCR示氟西汀可显著提高IL-4诱导的原代小胶质细胞IL-10 mRNA表达(P=0.036).免疫印迹法示氟西汀可显著提高IL-4诱导的BV2细胞(P=0.016)和原代小胶质细胞(P＜0.01)CD206表达.ELISA示氟西汀可显著提高IL-4诱导的BV2细胞(P=0.044)和原代小胶质细胞(P＜0.01)IL-10分泌.结论 氟西汀和艾司西酞普兰可通过影响小胶质细胞活化状态而发挥免疫调节作用,这可能是SSRI类抗抑郁剂发挥抗抑郁作用机制之一.     

绞股蓝皂苷对原代培养胚鼠中脑多巴胺能神经细胞的保护作用

目的 探讨绞股蓝皂苷(GPs)对原代培养的胚鼠中脑多巴胺(DA)能神经细胞的保护作用. 方法原代培养胎鼠中脑腹侧神经细胞,分别应用100、200、400、800μg/mL GPs作用6 h、12 h、24 h、48 h、72 h、96 h,同时设空白对照组和阳性对照(NGF)组,应用MTT比色试验检测GPs对细胞活性的影响,筛选GPs的最佳作用浓度和时间.免疫细胞化学染色检测抗酪氨酸羟化酶(TH)的表达;应用1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)诱导细胞损伤,同时设空白对照组和GPs预处理组,应用免疫细胞化学染色和流式细胞仪分别检测诱导型一氧化氮合酶(iNOS)的表达和细胞凋亡.结果 MTT检测结果显示400μg/mL GPs作用48h后细胞活性最高,与NGF组比较差异无统计学意义(P>0.05).TH免疫染色显示400μg/mL GPs组和NGF组TH阳性细胞数均高于空白对照组,差异有统计学意义(P<0.05);iNOS免疫染色和流式细胞仪检测显示400 μg/mL GPs预处理组iNOS阳性细胞数和细胞凋亡率高于空白对照组,但仍低于MPTP组,差异均有统计学意义(P<0.05).结论 400μg/mL GPs作用48 h对MPTP诱导的DA能神经细胞的损伤具有保护作用.     

美满霉素对脂多糖诱导的BV-2小胶质细胞肿瘤坏死因子-α表达的影响

目的探讨美满霉素(MC)对脂多糖(LPS)诱导的BV-2小胶质细胞肿瘤坏死因子-α(TNF-α)表达的影响。方法采用相应浓度的MC或LPS(100 ng/ml)对MC组及0.1、1、10、100μmol/L MC+LPS组、LPS组、空白对照组BV-2小胶质细胞进行预处理。ELISA法检测BV-2小胶质细胞TNF-α蛋白的表达,逆转录-PCR检测细胞TNF-αmRNA表达。结果与空白对照组比较,0.1、1μmol/L MC+LPS组及LPS组的TNF-α水平显著升高(均P0.01)。10、100μmol/L MC+LPS组TNF-α水平显著低于LPS组(均P0.01)。与空白对照组比较,LPS组及10μmol/L MC+LPS组TNF-αmRNA的表达水平显著增高(均P0.01)。10μmol/L MC+LPS组TNF-αmRNA表达水平显著低于LPS组(P0.01)。结论 MC预处理(≥10μmol/L)可显著抑制LPS诱导的小胶质细胞TNF-α的表达。     

GSTP1通过调节JNK通路抑制癫痫大鼠海马区星形胶质细胞炎性激活

目的 明确谷胱甘肽硫转移酶P1(GSTP1)对星形胶质细胞炎性激活的影响及相关分子机制。方法 10周龄雄性SD大鼠采用腹腔注射氯化锂建立癫痫模型(n=8)并收集海马区脑组织。大鼠原代星形胶质细胞给予不同浓度脂多糖(0μg/ml、0.1μg/ml、1μg/ml、10μg/ml、100μg/ml)诱导处理48 h。利用蛋白质印迹检测组织与细胞中GSTP1、JNK、p-JNK蛋白表达水平，以酶联免疫吸附试验检测TNF-α、IL-1β、IL-6浓度，以高效液相色谱测定谷氨酸(Glu)浓度。将GSTP1过表达载体瞬时转染至脂多糖诱导星形胶质细胞，并给予茴香霉素处理，观察星形胶质细胞炎性激活情况。结果 癫痫大鼠海马区脑组织中GSTP1蛋白表达水平低于正常大鼠，而p-JNK蛋白表达水平与TNF-α、IL-1β、IL-6、Glu浓度高于正常大鼠(P<0.05)。GSTP1与p-JNK蛋白表达水平呈负相关(P<0.05)。脂多糖诱导星形胶质细胞炎性激活，表现为GSTP1蛋白表达水平呈剂量依耐性降低，而p-JNK蛋白表达水平与TNF-α、IL-1β、IL-6、Glu浓度呈剂量依耐性升高(P&l...     

细菌脂多糖诱导活性小胶质细胞对少突胶质细胞前体的毒性作用

已有实验证实,脑白质病变如多发性硬化症和脑室周围白质软化等一些神经病变的发病机制,均涉及到局部小胶质细胞的激活。 目的：探讨细菌脂多糖诱导活性小胶质细胞对少突胶质细胞前体的毒性作用。 方法：取2 d龄SD大鼠脑内小胶质细胞和少突胶质细胞前体共培养,分为共培养对照组和共培养脂多糖组。对共培养细胞经脂多糖100 μg/L 诱导48 h,分别应用硝酸还原比色法检测一氧化氮含量,还原-比色法检测超氧阴离子含量,免疫细胞染色法检测过氧亚硝酸盐含量,Hochest33342/PI荧光染色法观察细胞死亡的形态学改变,以及流式细胞仪检测细胞成活率。 结果与结论：与共培养对照组比较,脂多糖诱导导致共培养细胞内一氧化氮、超氧阴离子、过氧亚硝酸盐含量均明显增加,少突胶质细胞前体的凋亡率亦显著增加。通过体外观察,确认脂多糖诱导少突胶质细胞前体的死亡通路,是由于脂多糖诱导小胶质细胞激活,导致小胶质细胞表达一氧化氮合酶和活化NADPH氧化酶,致使其产物一氧化氮和超氧阴离子大量生成,两者进一步反应生成大量的毒性因子过氧亚硝酸盐,作用于少突胶质细胞前体,从而导致少突胶质细胞前体的死亡。     

塞来昔布对脂多糖诱导的原代多巴胺能神经元变性的保护作用

目的研究COX-2选择性抑制剂塞来昔布对脂多糖诱导的中脑原代多巴胺能神经元变性的保护作用及其机制。方法将培养7d的孕14d SD大鼠胚胎中脑原代细胞随机分为4组:对照组、脂多糖(LPS)组(20ng/ml)、塞来昔布(20μmol/L) 脂多糖组、单纯塞来昔布组。培养72h后使用免疫荧光染色观察酪氨酸羟化酶(TH)、OX-42阳性细胞数目和形态变化,放免法测定上清液中前列腺素E2(PGE2)和肿瘤坏死因子-α(TNF-α)水平。结果塞来昔布 LPS组和LPS组比较:TH阳性细胞数目明显增多,分别为对照组的69%和48%(P<0.05);OX-42阳性细胞数目明显减少,分别为对照组的2和3.48倍(P<0.05)。形态上分析塞来昔布显著改善LPS对TH阳性细胞的损伤程度和抑制LPS诱导的小胶质细胞体积增大、形态不规则。同时抑制LPS诱导的PGE2和TNF-α含量的增加(P<0.05)。结论塞来昔布通过抑制小胶质细胞激活以及COX-2表达,减少细胞外PGE2、TNF-α水平发挥其神经保护作用。     

凝血酶诱导的小胶质细胞激活促进多巴胺能神经元变性

目的探讨凝血酶（Thrombin）诱导小胶质细胞（Micoglia）激活与黑质多巴胺能神经元变性的关系。方法采用立体定向术注射凝血酶至大鼠黑质,在不同时间点观察酪氨酸羟化酶（tyrosine hydroxylase,TH）神经元的表达及小胶质细胞的激活情况;同时检测黑质NO量及iNOS mRNA表达。结果（1）凝血酶注入大鼠黑质导致明显的黑质多巴胺能神经元变性,呈时间依赖性,TH阳性细胞数在第3d开始下降,第7d有大量的TH阳性细胞丢失,与对照侧相比下降达约53％（P〈0．01）;高倍镜下可见胞体皱缩、突起明显缩短或减少;14d时细胞数下降至21％,30d时下降至12％（P〈0．01）。（2）凝血酶注射入黑质4h后小胶质细胞开始呈现为“灌木丛样”或少量呈现“阿米巴样”：12h后小胶质细胞数目明显增加且绝大部分呈现“阿米巴样”;24h后细胞已完全激活,“阿米巴样”细胞达高峰;3d维持高峰;14d后小胶质细胞染色变淡,体积变小,“阿米巴样”细胞数目下降。（3）与对照组相比,iNOSmRNA表达明显上调及NO合成增加（P〈0．05）,并且有iNOS在小胶质细胞表达。结论凝血酶对多巴胺能神经元具有一定的损毁作用,小胶质细胞的激活先于多巴胺能神经元变性,其激活后释放的NO有可能参与多巴胺能神经元变性。     

帕金森病炎症/免疫异常细胞模型的建立

目的 观察小胶质细胞激活后形态和功能的变化。以探讨活化的小胶质细胞对多巴胺能神经元产生损伤作用的可能机制。阐明帕金森病发病的免疫机制。方法 建立原代小胶质细胞培养。筛选和鉴定的方法，以细菌细胞壁脂多糖为工具药激活小胶质细胞，通过免疫组化，MTT，ELISA等方法观察小胶质细胞形态，数量和功能的文化。结果 LPS激活的小胶质细胞体积增大，OX-42表达上调，释放一氧化氮（NitricOxide,NO)，合成超氧阴离子（O2）及分泌细胞因子TNF-α量显著增多，而细胞数量无明显改变。结论 激活的小胶质细胞对多巴胺能神经元的损伤作用。可能与释放NO，O2^-及细胞因子TNF-α等细胞毒性物质有关。     

Increased preproenkephalin mRNA and preprotachykinin mRNA in the striatum of Rolling mouse Nagoya

Although Rolling mouse Nagoya (RMN) has been considered to demonstrate cerebellar dysfunction, our previous metabolic and electrophysiological studies also revealed a dysfunction of the basal ganglia, with the presumable primary site of dysfunction being the striatum. In the present study., we investigated the neurochemical functions of the striatum. In RMN, both preproenkephalin mRNA and preprotachykinin mRNA increased significantly in the striatum, with unaltered GAD mRNA, [³H]spiperone binding, [³H]QNB binding and preprosomatostatin mRNA, thus indicating the dysfunction of striatal projection neurons. These findings support the hypothesis that the site of primary dysfunction in the basal ganglia is in the striatum of RMN.     

Effect of pentylenetetrazol on the expression of tyrosine hydroxylase mRNA and norepinephrine and dopamine transporter mRNA

Seizure activity has been shown to have differential effects on the terminal content of the monoamines, norepinephrine (NE) and dopamine (DA). Induction of seizure activity reduces the terminal content of NE, while DA levels remain unchanged or slightly elevated. This study examined the effect of the chemoconvulsant pentylenetetrazol (PTZ) on the mRNA expression of regulatory proteins which maintain the terminal content of NE and DA (i.e., synthesis and re-uptake). The areas examined were the noradrenergic neurons of the locus coeruleus (LC) and dopaminergic neurons of the substantia nigra pars compacta/ventral tegmentum area (SNpc/VTA) in the rat. In the LC, PTZ increased mRNA expression of the immediate early gene, c-fos, and mRNA expression of the synthesizing enzyme, tyrosine hydroxylase (TH), and the re-uptake protein, norepinephrine transporter (NET). This effect on TH and NET was observed only 1 day after the administration of PTZ. In contrast, PTZ did not alter the expression of c-fos mRNA in the SNpc/VTA, but reduced the expression of the dopamine transporter (DAT) mRNA. This effect was observed only 1 day after the administration of PTZ. TH mRNA expression in dopaminergic neurons was elevated initially in a manner similar to that observed in the LC. However, the effect of PTZ on TH mRNA expression in dopaminergic neurons was more prolonged (still elevated 3 days later). These results indicate that the chemoconvulsant PTZ has differential effects on the mRNA expression of regulatory systems (TH and neurotransporter proteins) in noradrenergic and dopaminergic neurons.     

Cloning and distribution of the rat parkin mRNA

We have isolated by RT-PCR and sequenced a partial cDNA coding for the rat homolog of parkin, a gene mutated in autosomal recessive juvenile parkinsonism. The 1.46 kb rat cDNA clone contains a 1376 bp coding sequence that shares strong similarity with the human parkin cDNA. RT-PCR and in situ hybridization revealed widespread expression of parkin in the rat brain and the periphery. The availability of the rat parkin cDNA and the initial elucidation of its distribution should facilitate further research on the pathophysiological role of parkin in the nervous system.     

Regulation of glucocorticoid receptor mRNA and heat shock protein 70 mRNA in the developing sheep brain

Fetal hypothalamo-pituitary-adrenal (HPA) activity increases dramatically at term in sheep, however, little is known about the regulation of glucocorticoid feedback in the developing brain. Heat shock protein 70 (hsp70) is closely associated with glucocorticoid actions within the cell. We hypothesized that there is a decrease in glucocorticoid negative feedback in the brain, near term, resulting from changes in the expression of glucocorticoid receptors (GR) and hsp70. Brains were removed at various stages of development. GR mRNA levels in the paraventricular nucleus (PVN) and cortex, and hsp70 mRNA in the PVN were determined by in situ hybridization. In the hippocampus, GR mRNA levels were measured by Northern analysis. In the PVN, GR mRNA was present by d60. GR mRNA levels reached a peak at d100-110, but then decreased significantly with progression of gestation, and were lowest at term. Hippocampal GR mRNA levels were highest on day 130 of gestation, decreasing to low levels at term. In the cerebral cortex, GR mRNA levels were expressed at high levels in all layers of the cortex by day 110 of gestation with levels decreasing to term. Hsp70 mRNA was present in both parvocellular and magnocellular regions of the PVN, and there was no significant change in late gestation. In conclusion, (1) The high levels of GR mRNA present in the PVN, hippocampus and cerebral cortex during fetal life are likely important in development of these structures at a time when circulating glucocorticoids are low. (2) Changes in GR mRNA levels in the PVN are not associated with alterations in the expression of hsp70. (3) The decrease in GR mRNA in the hippocampus and PVN in late gestation, at a time when fetal plasma cortisol is increasing, likely facilitates maintained hypothalamic drive to the pituitary corticotroph.     

槲皮素对糖尿病脑梗死大鼠脑纤溶激活系统基因表达的研究

目的 观察槲皮素对糖尿病脑梗死大鼠脑组织中纤溶酶原激活物(t-PA)及其抑制剂 mRNA表达的影响.方法 Wistar大鼠50只,随机分为正常假手术组、糖尿病假手术组、糖尿病脑梗死组、低剂量与高剂量槲皮素预处理组5组.后4组大鼠制作糖尿病模型.造模后低剂量与高剂量槲皮素预处理组分别按体质量予槲皮素50 mg/(kg·d)、100 mg/(kg·d)灌胃15 d,并与糖尿病脑梗死组行自体血栓脑梗死处理.以半定量反转录-聚合酶链式反应法(RT-PCR)检测各组动物脑组织中组织型纤溶酶原激活物(t-PA) mRNA、尿激酶型纤溶酶原激活物(u-PA) mRNA、1型纤溶酶原激活物抑制剂(PAI-1) mRNA、神经丝氨酸蛋白酶抑制剂(NSP) mRNA的表达并进行分析比较.结果 与糖尿病脑梗死组t-PA mRNA、PAI-1 mRNA相对表达量(分别为0.27±0.03、0.68±0.06)比较,低剂量、高剂量槲皮素预处理组t-PA mRNA表达(分别为0.32±0.05、0.44±0.10)升高,PAI-1 mRNA表达(0.53±0.15、0.32±0.07)降低(均P<0.01),高剂量、低剂量槲皮素预处理组、糖尿病脑梗死组之间u-PA mRNA、NSP mRNA表达无统计学差异.结论 槲皮素可能通过促进t-PA mRNA表达、抑制PAI-1 mRNA表达改善糖尿病脑梗死大鼠纤溶功能.槲皮素预处理对糖尿病脑梗死大鼠u-PA mRNA、NSP mRNA表达无明显影响.     

Differential regulation of glutamic acid decarboxylase mRNA and tyrosine hydroxylase mRNA expression in the aged manganese-treated rats

Recent studies have implicated chronic elevated exposures to environmental agents, such as metals (e.g. manganese, Mn) and pesticides, as contributors to neurological disease. Eighteen-month-old rats received intraperitoneal injections of manganese chloride (6 mg Mn/kg/day) or equal volume of saline for 30 days in order to study the effect of manganese on the dopamine- and GABA-neurons. The structures studied were substantia nigra, striatum, ventral tegmental area, nucleus accumbens and globus pallidus. First, we studied the enzymatic activity of mitochondrial complex II succinate dehydrogenase (SDH). We found an overall decrease of SDH in the different brain areas analyzed. We then studied the mRNA levels for tyrosine hydroxylase (TH) and the dopamine transporter (DAT) by in situ hybridization. TH mRNA but not DAT mRNA was significantly induced in substantia nigra and ventral tegmental area following Mn treatment. Correspondingly, TH immunoreactivity was increased in substantia nigra and ventral tegmental area. Manganese treatment significantly decreased GAD mRNA levels in individual GABAergic neurons in globus pallidus but not in striatum. We also quantified the density of glial fibrillary acidic protein (GFAP)-labeled astrocytes and OX-42 positive cells. Reactive gliosis in response to Mn treatment occurred only in striatum and substantia nigra and the morphology of the astrocytes was different than in control animals. These results suggest that the nigrostriatal system could be specifically damaged by manganese toxicity. Thus, changes produced by manganese treatment on 18-month-old rats could play a role in the etiology of Parkinson's disease.     

Action of interleukin-2 and interleukin-4 on CRF mRNA in the hypothalamus and POMC mRNA in the anterior pituitary.

We have used the technique of in situ hybridization histochemistry to determine corticotropin-releasing factor (CRF) mRNA in the hypothalamic paraventricular nucleus (PVN) and proopiomelanocortin (POMC) mRNA in the anterior pituitary of rats given a single ip injection of either interleukin (IL)-2 or IL-4. IL-2 increased POMC mRNA in the anterior pituitary in a dose-dependent manner. The effect was apparent both at 4 and 24 h after injection. No effect of IL-2 on CRF mRNA in the PVN was detected in these animals, suggesting that the increase in POMC mRNA was not driven by an increase in CRF. IL-4 was without effect at the hypothalamic level although this cytokine did result in a decrease in POMC mRNA in the anterior pituitary.     

Upregulation of BDNF mRNA and trkB mRNA in the nigrostriatal system and in the lesion site following unilateral transection of the medial forebrain bundle

We have performed unilateral transection of the medial forebrain bundle (MFB) and studied BDNF mRNA and trkB mRNA levels at different postlesion times in the nigrostriatal system by means of in situ hybridization. BDNF mRNA levels were transiently induced in the substantia nigra pars compacta at 1 day postaxotomy. The disposition of BDNF mRNA expressing cells at this postlesion time in substantia nigra mimicked that of the dopaminergic neurons expressing the mRNA for the dopamine transporter. TrkB mRNA levels remained unaltered in the ventral mesencephalon at the different postlesion times examined-1 to 14 days. In contrast, trkB mRNA levels were significantly induced in the striatum at the longer postlesion time examined-14 days-when all neurodegenerative events are completed. It is becoming apparent that nigral BDNF mRNA levels are anterogradely transported to its target tissue in striatum. However, following axotomy, the lesion site represents a second potential target for BDNF action. Consequently, we also analyzed the pattern of mRNA expression for BDNF and trkB at the lesion site where dopaminergic axons are disconnected. There, we found notable inductions of both BDNF mRNA and trkB mRNA levels at 4 days postaxotomy. BDNF mRNA expressing cells were confined at the site of axotomy, which coincided precisely to that showing induction of trkB mRNA. Altogether, our results anticipate promising trophic roles of BNDF in the injured nigrostriatal system.     

Perforant path stimulation differentially alters prodynorphin mRNA and proenkephalin mRNA levels in the entorhinal cortex-hippocampal region

The regulatory effect of the perforant path on opioid gene expression in the entorhinal cortex-hippocampal region was investigated. The left perforant path was electrically stimulated at the angular bundle under conditions which elicit wet dog shakes but no motor seizures in rats. Animals were given either an acute stimulation composed of several consecutive stimulation trials, or daily stimulations with a single trial every day for 6 days. Rats were then sacrificed at 24 h or 6 days after the last trial. The amounts of prodynorphin mRNA (DYN mRNA) and proenkephalin A mRNA (EK mRNA) in the hippocampus and entorhinal cortex were measured by RNA blot analysis. Dynorphin A(1-8) and [Met5]enkephalin immunoreactivities were determined by radioimmunoassay. A decrease in DYN mRNA level of approximately 50-80% was found on both sides of the hippocampus 24 h after both acute and daily stimulation. Hippocampal dynorphin A(1-8) immunoreactivity was also reduced at 24 h, and persisted for at least 6 days. In contrast, bilateral increases in EK mRNA level were observed in the hippocampus (54-101%) and entorhinal cortex (97-165%) 24 h after the acute stimulation. Also, [Met5]enkephalin immunoreactivity in the hippocampus tended to be increased at this time. These results indicate that activation of the perforant path inhibits the gene expression of prodynorphin, but enhances that of proenkephalin in the entorhinal cortex-hippocampal region.     

匹罗卡品致癎大鼠海马γ-氨基丁酸能中间神经元生长抑素和微清蛋白mRNA表达研究

目的观察匹罗卡品致癎大鼠海马γ-氨基丁酸能中间神经元生长抑素（SS）mRNA和微清蛋白（PV）mRNA表达水平变化,拟从基因水平探讨其表达阳性叮一氨基丁酸能中间神经元在颞叶癫癎发生发展中的作用。方法建立匹罗卡品致癎大鼠模型,采用原位杂交法检测各观察时间点海马SSmRNA和PVmRNA表达阳性神经元数目。结果模型组大鼠海马各区吖．氨基丁酸能中间神经元SSmRNA表达水平均于出现癫癎持续状态后3d降低最为显著（均P=0．000）,随后逐渐升高;至发病后60d,海马CA3区SSmRNA表达水平高于对照组（t=1．021,P=0．005）,海马门区（t=3．211,P=0．009）和CA1区（t=1．902,JP=0．048）则仍低于对照组。模型组大鼠海马门区γ-氨基丁酸能中间神经元PVmRNA表达水平于出现癫癎持续状态后6h开始降低,至发病后60d降低最为显著（均P：0．000）;海马CA1区PVmRNA表达水平于发病后3d降低最为显著（均p=0．000）,随后逐渐升高但仍低于对照组（t=2．216,尸：0．048）;癫癎持续状态早期,海马CA3区PVmRNA表达水平无明显变化,至发病后7d逐渐升高且高于对照组（t=1．021,P=0．005）。结论γ-氨基丁酸能中间神经元SSmRNA和PVmRNA表达水平的下调可能在颞叶癫癎的发生中起重要作用,至慢性期γ-氨基丁酸能中间神经元SSmRNA和PVmRNA表达水平的恢复或上调可能与颞叶癫癎的发展或修复有关。γ-氨基丁酸能中间神经元数目的变化,部分是由于其标志物mRNA表达水平的调节所致,并非神经元数目变化的唯一因素。