一氧化氮与帕金森病小鼠模型神经损害的研究

目的　研究一氧化氮（ＮＯ） 在帕金森病（ＰＤ）小鼠模型神经损害中的作用。方法　用比色分析、高效液相色谱电化学及免疫组化法检测１甲基４苯基四氢吡啶（ＭＰＴＰ）和７硝基吲唑（７ＮＩ）对Ｃ５７ＢＬ小鼠纹状体一氧化氮合酶（ＮＯＳ） 活性,多巴胺（ＤＡ）、二羟基苯乙酸（ＤＯＰＡＣ）、高香草酸（ＨＶＡ） 水平和酪氨酸羟化酶（ＴＨ） 免疫阳性神经纤维的影响。结果　注射ＭＰＴＰ后Ｃ５７ＢＬ小鼠纹状体ＮＯＳ活性增加,７ＮＩ能明显抑制ＭＰＴＰ引起的ＮＯＳ活性的升高（ 分别为０ ．９３ ±０．２４ 和０．５４ ±０．１６,ｎｍｏｌ·ｍｉｎ－１·ｇ－１ 组织,Ｐ＜０．０１） 。７ＮＩ能明显减轻ＭＰＴＰ引起的Ｃ５７ＢＬ小鼠纹状体ＤＡ（ 分别为０ ．８ ±０ ．２ 和６．８±０．５,μｇ／ｇ 组织,Ｐ＜０．０１） 、ＤＰＯＡＣ（ 分别为０．３ ±０．１ 和０ ．９ ±０ ．３ ,μｇ／ｇ 组织,Ｐ＜ ０ ．０１）、ＨＶＡ（分别为０．４±０．２ 和０．９ ±０ ．２,μｇ／ｇ 湿组织,Ｐ＜ ０．０１） 的降低及ＴＨ 阳性神经纤维损害。结论神经元来源的ＮＯ 参与了ＭＰＴＰ的毒性机制,神经元型ＮＯＳ抑制剂可能有益于ＰＤ的治疗。     

高频刺激底丘脑核阻止帕金森病黑质多巴胺能神经元变性的实验研究

目的评价电刺激底丘脑核（ＳＴＮ）对帕金森病黑质多巴胺能神经元变性的影响。方法　实验用大鼠随机分为四组：第１组　纹状体仅注射６－羟基多巴（６－ＯＨＤＡ）;第２组　底丘脑核区插入电极进行刺激组;第３组　底丘脑核刺激后６－ＯＨＤＡ再注射纹状体组;第４组　假刺激底丘脑核后再注射６－ＯＨＤＡ入纹状体组。手术后６周,分别观察各组大鼠阿朴吗啡（ＡＰＯ）诱发旋转行为及黑质多巴胺能神经元改变情况。结果第１、４组出现明显的ＡＰＯ诱发对侧旋转行为,第２、３组出现同侧旋转;酪氨酸羟化酶（ＴＨ）免疫组织化学染色显示,黑质区ＴＨ免疫反应（ＴＨ－ＩＲ）神经元数目在２、３组双侧无明显不同,而１、４组注射侧ＴＨ－ＩＲ神经元数目显著降低（Ｐ＜０．０１）。结论我们的结果表明,ＳＴＮ电刺激可以保护黑质多巴胺能神经元免受６－ＯＨＤＡ的毒性损害,提示这种治疗方法可以阻止或延缓帕金森病的继续发展和恶化。     

福尔马林炎症痛诱导的大鼠脊髓后角一氧化氮合酶的变化

用ＮＡＤＰＨ－黄递酶（ＮＡＤＰＨ－d）组化法观察福尔马林炎症性痛及痛过敏过程中脊髓后角一氧化氮合酶（NOS)的变化,特别是其时间特征。结果显示：与对照组相比,注射福尔马林后１２、２４及４８h组脊髓后角ＮＡＤＰＨ－d阳性细胞的数目及染色深度均显著增加,但以２４h组增加最为明显。结果表明福尔马林炎症性痛及痛过敏过程中,脊髓后角ＮＯＳ活性增强,且这种增强有一定的时间变化特征。     

大鼠脑缺血和再灌流过程脑组织一氧化氮合成酶表达的变化

目的　探讨大鼠脑缺血再灌流海马及皮层一氧化氮合酶（ＮＯＳ） 的变化。方法　用线栓法建立大脑中动脉梗死（ＭＣＡＯ） 模型,用烟酰胺腺嘌呤二核苷酸磷酸黄递酶（ＮＡＤＰＨｄ） 染色法观察ＮＯＳ阳性细胞的变化。结果　海马及皮层ＮＯＳ阳性细胞在缺血１５ 分明显增多,１ 小时减少,６ 小时有所恢复;再灌流１５ 分又显著减少,１ 小时渐增多,２４ 小时皮层出现较多ＮＯＳ阳性的毛细血管和大量胶质细胞。结论　本实验结果符合ＮＯ 在缺血早期增加和再灌流后期大量增加的变化,支持ＮＯ参与脑缺血再灌流损害的观点。     

高频刺激底丘脑核阻止帕金森病黑质多巴胺能神经元变性的 …

目的 评价电刺激底丘脑核（ＳＴＮ）对帕金森病黑质多巴胺能神经元变性的影响。方法 实验用大鼠随机分为四组：第１组 纹状体仅注射６－羟基多巴（６－０ＨＤＡ）;第２组 底丘脑核区插入电极进行刺激组;第３组 底丘脑核刺激后６－ＯＨＤＡ再注射纹状体组;第４组 假刺激 丘脑核后再注射６－ＯＨＤＡ入纹状体组。手术后６周,分别观察各组大鼠阿朴吗啡诱发旋转行为及黑质多巴胺能神经地改变情况。     

损毁丘脑底核阻止6—OHDA对大鼠多巴胺能神经元的损？…

目的观察不同时期毁损丘脑底核对大鼠中脑黑质多巴胺神经元６－羟基多巴胺（６－ＯＨＤＡ）损伤的保护作用。方法将６０只Ｗｉｓｔａｒ大鼠随机分为６组,每组１０只。对照组采用６－０ＨＤＡ立体定向注入大鼠右侧前脑内侧束（ＭＦＢ）和中脑被盖腹侧区（ＶＴＡ）,制成偏侧帕金森病（ＰＤ）模型。实验组分为第Ⅰ、Ⅱ、Ⅲ、Ⅳ和Ⅴ组,分别于６－ＯＨＤＡ注射前７ｄ、注射后１ｈ、２ｈ、３ｄ、７ｄ５个不同时间点,局部注射海藻氨酸（     

帕金森病大鼠黑质纹状体中氨基酸含量的变化

目的：观察帕金森病大鼠黑质纹状体中氨基酸神经递质的变化。方法：将６－羟多巴胺（６－ＯＨＤＡ）注入鼠右侧黑质内以建立偏侧帕金森病模型,检测其黑质和纹状体中四种氨基酸的含量。结果：帕金森病大鼠损毁侧谷氨酸（Ｇｌｕ）、天门冬氨酸（Ａｓｐ）、甘氨酸（Ｇｌｙ）、和ｒ－氨丁酸（ＧＡＢＡ）的含量较未损毁侧显著增加（Ｐ〈０．０１）。结论：兴奋性氨基酸可能参与了６－ＯＨＤＡ所致的黑质纹状体内神经元损伤。     

6—羟多巴胺损毁的大鼠纹状体内多巴胺排空与左旋千金藤啶碱引起的？…

用高效液相－电化学检测器和旋转计数的方法检测６－羟多巴胺（６－ｈｙｄｒｏｘｙｄｏｐａｍｉｎｅ，６－ＯＨＤＡ）损毁大鼠纹状体多巴胺（ｄｏｐａｍｉｎｅ，ＤＡ）排空与旋转的关系，Ｄ１／Ｄ２混合性激动剂阿扑吗啡（ａｐｏｍｏｒｐｈｉｎｅ，ＡＰＯ，０．２ｍｇ／ｋｇ，ｉｐ）可使３３只大鼠中的２０只出现旋转，其中１５只旋转强度〉５次／分钟，平均为１２．１±５．８次／分钟。Ｄ１选择性激动剂ＳＫＦ３８３９３，Ｄ２选择     

脑源性神经营养因子对帕金森病大鼠黑质多巴胺能神经元的影响

目的 观察脑源性神经营养因子（Ｂｒａｉｎ ｄｅｒｉｖｅｄ－ｎｅｕｒｏｔｒｏｐｈｉｃ ｆａｃｔｏｒ,ＢＤＮＦ）对帕金森病（Ｐａｒｋｉｎｓｏｎｄｉｓｅａｓｅ,ＰＤ）大鼠模型黑质多巴胺能神经元的影响。方法将６－羟基多巴胺用立体定向法注入大鼠一侧中脑黑质制作 ＰＤ大鼠模型,并在注入６－羟基多巴胺之间每天向预伤侧壳核区定位注入ＢＤＮＦ,采用酪氨酸羟化酶免疫组化方法及透射电镜等观察ＢＤＮＦ对黑质多巴胺能神经元的显微超微结构影响。结果　ＢＤＮＦ能改善６－羟基多巴胺造成的ＰＤ大鼠黑质多巴胺能神经元数目减少及超微结构影响。结论　ＢＤＮＦ可减轻６－羟基多巴胺对黑质多巴胺能神经元的毒性作用。     

电针对慢性应激抑郁模型大鼠脑单胺类神经递质的影响

目的　探讨电针刺激百会、印堂穴对慢性应激抑郁模型大鼠脑内单胺类神经递质的影响及治疗抑郁症的机理。方法　将２４ 只ＳｐｒａｇｕｅＤａｗｌｅｙ 雄性大鼠随机分为对照组、抑郁模型组、抑郁模型加电针组和抑郁模型加阿米替林组,每组６ 只。用高效液相电化学法测定大鼠脑内单胺类神经递质及其代谢产物的含量,比较含量的比值。结果　抑郁模型组大鼠脑皮层５羟色胺（５ＨＴ）／５羟吲哚乙酸（５ＨＩＡＡ） 、纹状体多巴胺（ＤＡ）／３,４二羟基苯乙酸（ＤＯＰＡＣ） 分别为０－５０ ±０－１７,１０－３７ ±１－４０,低于对照组（ 分别为０－８８±０－２５ ,１２－３６ ±１－５０）,Ｐ＜ ０－０５ ;皮层去甲肾上腺素（ＮＥ）／５ＨＴ（２－８８ ±１－００） 高于对照组（１－７３±０－４０） ,Ｐ＜ ０－０５。电针刺激百会、印堂穴可使模型大鼠脑皮层５ＨＴ／５ＨＩＡＡ 与ＮＥ／５ＨＴ恢复正常（Ｐ＜０－０５） ,对纹状体ＤＡ／ＤＯＰＡＣ 的降低无影响（ Ｐ＞ ０－０５）。结论　提示电针刺激百会、印堂穴通过降低皮层５ＨＴ的代谢,提高５ＨＴ能神经的活性,并协调ＮＥ 与５ＨＴ之间的平衡来发挥抗抑郁作用。     

帕金森病大鼠模型神经元型一氧化氮合酶(nNOS)阳性神经元的实验研究

目的 观察研究帕金森病(PD)大鼠模型纹状体神经元型一氧化氮合酶(nNOS)阳性神经元，探讨一氧化氮(NO)在PD发病机制中所起作用。方法 应用立体定向技术建立6-OHDA毁损的大鼠PD模型，通过多巴胺受体激动剂阿扑吗啡(APO)测试大鼠旋转行为，免疫组化方法观察黑质酪氨酸羟化酶(TH)阳性神经元和纹状体nNOS阳性神经元的变化。结果 大鼠6-OHDA损毁侧黑质TH阳性神经元数目较对侧明显减少，双侧纹状体nNOS阳性神经元数目无显著差异。结论 6-OHDA对TH阳性神经元有损伤作用，而NOS阳性神经元对其具有抵抗作用。NO可能参与了PD发病机制。     

Co-localisation of NADPH diaphorase activity and GABA immunoreactivity in local circuit neurones in the medial prefrontal cortex (mPFC) of the rat

This study provides evidence that neurones in the medial prefrontal cortex of the rat (mPFC areas 24b, 25, and 32) containing strong NADPH diaphorase reactivity also contain GABA immunoreactivity. Also demonstrated is the co-localisation of NADPH diaphorase activity with immunoreactivity for the neuronal isoform of nitric oxide synthase (nNOS) in mPFC neurones. Qualitative and quantitative analyses in the light and electron microscopes indicate that strongly NADPH diaphorase reactive cells are a subpopulation of GABAergic local circuit neurones and constitute a very small proportion (0.6–1.1%) of neurones in rat mPFC. These results suggest that NADPH diaphorase reactive cells in rat mPFC can influence neural activity via GABA-mediated and NO-mediated mechanisms.     

Changes in the postnatal development on nitric oxide system induced by serotonin depletion

Serotonin (5-HT) is expressed early during central nervous system (CNS) development and plays an important role during this period. Nitric oxide (NO) is also involved in neuronal development. Morphological and functional relationships between NO and 5-HT, demonstrated as alterations of the nitrergic system, were observed after a 5-HT depletion. It has been hypothesized that NO may be related to the neuronal damage induced by some 5-HT neurotoxins. A parachloroamphetamine (PCA) treatment is able to damage ascending 5-HT fibers proceeding from the dorsal raphe nucleus (DRN) and depletes 5-HT storage in neuronal somata. In order to study the effects of a 5-HT depletion on the nitrergic system during postnatal development, Wistar rat pups were injected subcutaneously twice, on postnatal day (PND) 3 and PND4 with PCA. Neuronal nitric oxide synthase (nNOS) immunoreactivity and NADPH diaphorase reactivity were performed on brain sections from PND5, 7, 12, 19, 29 and 62 animals. After the treatment, we found an increased NADPH-d staining and nNOS immunoreactivity in striatum, frontal cortex and hippocampus along the different studied time periods. Interestingly, the expression of both NO markers was higher when 5-HT depletion was more evident, suggesting a very close relationship between 5-HT and NO systems during postnatal development.     

Effects of chronic nicotine administration on nitric oxide synthase expression and activity in rat brain

Although there is substantial evidence concerning the influence of nicotine on nitric oxide (NO) synthesis in the vascular system, there are fewer studies concerning the central nervous system. Although NO metabolites (nitrates/nitrites) increase in several rat brain regions after chronic injection of nicotine, the cellular origin of this rise in NO levels is not known. The aim of the present work was to assess the effects of repetitive nicotine administration on nitric oxide synthase (NOS) expression and activity in male and female rat brains. To determine levels of nitrate/nitrite, the Griess reaction was carried out in tissue micropunched from the frontal cortex, striatum, and accumbens of both male and female rats untreated (naïve) or injected with saline or nicotine (0.4 mg/kg for 15 days). In parallel, coronal sections of fixed brains from equally treated animals were immunostained for neuronal NOS or histochemically labelled for NADPH‐diaphorase activity. Nicotine treatment increased NO metabolites significantly in all brain regions compared with naïve or saline‐treated rats. By contrast, analysis of the planimetric counting of NOS/NADPH‐diaphorase‐positive neurons failed to demonstrate any significant effect of the nicotine treatment. A significant decrease was observed with both techniques employed in saline‐injected female rats compared with naïve animals, suggesting a stress response. The mismatch between the biochemical and the histological data after chronic nicotine treatment is discussed. The up‐regulation of NO sources other than neurons is proposed. © 2002 Wiley‐Liss, Inc.     

Experimental allergic encephalomyelitis in the rat is inhibited by aminoguanidine, an inhibitor of nitric oxide synthase

This study assessed the role of de novo nitric oxide (NO) production in the pathogenesis of experimental allergic encephalomyelitis (EAE) by using aminoguanidine (AG), an inhibitor of nitric oxide synthase (NOS). which preferentially inhibits the cytokine- and endotoxin-inducible isoform of NOS versus the constitutive isoforms consisting of endothelial and neuronal NOS. The maximum clinical severity of EAE and the duration of illness were significantly reduced or totally inhibited by twice daily subcutaneous injection of 100 mg/kg body weight AG. Histochemical staining for NADPH diaphorase, which detects enzymatic activity of NOS, revealed positive reactivity in untreated EAE rats both in parenchymal blood vessel walls and in anterior horn cell neurons, while normal rats and rats with EAE treated with AG showed predominantly the neuronal positivity. Moreover, this NADPH staining pattern was further supported by the immunohistochemical findings that endothelial NOS (eNOS) expression was increased in blood vessels in the inflamed lesions of untreated EAE rats and that inducible NOS (iNOS) was detected in some infiltrating inflammatory cells, while treatment with AG could significantly reduce both iNOS and eNOS production. These results suggest that: (i) both iNOS and eNOS are upregulated in inflamed areas of the rat central nervous system in EAE; (ii) increased NO production plays a role in the development of clinical signs in EAE; and (iii) selective inhibitors of iNOS and/or eNOS may have therapeutic potential for the treatment of certain autoimmune diseases.     

NADPH diaphorase activity and nitric oxide synthase immunoreactivity in lordosis-relevant neurons of the ventromedial hypothalamus

The distribution of the enzymes NADPH diaphorase and nitric oxide synthase in the ventromedial nucleus of the hypothalamus of cycling and ovariectomized/estrogen-treated and control female rats was demonstrated using histochemical and immunocytochemical methods. Serial section analysis of vibratome sections through the entire ventromedial nucleus showed that NADPH diaphorase cellular staining was localized primarily in the ventrolateral subdivision. NADPH diaphorase staining was visible in both neuronal perikarya and processes. Light microscopic immunocytochemistry using affinity-purified polyclonal antibodies to brain nitric oxide synthase revealed a similar pattern of labelling within the ventromedial nucleus and within neurons of the ventrolateral subdivision of the ventromedial nucleus. Control experiments involved omitting the primary antibodies; no labelling was visible under these conditions. Some, but not all, neurons in the ventrolateral subdivision of the ventromedial nucleus contained both NADPH diaphorase and brain nitric oxide synthase as demonstrated by co-localization of these two enzymes in individual cells of this area. That NADPH diaphorase and brain nitric oxide synthase were found in estrogen-binding cells was shown by co-localization of NADPH diaphorase and estrogen receptor and brain nitric oxide synthase and estrogen receptor at the light and ultrastructural levels, respectively. Our studies suggest that brain nitric oxide synthase is present and may be subject to estrogenic influences in lordosis-relevant neurons in the ventrolateral subdivision of the ventromedial nucleus. The hypothalamus is a primary subcortical regulatory center controlling sympathetic function. Therefore, not only is nitric oxide likely to be important for reproductive behavior, but also for the regulation of responses to emotional stress and other autonomic functions.     

Localization of NADPH diaphorase activity in monoaminergic neurons of the rat brain

Nitric oxide has recently been implicated as a neurotransmitter, and may modulate synaptic transmission, cerebral blood flow, and neurotoxicity. NADPH diaphorase histochemistry has been shown to be a reliable marker for nitric oxide synthase, the enzyme that synthesizes nitric oxide, in the nervous system. Because monoaminergic neurons frequently contain co-transmitters, we examined whether these cells also exhibit NADPH diaphorase activity. Frozen sections from postnatal and adult rat brains were stained for NADPH diaphorase activity and either serotonin-like immunoreactivity or tyrosine hydroxylase-like immunoreactivity. Numerous neurons in the mesopontine serotoninergic cell groups (including the caudal linear, dorsal, median, supralemniscal, and pontine raphe nuclei) contained both serotonin-like immunoreactivity and NADPH diaphorase activity. Within the dorsal raphe nucleus, approximately 70% of the serotoninergic neurons in the medial subnuclei displayed NADPH diaphorase activity, while less than 10% of the serotoninergic neurons in the lateral subnuclei were doubly labeled. Retrograde labeling with fluorescent microspheres indicated that many raphe-cortical neurons contained NADPH diaphorase activity. No NADPH diaphorase activity was detected in serotoninergic neurons in the medullary nuclei (including the raphe magnus, raphe pallidum, and raphe obscurus). Only a small proportion of tyrosine hydroxylase-like immunoreactive neurons in the periaqueductal gray, rostral linear nucleus, and rostrtrodorsal ventral tegmental area contained NADPH diaphorase activity. Tyrosine hydroxylase-like immunoreactive neurons in the substantia nigra, locus coeruleus, hypothalamus, olfactory bulb, and dorsal raphe nucleus did not contain detectable NADPH diaphorase activity. The observation that many mesopontine (but not medullary) serotoninergic neurons contain NADPH diaphorase activity suggests that these neurons may release both serotonin and nitric oxide. © Wiley-Liss, Inc.     

Hypovolemia upregulates the expression of neuronal nitric oxide synthase gene in the paraventricular and supraoptic nuclei of rats

We have examined the effects of isotonic hypovolemia on the expression of the neuronal nitric oxide synthase (nNOS) gene in the paraventricular (PVN) and supraoptic nuclei (SON) of the rat, using in situ hybridization histochemistry with a ³⁵S-labelled oligodeoxynucleotide probe complementary to nNOS mRNA. Intraperitoneal (i.p.) administration of polyethylene glycol (PEG) (MW 4000, 20 ml/kg body weight) dissolved in 0.9% saline (20% w/v) induced isotonic hypovolemia. The expression of the nNOS gene in the PVN and SON 6 h after i.p. administration of PEG was increased significantly in comparison with controls. The dual staining for NADPH diaphorase activity and Fos-like immunoreactivity (Fos-LI) showed that at 3 and 6 h after i.p. administration of PEG, a subpopulation of NADPH diaphorase-positive cells in the PVN and SON exhibited nuclear Fos-LI. These results suggest that NO in the PVN and SON may be involved in the neuroendocrine and autonomic responses to non-osmotic hypovolemia.     

Selective upregulation of inducible nitric oxide synthase (iNOS) by lipopolysaccharide (LPS) and cytokines in microglia: in vitro and in vivo studies

A role for free radicals has been proposed in infectious brain disease, where resident microglia cells upregulate the inducible nitric oxide synthase isoform (iNOS), and thus are capable of producing nitric oxide at enhanced rates. Using the constitutively expressed NADPH oxidase, microglial cells can generate superoxide, which reacts with nitric oxide to form the powerful oxidant peroxynitrite. In a mixed cell culture system of astrocytes and microglial cells, nitrite levels, used as an indicator of nitric oxide production, were elevated after the addition of lipopolysaccharide (LPS) and cytokines. Immunohistochemistry and the NADPH diaphorase technique demonstrated selective localization of the iNOS protein in microglial cells, whereas no iNOS protein or NADPH diaphorase activity was detected in astrocytes. A similar cellular distribution was observed in vivo following injection of LPS and cytokines into the rat striatum. By contrast, LPS and interferon-gamma led to translocation of NF-kappaB in microglia and in astrocytes, demonstrating that both cell types are responsive to the stimulus. Therefore, downstream control in iNOS expression is cell type-specific.     

The NO-cGMP Pathway in Neonatal Rat Dorsal Horn

Incubation of slices of neonatal rat spinal cord with nitric oxide donor compounds produced marked elevations in cyclic guanosine 3',5'monophosphate (cGMP) levels. The excitatory amino acid receptor agonists N -methyl- d -aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) produced smaller increases, which were blocked by the nitric oxide synthase (NOS) inhibitor M l - N ^G-nitroarginine (NOArg), indicating that these cGMP responses were mediated by nitric oxide. Immunocytochemistry revealed that, in response to NMDA, cGMP accumulated in a population of small cells and neuropil in laminae II and III of the dorsal horn. This area was also shown, by reduced nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase histochemistry, to contain NOS. These observations suggest that, in the rat spinal cord, NMDA receptor activation is linked to the formation of NO and, hence, of cGMP. This pathway is located selectively in the superficial dorsal horn, consistent with a role in the processing of nociceptive signals.