红藻氨酸诱导癫痫发作小鼠脑组织中NO^—2与硫代巴比妥酸反…

了解活性介质一氧化氮与癫痫发作的关系。用比色法检测红藻氨酸诱导ＢＡＬＢ／ｃ小鼠癫痫发作后，不同时点脑匀浆上清液中亚硝酸根与硫代巴比妥酸反应物的含量。ＮＯ＾－２浓度与ＴＢＡ反应物含量的多少与ＫＡ诱导的癫痫发作时程有关。在发作初期，ＮＯ＾－２随发作持续而增多，但发作后期又迅速减少。ＮＯ＾－２浓度的升高与减低受Ｌ－精氨酸及其硝基衍生物Ｎ＾Ｇ位硝基左型精氨酸的影响。     

L—NAME促进大鼠红藻氨酸诱导性发作

为证明癫痫发作早期一氧化氮（ＮＯ）抗发作效应，用ＮＯ合酶（ＮＯＳ）抑制剂Ｌ－硝基精氨酸甲酯（Ｌ－ＮＡＭＥ）对大鼠红藻氨酸（ＫＡ）诱导性发作进行干预，同时用分光光度法检测海马结构中ＮＯＳ活性的早期变化。发现ＫＡ发作１０ｍｉｎ、３０ｍｉｎ组海马结构中ＮＯＳ活性明显升高，而ＫＡ注射前３０ｍｉｎ给予Ｌ－ＮＡＭＥ可显著抑制ＮＯＳ活性的升高，这种抑制效应与大鼠ＫＡ发作中湿狗样摇动（ＷＤＳ）的提早出现和发生次数增多显著相关。结果提示在ＫＡ诱导大鼠发作早期内源性ＮＯ具有明显的抗发作效用。     

实验性癫痫大鼠海马结构内一氧化氮-环磷酸鸟苷途径的研究

目的研究实验性癫痫发作大鼠海马结构内一氧化氮（ＮＯ）环磷酸鸟苷（ｃＧＭＰ）信使机制及其意义。方法雄性ＳＤ大鼠４１只，随机分为对照组（５只）、红藻氨酸（ＫＡ）１０、３０、６０分钟组（每组６只）和Ｌ硝基精氨酸甲酯（ＬＮＡＭＥ）＋ＫＡ１０、３０、６０分钟组（每组６只）。用放射免疫法测定ＫＡ诱导性癫痫发作中各时点海马结构内ｃＧＭＰ含量及ＬＮＡＭＥ的干预效应。结果ＫＡ注射引起大鼠海马结构内ｃＧＭＰ浓度升高，并加重大鼠癫痫发作（湿狗样摇动提早出现和发生次数增多）；ＫＡ注射前３０分钟给予ＬＮＡＭＥ可明显抑制ＫＡ１０、３０分钟组ｃＧＭＰ浓度的升高，但ＬＮＡＭＥ对ＫＡ６０分钟组ｃＧＭＰ的抑制作用不显著。结论在ＫＡ发作早期，ｃＧＭＰ浓度升高与内源性ＮＯ有关；ＮＯ的抗发作效应可能与ｃＧＭＰ信使机制存在某种联系。     

一氧化氮合酶抑制对戊四氮诱导大鼠点燃模型及该酶阳性神经元的影响

目的：探讨一氧化氮（ＮＯ）在癫痫发病中的作用。方法：ｉｐ４０ｍｇ．ｋｇ＾－１戊四氮３０ｍｉｎ前注射２５ｍｇ．ｋｇ＾－１的Ｎ＾Ｇ－硝基－左旋－精氨酸（Ｌ－ＮＮＡ），连续２２ｄ，观察两组的行为改变及点燃率，同时对３组动物海马，大脑皮质一氧化氮合酶（ＮＯＳ）阳性神经元的变化输入图像扫描仪，对其胞体平均灰度值进行比较。结果：Ｌ－ＮＮＡ可明显抑制戊四氮点燃模型；戊四氮点燃大鼠模型海马，大脑皮质神经元的ＮＯＳ活性显著增高。结论：ＮＯ参与了戊四氮点燃模型的形成。     

NO代谢变化对缺血性脑组织内皮素产生的影响

在兔大脑中动脉阻断（ＭＣＡｏ）型局灶脑缺血前后分别应用外源性一氧化氮合成酶（ＮＯＳ）抑制剂Ｌ－ＮＮＡ和ＮＯ合成底物Ｌ－ａｒｇｉｎｉｎｅ，观察缺血４小时后脑组织内皮素（ＥＴ）含量的变化。结果发现Ｌ－ＮＮＡ组较缺血对照组脑组织ＥＴ含量明显增多（１２６２．９±３８７．６ｖｓ７８９．３±１８８．４ｐｇ／ｍｇ·ｐｒｏ，Ｐ值＜０．０１），脑水肿显著；而Ｌ－ａｒｇｉｎｉｎｅ用药组脑组织ＥＴ含量较缺血对照组明显减少（Ｐ值＜０．０５），且脑水肿减轻。本研究提示ＮＯ能抑制缺血脑组织ＥＴ的产生。ＮＯ对脑缺血影响可能与此途径有关。     

L-NNA减少大鼠脑缺血后脑区NO的生成(论著摘要)

近年来的研究已经肯定了一氧化氮（ＮＯ）参与脑缺血的损伤过程，选择易于透过血脑屏障的ωＮ－硝基左旋精氨酸（Ｌ－ＮＮＡ）并采用不同剂量，观察其对脑缺血时脑区ＮＯ生成的影响。１　材料和方法　雄性ＳＤ大鼠（每组１０只），随机分为假手术组、脑缺血１０ｍｉｎ组、脑缺血１０ｍｉｎ＋Ｌ－ＮＮＡ（０．５ｍｇ／ｋｇ）组、脑缺血１０ｍｉｎ＋Ｌ－ＮＮＡ（１ｍｇ／ｋｇ）组和脑缺血１０ｍｉｎ＋Ｌ－ＮＮＡ（５ｍｇ／ｋｇ）组，实验当日所用的Ｌ－ＮＮＡ按需溶于１ｍＬ生理盐水（ｐＨ７．０），于缺血前３０ｍｉｎ腹腔注射，假手术组用１…     

中枢神经系统一氧化氮对大鼠的痛觉调制作用

以钾离子透入引起大鼠甩尾的电流强度（ｍＡ）作为痛反应指标,采用侧脑室微量注射Ｌ－精氨酸（Ｌ－Ａｒｇ）、亚甲基蓝（ＭＢ）等,大鼠痛阈的变化,分析探讨中枢神经系统中一氧化氮（ＮＯ）对大鼠痛觉的调制作用,结果显示：大鼠侧脑室微量注射ＮＯ前体及供体物质Ｌ－Ａｒｇ和硝普钠（ＳＮＰ）均引起明显的痛敏效应。微量注射ＭＢ和Ｌ－ＮＡＭＥ后大鼠痛阈升高非常显著。侧脑室微量注射ＭＢ和Ｌ－Ａｒｇ混合液后,大鼠痛阈较单纯注     

海人酸致痫动物模型脑内一氧化氮,一氧化氮合酶的变化

目的探讨一氧化氮（ＮＯ）、一氧化氮合酶（ＮＯＳ）在癫痫发生中的作用及ＮＯＳ抑制剂的作用。方法采用海人酸致痫大鼠模型并应用ＮＯＳ抑制剂Ｌ－硝基精氨酸甲酯（Ｌ－ＮＡＭＥ）,分别在致痫后３０分钟、６０分钟取海马组织,匀浆后测定ＮＯ及ＮＯＳ水平。结果致痫３０分钟后海马ＮＯ含量显著升高,至６０分钟恢复正常;ＮＯＳ活性水平增高＞５０％;Ｌ－ＮＡＭＥ明显抑制大鼠的痫性发作,应用ＮＯＳ抑制剂组大鼠海马ＮＯ、ＮＯＳ含量明显下降。结论癫痫发作后脑内ＮＯ、ＮＯＳ活性增强,ＮＯＳ抑制剂通过抑制酶活性使ＮＯ生成降低,并完全抑制痫性发作。ＮＯＳ活性受抑制＞４８％即可产生明显效果。提示ＮＯ可能有内源性致痫作用。     

脑血管病分类亚型与血脂关系的研究

目的：阐明血脂与脑血管病分类亚型的关系。方法：检测了２０８例脑血管病患者血清血脂７项指标含量。并与对照组５０例结果进行比较。ＴＧ、ＴＣ及ＨＤＬ－Ｃ采用酶法测定，ＡＰＯＡ－１、ＡＰＯＢ１００及ＬＰ（ａ）用免疫多点定标法测定，ＬＤＬ－Ｃ由ＴＧ、ＨＤＬ－Ｃ结果按公式计算。结果：脑梗塞（ＣＩ）患者ＴＧ、ＴＣ、ＬＤＬ－Ｃ、ＡＰＯ１００及ＬＰ（ａ）含量显著高于对照组，其ＴＧ、ＡＰＯＢ１００、含量也显著高于脑出血组，且ＬＰ（ａ）与ＡＰＯＢ１００，ＨＤＬ－Ｃ相关，复发ＣＩ亚组ＴＣ、ＬＤＬ－Ｃ、ＡＰＯＢ１００含量，首发及老年ＣＩ亚组ＴＧ、ＴＣ、ＡＰＯＢ１００含量显著高于对照组。结论：血清ＴＧ、ＴＣ、ＬＤＬ－Ｃ、ＡＰＯＢ１００及ＬＰ（ａ）水平升高是ＣＩ的危险因素，其中ＴＣ、ＬＤＬ－Ｃ、ＡＰＯＢ１００对复发ＣＩ危险性大，而首发及老年ＣＩ可能主要与ＴＧ、ＴＣ、ＡＰＯＢ１００有关     

一氧化氮合酶抑制剂对戊四氮诱导大鼠点燃模型及该酶阳性神经元的影响

目的：探讨一氧化氮（ＮＯ）在癫癎 发病中的作用．方法：ｉｐ ４０ｍｇ·ｋｇ－１·ｄ－１戊四氮 ３０ｍｉｎ前注射 ２５ｍｇ·ｋｇ－１的 ＮＧ－硝基－左旋－精氨酸（Ｌ－ＮＮＡ）,连续 ２２ｄ,观察两组的行为改变及点燃串,同时对 ３组动物海马,大脑皮质一氧化氮合酶（ＮＯＳ）阳性神经元的变化输入图像扫描仪,对其胞体平均灰度值进行比较。结果：Ｌ－ＮＮＡ可明显抑制戊四氮点燃模型;戊四氮点燃大鼠模型海马,大脑皮质神经元的ＮＯＳ活性显著增高．结论：ＮＯ参与了戊四氮点燃模型的形成。     

Involvement of nitric oxide in kainic acid-induced excitotoxicity in rat brain

The involvement of nitric oxide (NO) in kainic acid (KA)-induced excitotoxicity was studied in rat brain. With the onset of KA (15 mg kg(-1), s.c.)-induced seizures (convulsions) 30 min after injection, increases in NO, as measured by the formation of citrulline, were seen in cortex (302%), amygdala (171%) and hippocampus (203%). The highest increases were determined 90 min after onset of seizures (120 min after KA injection) with 633%, 314% and 365%, respectively. These changes in NO preceded significant decreases in ATP and phosphocreatine (PCr) ranging from 44 to 53% for ATP and from 40 to 52% for PCr in the respective brain areas. With the exception of the cortex, normal citrulline values were restored within 24 h. Pretreatment with the spin trapping agent N-tert-butyl-alpha-phenylnitrone (PBN, 200 mg kg(-1), i.p.) or the antioxidant vitamin E (Vit-E, 100 mg kg(-1) per day for 3 days) prevented the increase in citrulline and significantly attenuated the loss in ATP and PCr without affecting seizure activity. It is concluded that seizures induced by KA produced a marked increase in the free radical NO, causing oxidative stress and leading to depletion of energy stores. The prevention of the increase in NO and preservation of ATP and PCr levels by PBN and Vit-E suggests the involvement of NO and other related free radicals, such as peroxynitrite (ONOO(-)). The lack of effect of PBN and Vit-E on seizure activity, suggests that NO is not involved in mechanisms regulating KA seizure generation and propagation. PBN and Vit-E or similar compounds may be important protective agents against status epilepticus-induced neuronal degeneration.     

红藻氨酸致痫后大鼠海马ERK、P38 MAPK和JNK的活性变化

目的研究红藻氨酸(KA)诱导大鼠癫痫发作后海马组织细胞外调节蛋白激酶(ERK)、p38MAPK和c-jun氨基末端激酶(JNK)的活性(磷酸化状态)的变化情况。方法立体定向大鼠侧脑室内注射KA引起大鼠癫痫发作,采用Western-blot方法观察KA致痫后大鼠海马中活性ERK、p38MAPK和JNK的变化。结果KA诱导大鼠癫痫发作后,海马组织ERK、p38MAPK和JNK的磷酸化水平开始增高,分别于30min、1h和30min后达高峰,呈对照组的4.76倍、2.16倍和3.95倍,两组比较差异具有显著性(P<0.01),之后逐渐下降。结论KA致痫大鼠癫痫发作后,海马组织MAPKs的活性产生变化,其信号通路可能参与癫痫发作后海马组织的病理生理反应过程。     

一氧化氮对海人酸诱导大鼠癫痫发作脑组织海马结构HSP70表达的影响及意义

目的：研究海人酸诱导大鼠癫痫发作脑组织中一氧化氮（NO）与热休克蛋白70（HSP70）表达的关系。方法：利用免疫印迹分析法（westem blots)观察海人酸诱导大鼠癫痫发作及作用N－硝基－左旋精氨酸（LNNA）干预后脑组织海马结构HSP70的表达。结果：在癫痫发作过程中,预先用LNNA后,HSP70表达量较同一时间未干预的明显低。结论：在癫痫发作过程中,NO对HSP70表达有明显影响。     

The effect of octreotide on kainate-induced wet dog shakes and seizure activity in male and female rats

Systemic kainic acid (KA) administration to rats triggers wet dog shakes (WDS) followed by epileptic seizures. Although WDS are often associated with the occurrence of seizures, we have recently shown that following nitric oxide (NO) synthesis inhibition, the number of WDS decreased; subsequently the onset of seizure activity was shortened, and the number of convulsions was increased. Somatostatin (SS), whose release appears to be controlled by NO, inhibits seizure activity. There are sex differences in seizure susceptibility as well as in SS and NO activities in brain. The present study was undertaken to assess the effect of octreotide (OC), a stable SS analogue, on KA-induced WDS and seizures in rats, with emphasis on possible sex differences. WDS and seizures were induced by KA in male and female (proestrus) Sprague Dawley rats; OC or saline was injected 30 min before KA and the behavior was monitored for 120 min after KA. Octreotide increased the number of WDS and decreased the number of convulsions; this effect was more pronounced in males. Onset of KA-induced seizure activity was earlier in females than males; however, there was no effect of OC on seizure latency. Seizure activity started after the termination of WDS. These results show OC has opposite effects on WDS and convulsions, in that it stimulates the former and inhibits the latter. These results support our previous findings that WDS and seizure activity involve separate mechanisms and suggest that WDS may have an inhibitory effect on limbic seizures.     

THE EFFECT OF OCTREOTIDE ON KAINATE-INDUCED WET DOG SHAKES AND SEIZURE ACTIVITY IN MALE AND FEMALE RATS

Systemic kainic acid (KA) administration to rats triggers wet dog shakes (WDS) followed by epileptic seizures. Although WDS are often associated with the occurrence of seizures, we have recently shown that following nitric oxide (NO) synthesis inhibition, the number of WDS decreased; subsequently the onset of seizure activity was shortened, and the number of convulsions was increased. Somatostatin (SS), whose release appears to be controlled by NO, inhibits seizure activity. There are sex differences in seizure susceptibility as well as in SS and NO activities in brain. The present study was undertaken to assess the effect of octreotide (OC), a stable SS analogue, on KA-induced WDS and seizures in rats, with emphasis on possible sex differences. WDS and seizures were induced by KA in male and female (proestrus) Sprague Dawley rats; OC or saline was injected 30 min before KA and the behavior was monitored for 120 min after KA. Octreotide increased the number of WDS and decreased the number of convulsions; this effect was more pronounced in males. Onset of KA-induced seizure ac tivity was earlier in females than males; however, there was no effect of OC on seizure latency. Seizure activity started after the termination of WDS. These results show OC has opposite effects on WDS and convulsions, in that it stimulates the former and inhibits the latter. These results support our previous findings that WDS and seizure activity involve separate mechanisms and suggest that WDS may have an inhibitory effect on limbic seizures.     

Interictal Behavioral Alterations and Cerebrospinal Fluid Amino Acid Changes in a Chronic Seizure Model of Temporal Lobe Epilepsy

This study extends our previous work in which we described the presence of an interictal behavioral disturbance in a chronic animal model of temporal lobe epilepsy (TLE). In this study, we investigated the cerebrospinal fluid (CSF) neurotransmitter changes underlying the development of chronic recurrent seizures of temporal lobe origin and interictal behavioral disturbance in cats made epileptic after intrahippocampal injection of kainic acid (KA). Using high-performance liquid chromatography, we measured 22 putative neurotransmitter amino acids. After intrahippocampal KA injection, cats developed an initial acute period of intense seizure activity. Cisternal CSF amino acids, which were repeatedly sampled during the acute period through a permanent indwelling cannula, were unchanged apart from a mild elevation in CSF alanine. The high-level seizure activity gradually decreased, and cats entered a chronic epileptic period characterized by recurrent yet intermittent temporal lobe seizures. CSF GABA levels during the chronic epileptic period were significantly decreased. In contrast, CSF levels of other amino acids--alanine, tyrosine, taurine, aspartic acid, and glutamic acid--did not change significantly. Behavioral testing also showed a heightened interictal defensive reactivity during the chronic epileptic period. To the extent that CSF GABA concentration reflects brain GABA concentration, this study suggests that a decrease in brain GABA may contribute both to the epilepsy and interictal emotional lability of animals with a chronic seizure disorder of temporal lobe origin.     

Ovarian steroid modulation of seizure severity and hippocampal cell death after kainic acid treatment

To determine whether maintained estrogen or progesterone levels affect kainic acid (KA) seizure patterns or the susceptibility of hippocampal neurons to death from seizures, ovariectomized Sprague-Dawley rats were implanted with estrogen pellets, 0.1 or 0.5 mg, that generated serum levels of 42.4 +/- 6.6 (mean +/- SEM) and 242.4 +/- 32.6 pg/ml or one to six capsules of progesterone that generated serum levels of 11.00 +/-.72 to 48.62 +/- 9.4 ng/ml. Seven days later, the rats were administered KA (8.5mg/kg, ip) and scored for seizure activity; 96 h later, the rats were killed and their brains processed for localization of neuron nuclear antigen (NeuN), a general neuronal marker. The hippocampus was scored for spread (the number of separate regions showing cell loss), and the area within the CA fields occupied by NeuN immunoreactivity was measured (indicating surviving neurons). Administration of estrogen or progesterone (independent of dose) significantly reduced mortality from KA seizures. Progesterone reduced seizure severity in animals that received one to four implants; compared with controls, no difference in seizure severity was noted for animals with six progesterone implants. The reduced seizures in progesterone-treated animals were accompanied by a reduction in the spread of hippocampal damage (r(2) = 0.87; P < 0.05). Likewise, in progesterone-treated rats, neuron survival and reduction in seizure scores were correlated (r(2) = 0.76; P < 0.0001). Estrogen had no effect on seizure severity (P > 0.05), but reduced both the spread (P < 0.05) and degree of neuronal loss (P < 0.05). Indeed, in the estrogen-treated rats, neuronal death was significantly lower than that observed in progesterone-treated animals with equally severe seizures (P < 0.05). These data are consistent with the hypothesis that progesterone produces its effects by reducing seizures, whereas estrogen has little beneficial effect on seizure behavior but protects the hippocampus from the damage seizures produce.     

Influence of antioxidants on the blood-brain barrier permeability during epileptic seizures.

Pentylenetetrazol-induced seizures in rats lead to the breakdown of the blood-brain barrier. We compared the disruption of the blood-brain barrier during epileptic seizure in untreated rats and in rats treated with vitamin E or selenium. The rats were supplemented with nontoxic doses of sodium selenite (4 pp) in drinking water for 3 months, or vitamin E (70 mg/kg) was given intraperitoneally for 30 min before the pentylenetetrazole injection. Evans-blue was used as a blood-brain barrier tracer and was given intravenously at a dose of 4 ml/kg of a 2% solution. The rats were divided into four experimental groups. Group I: control (n = 24); Group II: pentylenetetrazole-induced seizure (n = 12); Group III: vitamin E injected + seizure (n = 12); Group IV: Selenium supplemented + seizure (n = 12). The rats subjected to epileptic seizures showed Evans-blue albumin extravasations especially in the thalamic nuclei, brainstem, occipital, and frontal cortex. Mean values for Evans-blue dye were found to be 0.28 +/- 0.04 mg % brain tissue in control rats and 1.6 +/- 0.2 mg % brain tissue after epileptic seizures (P < 0.01). The magnitude of distribution of the blood-brain barrier during epileptic seizures was significantly less in rats treated with vitamin E or selenium. The mean value for Evans-blue dye was found to be 1.2 +/- 0.1 mg % brain tissue in selenium supplemented rats and 1.2 +/- 0.1 mg % brain tissue in vitamin E injected rats after epileptic seizures. This difference between treated and untreated animals was found to be significant (P < 0.05). The findings of the present study suggest that free radicals contribute to disruption of the blood-brain barrier during pentylenetetrazol-induced seizures.     

Differential Susceptibility to Seizures Induced by Systemic Kainic Acid Treatment in Mature DBA/2J and C57BLl6J Mice

Summary: Mature DBA/2J (D2) and C57BL/6J (B6) mice aged P.10 weeks were studied to determine susceptibility to behavioral seizures induced by kainic acid (KA) and the possible influence exerted by differences in metabolism and blood-brain barrier (BBB) transport. Mice were observed for 4 h after subcutaneous (s.c.) KA injection. Behavioral seizure parameters included latency to first seizure (clonus), latency to tonic/clonic seizure, and latency to status epilepticus (SE). At a KA dose of 25 mg/kg, 80% of D2 mice exhibited tonicklonic seizures, whereas all B6 mice remained seizure-free. At 30 mg/kg, tonic/ clonic seizures were observed in 100% of D2 mice and 25% of B6 mice. Of D2 mice exhibiting at least one clonic seizure in response to KA at a dose of 25 mg/kg, 50% entered SE and eventually died. Administration of [³H]KA (6.6 × 10⁶dpm) at doses of 25 mg/kg (convulsive) or 11.1 μ/g (nonconvulsive) to mice of both strains resulted in similar levels of radioactivity in cortex, hippocampus, and cerebellum 30 and 60 min after injection. Bioconversion of [³H]KA to a radiolabeled brain metabolite in vivo could not be documented in mice from either strain. Results confirm previously reported differences between D2 and B6 mice in their relative susceptibility to seizures induced by systemic KA administration and suggest that these differences are not related to strain-specific variation in metabolism or BBB transport of KA. Further studies of these two strains of mice may be useful for investigating genetic influences upon seizure susceptibility.