Mechanism of over-activation in direct pathway mediated by dopamine D_1 receptor in rats with levodopa-induced dyskinesias

1 Introduction The dopamine precursor molecule, 3,4-dihydroxyphe- nyl-L-alanine (levodopa), is currently the most effective pharmacotherapy for Parkinson’s disease (PD). However, long term levodopa treatment is hampered by serious complications, among which the levodopa-induced dyskinesias (LID) can be particularly debilitating. A body of studies have shown that the activation of dopamine D1- mediated direct pathway was related to LID[1]. The level of prodynorphin (PDyn) mRNA has been …     

宫内缺氧及当归注射液干预对幼年大鼠海马齿状回神经元与学习记忆能力的影响

BACKGROUND： The present study analyzed the effect of 3 days （2 h/d） intrauterine hypoxia on learning and memory in juvenile rats, as well as the therapeutic effects of Angelica sinensis on dentate gyrus neurons, as well as learning and memory. OBJECTIVE： To explore the effects of intrauterine hypoxia on hippocampal dentate gyrus neurons, as well as learning and memory, in juvenile rats; to explore N-methyI-D-aspartate receptor-1 （NMDAR1） expression in the dentate gyrus of neonatal rats following intrauterine hypoxia, as well as prolonged hypoxia; to investigate the regulatory mechanisms of Angelica sinensis. DESIGN, TIME AND SETTING： A randomized and controlled experiment based on developmental neurobiology was performed at the Department of Histology and Embryology in Luzhou Medical College from October 2007 to October 2008. MATERIALS： Angelica sinensis solution （250 g/L） was obtained from Central South Hospital of Wuhan University, China. Neuron-specific enolase and NMDAR1 mRNA in situ hybridization reagents were provided by Wuhan Boster Biological Technology, China. Image-Pro Plus 6.0 analysis system was purchased from Media Cybernetics, USA. METHODS： Healthy pregnant Sprague Dawley rats （n = 30） were randomly divided into control （n = 10）, hypoxia （n = 10）, and Angelica （n = 10） groups. The Angelica and hypoxia pregnant rats were placed in a three-gas incubator （oxygen concentration： 13%） starting with day 14 of pregnancy for 2 hours/day for 5 consecutive days to establish a fetal rat intrauterine hypoxia model. One hour prior to modeling, the pregnant rats from the Angelica and hypoxia groups received Angelica sinensis and normal saline （8 mL/kg） injections, respectively, through the caudal vein. The control group procedures were identical to the hypoxia group, but lacked the hypoxic conditions. MAIN OUTCOME MEASURES： Brain tissues of neonatal rats were used to detect expression of NMDAR1 mRNA, and brain tissues of juvenile rats aged 30 days were used to determine neuron-specific enolase mRNA expression by in situ hybridization. Microscopic images （400x） of the hippocampal dentate gyrus were collected. The integral optical density （IOD） value of positive NMDAR1 mRNA cells in the dentate gyrus of neonatal rats, as well as the quantity and the IOD value of positive neuron-specific enolase mRNA cells in the dentate gyrus of juvenile rats, were analyzed with Image-Pro IPP6.0 software. At 30 days after birth, learning and memory parameters were measured in the juvenile rats using Morris water maze. RESULTS： The quantity and the IOD value of positive neuron-specific enolase mRNA cells in the dentate gyrus of the hypoxia group juvenile rats were significantly less than the control group （P 〈 0.05）, and also less than the Angelica group （P 〈 0.05）. The IOD value of positive NMDAR1 mRNA cells in the dentate gyrus of the hypoxia group neonatal rats was significantly greater than the control group, and also greater than the Angelica group （P 〈 0.05）. In the Morris water maze, the searching time during the probe trial and reversal probe trial was shorter in the hypoxia group juvenile rats compared with the control group, and the Angelica group was prolonged compared with the hypoxia group （P 〈 0.05）. CONCLUSION： Intrauterine hypoxia increased expression of NMDAR1 mRNA in the dentate gyrus of neonatal rats, reduced the number of dentate gyrus neurons, and negatively affected learning and memory in juvenile rats. In contrast, Angelica sinensis injection improved the intrauterine hypoxic condition, increased the number of dentate gyrus neurons, and improved the learning and memory deficits of the juvenile rats.     

Effects of dizocipine maleate on mitochondrial ultramicrostructure in neurons following traumatic brain injury in neonatal rats*★ A quantitative time-course analysis

BACKGROUND： The effects of N-methyl-D-aspartic acid （NMDA） receptor antagonist on neurodegeneration in the immature brain following traumatic brain injury （TBI） are still widely unknown. OBJECTIVE： To study the effects of dizocipine maleate （MK-801）, a non-competitive NMDA receptor antagonist, on mitochondrial ultramicrostructure of neurons in the ipsilateral cingulate cortex and hippocampus after TBI in neonatal rats, and to analyze the optimal time interval of MK-801 administration （1 mg/kg）. DESIGN： Completely randomized controlled study.
SETTING： Shanghai Jiao Tong University.
MATERIALS： Eight 7-day-old neonatal SD rats, irrespective of gender, were provided by Experimental Animal Center, Medical College of Fudan University. The experiment was approved by a local ethics committee. MK-801 was provided by Sigma. A CM-120 transmission electron microscope （Philips, Holland） was used for tissue analysis.
METHODS： This study was performed at the Departments of Anatomy, Neuromorphology, and Biophysics, Medical College of Shanghai, Jiaotong University, between October 2006 and January 2007. Focal models of contusion and laceration of brain were established by the free-falling impact method. Eight rats were randomly divided into a normal control group （n = 2 ） and a MK-801 group （n = 6）. Rats in the normal control group did not receive model establishment and administration, and they were only analyzed by an electron microscope. In the MK-801 group, the cingulate cortex was damaged using a contusion device. MK-801 （1 mg/kg） was intraperitoneally injected 30 minutes before lesion, immediately after lesion, and 30 minutes after lesion （n = 2 for each time point）.
MAIN OUTCOME MEASURES： The cingulate cortex and hippocampal tissues from the injured side were removed 24 hours after lesion and routinely processed for analysis of neuronal ultramicrostructure using transmission electron microscopy. RESULTS： Differential therapeutic effects of MK-801 （1 mg/kg） at d     

Intrathecal MK-801 inhibits formalin-induced activation of spinal p38-MAPK in rats**★

BACKGROUND： p38 mitogen-activated protein kinase （MAPK） plays an instrumental role in signal transduction from the cell surface to the nucleus, while subcutaneous injection of formalin can induce increased activation of spinal p38 MAPK. However, the mechanisms underlying the formalin-induced activation of spinal p38 MAPK in rats are unclear. OBJECTIVE： To observe the effects of N-methyl-D-aspartic acid （NMDA） receptor antagonist MK-801 on the formalin-induced activation of spinal p38 MAPK in rats. DESIGN, TIME AND SETTING： This randomized grouping, controlled animal experiment was performed at the Department of Physiology and Neurobiology, Shanxi Medical University between May and November 2007. MATERIALS： Forty eight healthy, adult Wistar rats were randomly divided into two groups： formalin ＋ normal saline （n = 12） and formalin ＋ MK-801 （n = 36）. The formalin ＋ MK-801 group was further divided into three subgroups according to the dosage of MK-801 （10, 50, and 100 nmol/L, 12 rats for each subgroup） METHODS： Following anesthesia, polyethylene tubing filled with sterile normal saline was implanted into the subarachnoid cavity. On postoperative days 5-8, rats received a 15 minute perfusion of normal saline or MK-801 （10, 50, and 100 nmol/L） in the formalin ＋ normal saline and formalin ＋ MK-801 groups, respectively, followed by formalin injection for the induction of nociceptive behavior. MAIN OUTCOME MEASURES： Detection of total p38 MAPK and of phosphorylated p38 MAPK by western Blot analysis; observation of nociceptive behaviors in the 1 hour after formalin injection. RESULTS： Western Blot analysis revealed that injection of formalin had no effect on total p38 MAPK expression but resulted in increased phosphorylation of p38 MAPK in the spinal cord. This increase was apparent after 5 minutes, peaked at 20 minutes, and thereafter descended and reached control levels after 45 minutes. Pretreatment with MK-801 （10, 50, 100 nmol/L） resulted in a dose-dependent reduc     

Effects of mild hypothermia on the expression of microtubule-associated protein 2 in neurons of the hippocampal dentate gyrus in a rat model of cerebral ischemia/reperfusion

BACKGROUND： It is widely accepted that mild hypothermia can protect against injury to cerebral ischemia/reperfusion. OBJECTIVE： To observe the effects of mild hypothermia on microtubule-associated protein 2 （MAP2） expression in the hippocampal dentate gyms in rats following cerebral ischemia/reperfusion. Also, to study neuronal ultrastmctural changes in the dentate gyms to investigate the mechanism of the protection against injury to cerebral ischemia/reperfusion conferred by mild hypothermia. DESIGN, TIME AND SETTING： This randomized grouping, neural cell morphology trial was performed at the Laboratory Animal Center of Yijishan Hospital between March and June 2007. MATERIALS： Eighty-five healthy male Sprague Dawley rats were randomly allocated to three groups： mild hypothermia （n = 40）, normothermia （n = 40）, and sham-operated （n = 5）. METHODS： Cerebral ischemia/reperfusion injury was induced by the suture method in the mild hypothermia and normothermia groups, with a threading depth of 180.5 mm. In the sham-operated group, the suture was inserted 15 mm, with no vascular ligafion, and was followed by reperfusion 2 hours later. In the sham-operated and normothermia groups, the rat rectal temperature was maintained at 36-37 ℃ ; in the mild hypothermia group, it was controlled at 32-33 ℃. MAIN OUTCOME MEASURES： The hippocampal dentate gyms was serially sectioned for hematoxylin-eosin staining and MAP2 immunohistochemistry. Ultrastructural changes and the MAP2 absorbance value of the hippocampal dentate gyms were examined by transmission electron microscopy. RESULTS： The sham-operated group exhibited approximately normal ultrastructure of neurons in the bilateral hippocampal dentate gyms. In the normothermia group, ischemic hippocampal dentate gyms neurons were found with markedly fewer normal mitochondria, greatly proliferated rough endoplasmic reticulum, and a swollen and dysmorphic Golgi. In the mild hypothermia group, at each corresponding time point, these abnormal changes w     

Changes in T .lymphocyte subsets after severe traumatic brain inJury

BACKGROUND： Besides local changes of cranial parenchymal cells, hemorrhage, etc., severe traumatic brain injuries also cause the changes of total body fluid and various functions, and the changes of lymphocytes and T lymphocyte subsets should be paid more attention to. OBJECTIVE： To reveal the changing laws of T lymphocyte subsets after severe traumatic brain injury, and compare with mild to moderate brain injury. DESIGN： A comparative observation. SETTINGS： Department of Neurosurgery, Longgang District Buji People＇s Hospital of Shenzhen City; Central Laboratory of Shenzhen Hospital of Prevention and Cure for Chronic Disease. PARTICIPANTS： All the subjects were selected from the Department of Neurosurgery, Longgang District Buji People＇s Hospital of Shenzhen City from August 2002 to August 2005. Thirty patients with severe brain injury, whose Glasgow coma score （GCS） was ≤ 8 points, were taken as the experimental group, including 21 males and 9 females, aging 16 - 62 years. Meanwhile, 30 patients with mild traumatic brain injury were taken as the control group （GCS ranged 14- 15 points）, including 18 males and 12 females, aging 15 -58 years. All the subjects were in admission at 6 hours after injury, without disease of major organs before injury Informed consents were obtained from all the patients or their relatives. METHODS： （1） The T lymphocytes and the subsets in peripheral blood were detected with immunofluorescent tricolor flow cytometry at l, 3, 7 and 14 days after injury in both groups. （2） The conditions of pulmonary infections were observed at 4 days after injury. The differences of measurement data were compared with the t test. MAIN OUTCOME MEASURES： Changes of T lymphocytes subsets at 1 - 14 days after severe and mild or moderate traumatic injury. RESULTS： Finally, 28 and 25 patients with mild to moderate traumatic brain injury, whereas 25 and 21 patients with severe traumatic brain injury were analyzed at 7 and 14 days respectively, and the missed ones died due to the development of disease. （1） Changes of T lymphocyte subsets： At 1 and 3 days after injury, CD3, CD4, CD8, CD4/CD8 began to decrease, whereas CD8 increased in the experimental group, which were very significantly different from those in the control group （t =2.77 - 3.26, P 〈 0.01）, and began to recover at 7 days, which were significantly different from those in the control group （t = 2.06 - 2.24, P 〈 0.05）, and generally recovered to the normal levels at 14 days （P 〉 0.05）. （2） Conditions of pulmonary infections： At 4 days after injury, the rate of pulmonary infection was significantly different between the experimental group and control group [73% （22/30）, 0, x2=37.29, P 〈 0.01]. CONCLUSION： Patients with severe traumatic brain injury suffer from damages of cellular immune function at early period （within 7 days）, and they are easily to be accompanied by pulmonary infections.     

大鼠伏隔核多巴胺D2受体及转运体与吗啡条件性位置偏爱易感性的关系

Objective To explore the possible role of the expression of dopamine D2 receptor (D2R)and dopamine transporter(DAT)located in the nucleur accumben(Nac)in rats with difierent CPP susceptibility.Methods Altogether 160 male Sprague-Dawley rats were randomly assigned into experiment group(n=130)and control group(n=30).The experiment rats were re-classified into three groups according to the numerical value of the CPP(conditioned place preference),high preference group(HP group,n=26),moderate preference group(n=78)and low preference group(LP group,n=26).At the time of 3 hours,72 hours and 14 days after the final injection,rats in each group were scarified,and the mRNA levels of D2R and DAT in Nac were estimated with in situ hybridization.Results No significant difference of pretest scores staying at the non-preference chamber exist among the three groups(P=0.470),however.the time stayed at the conditioned preference chamber during the test period minus the time stayed at pretest natural preference was significantly higher in the HP group than the LP group(P＜0.01).In each time-point,the expression of D2R mRNA in HP group,were lower that in LP group[(131±3,122±5,119±5)and(125±4,117±8,114±5),P＜0.01].In each time-point,the expression of DAT mRNA in HP group,were significantly lower than that in LP group[(161±5,143±4,134±6)and(156±5,139±3,130±4),P＜0.01].Conclusions It can be inferred that D2R and DAT may be correlated closely and underlie the difierent susceptibility to morphine induced CPP.     

DARPP-32磷酸化状态与左旋多巴诱发异动症形成间关系的研究

目的:研究纹状体区DARPP-32磷酸化水平变化和直接通路活动的改变在左旋多巴诱发的异动症(LID)形成中所起的作用。方法:以SCH23390(D1受体拮抗剂)治疗LID大鼠,观察LID大鼠的行为学改变,并用逆转录聚合酶链反应技术检测LID大鼠纹状体区前强啡肽原(PDyn)基因mRNA的表达情况,免疫印迹技术检测纹状体内DARPP-32蛋白Thr-34位点和Thr-75位点磷酸化修饰水平的变化。结果:LID大鼠纹状体区PDyn mRNA基因表达和磷酸化的Thr-34位点DARPP-32水平较对照组均明显增高,Thr-75位点磷酸化无显著改变。经SCH23390治疗后,LID大鼠异常不自主运动明显减少,PDyn基因表达和Thr-34位点磷酸化水平降低,Thr-75位点磷酸化水平升高。结论:大鼠纹状体区PDyn基因表达和Thr-34位点磷酸化水平的升高与LID的形成有关,提示直接通路活动异常及基底节环路功能异常参与了LID的发生。     

左旋多巴诱导异动症大鼠模型纹状体棘状神经元电活动的研究

目的研究左旋多巴诱导异动症(levodopa induced-dyskinesias LID)大鼠模型纹状体棘状神经元的自发性电活动变化。方法帕金森病(Parkinson disease PD)大鼠模型应用左旋多巴(L-dopa)治疗28d诱发LID大鼠模型,29d L-dopa治疗前15min腹腔注射N-methyl-D-aspartic acid(NMDA)受体拮抗剂地佐环平(MK-801)1次。采用微电极细胞外记录技术检测大鼠模型纹状体棘状神经元的电生理活动。结果LID大鼠纹状体神经元的自发性电活动较对照组(P<0.01)及PD组(P<0.05)明显增多,MK-801治疗后显著减少(P<0.01)。结论纹状体棘状神经元的自发性电活动改变是LID的重要发病机制之一,NMDA受体拮抗剂可能通过逆转纹状体棘状神经元的电活动抑制LID的发生。     

β-arrestin1参与MK-801治疗帕金森病异动症的研究

目的 探讨MK-801缓解帕金森病(PD)异动症的治疗机制。方法 建立PD运动并发症大鼠模型,25只大鼠随机分为3组：异动症(LID)组10只、MK-801处理组10只、PD组5只,另设假手术组5只为对照组。观察MK-801治疗左旋多巴诱导的异动症大鼠模型的行为学变化,并采用免疫组织化学方法和Western blot印迹法检测大鼠纹状体区β-arrestin1的表达情况。结果 MK-801处理后,LID大鼠模型异常不自主运动评分降低和剂峰旋转行为减弱。免疫组织化学结果显示LID组损伤侧β-arrestin1阳性细胞指数[(2.95±0.44) ×104]明显较未损伤侧[(3.78 ±0.37)×104]降低,差异有统计学意义(t =5.415,P＜0.05)。Western blot结果显示,PD模型组损毁侧与未损毁侧纹状体区β-arrestin1含量比值为81.02％ ±2.23％;LID组(64.88％±3.10％)蛋白表达量进一步减少,与PD组比较,差异有统计学意义(t=9.47,P＜0.01);而MK-801组蛋白表达量增高至89.26％±1.90％,与LID组相比,差异有统计学意义(t=14.82,P＜0.01)。结论 MK-801能缓解LID大鼠的行为学变化,其机制可能与β-arrestin1表达增多抑制了谷氨酸受体的过度活化有关。     

多巴胺D1和谷氨酸NMDA受体参与调控异动症大鼠纹状体△FosB蛋白的表达

目的研究多巴胺D1和D2受体以及谷氨酸NMDA受体对△FosB蛋白表达水平的影响,由此探讨它们在左旋多巴诱导的异动症(Levodopa-induced Dyskinesia,LID)发病机制中的作用。方法对单侧黑质纹状体6-羟多巴胺(6-OHDA)损毁致帕金森病(PD)大鼠给予左旋多巴治疗28d制作LID模型,将大鼠分为7组:正常对照组、PD组、LID组、SCH23390治疗组、MK-801治疗组、raclopride治疗组和非LID组,分别观察各组行为学改变并进行异常不自主运动(abnormal involuntary movement,AI M)评分,用免疫组化和免疫印迹方法测定各组△FosB蛋白表达水平。结果多巴胺D1受体阻断剂SCH23390和谷氨酸NMDA受体阻断剂MK-801明显减轻LID大鼠行为学异常,而多巴胺D2受体阻断剂raclopride对异常不自主运动无明显影响;LID大鼠损毁侧纹状体△FosB蛋白表达较PD大鼠和非LID大鼠明显增加;与LID大鼠相比,MK-801和SCH23390均使△FosB蛋白表达显著下降,而raclopride没有这种效应;各组大鼠健侧纹状体△FosB蛋白表达水平没有显著差异。结论多巴胺D1受体和谷氨酸NMDA受体均通过参与调控纹状体△FosB蛋白的表达而影响大鼠LID的发生。     

左旋多巴诱发异动症大鼠模型纹状体神经元可塑性的研究

目的 研究左旋多巴诱发异动症(LID)大鼠模型纹状体区FosB和特异性神经肽基因表达的变化，探讨LID时纹状体神经元的可塑性。方法 分别用免疫组织化学方法和逆转录聚合酶链反应技术(RT-PCR)检测大鼠纹状体区FosB和前脑啡肽原(PPE)及前强啡肽原(PDyn)基因的表达情况。用辣根过氧化物酶(HRP)逆行示踪与免疫组织化学相结合的双重反应技术观测FosB的细胞分布状况。结果 帕金森病(PD)大鼠较正常大鼠损毁侧纹状体PPE mRNA表达明显增多而PDyn mRNA表达减少。LID大鼠较PD大鼠PPE mRNA无明显增多，但PDyn mRNA显著性增多。LID大鼠损毁侧纹状体区FosB阳性神经元明显增多，并且主要分布于纹状体黑质神经元内。结论 纹状体黑质神经元内即早基因FosB及其下游靶基因强啡肽的表达异常与大鼠LID的发生有关，表明LID的发生与直接通路的活动异常密切相关。     

左旋多巴诱导帕金森病异动症与纹状体DARPP-32磷酸化的关系

目的观察帕金森病(PD)异动症(LID)大鼠模型纹状体区多巴胺和环磷腺苷调节的磷酸化蛋白-32(DARPP-32)蛋白Thr75位点磷酸化表达数量及表达位点的改变。方法给予PD大鼠模型左旋多巴治疗21d,评估大鼠行为学变化;采用免疫荧光和Western blot检测大鼠纹状体区DARPP-32蛋白Thr75位点磷酸化表达数量和表达部位的改变情况。结果 PD大鼠长期使用左旋多巴出现类似于人类LID行为学表现。免疫荧光结果显示PD组和LID组大鼠损伤侧DARPP-32(Thr75)的表达多位于强啡肽阳性神经元。Western blot结果显示PD组大鼠损伤侧DARPP-32(Thr75)表达为(159.90±7.22)%,与假手术组比较升高(P<0.05);LID组大鼠损伤侧纹状体DARPP-32(Thr75)的表达为(52.60±4.45)%,与假手术组和PD组比较降低(P<0.05)。结论纹状体黑质投射神经元内DARPP-32蛋白Thr75位点磷酸化表达的改变可能参与了LID的发病。     

DARPP-32磷酸化参与天芪平颤颗粒缓解帕金森病运动并发症的发生

目的研究天芪平颤颗粒对帕金森病(PD)运动并发症大鼠异常不自主行为学及纹状体DARPP-32(Thr75)磷酸化表达的影响,探讨长期左旋多巴使用后天芪平颤颗粒对异动症(LID)的作用机制。方法 6-羟基多巴胺(6-OHDA)制备PD大鼠模型并给予左旋多巴治疗4周,制备LID大鼠模型,将LID大鼠随机分为5组,分别给予大鼠生理盐水(LID模型组)、左旋多巴(西药组)以及小、中、大剂量天芪平颤颗粒组,另设假手术组(n=5)为对照组,并用免疫组化和Western blotting法观察各组大鼠纹状体内磷酸化DARPP-32(Thr75)的表达情况。结果长期使用左旋多巴后,PD大鼠出现刻板运动和进行性增加的对侧旋转等行为学改变。天芪平颤颗粒可明显缓解LID大鼠的不自主运动行为。免疫组化结果显示,西药组磷酸化DARPP-32(THr75)表达较LID模型组降低〔(3.53±0.20)×104 vs.(3.85±0.30)×104,P<0.05〕,大、中、小剂量中药组磷酸化DARPP-32(THr75)表达量分别为(8.54±0.17)×104、(8.10±0.31)×104、(7.06±0.69)×104,较西药组升高(P<0.05)。Western blotting结果与免疫组化基本一致,西药组磷酸化DARPP-32(THr75)灰度值与LID模型组比较无统计学差异〔(0.97±0.24)×106 vs.(1.08±0.12)×106,P>0.05〕,大、中、小剂量中药组大鼠纹状体磷酸化DARPP-32(THr75)灰度值分别为(2.40±0.09)×106、(2.37±0.16)×106、(1.44±0.14)×106,较西药组升高(P<0.05)。结论天芪平颤颗粒可降低LID大鼠的异常不自主运动评分,其机制可能是通过逆转磷酸化DARPP-32(THr75)表达的进一步下降,从而抑制了PKA通路的过度活化;DARPP-32磷酸化参与了治疗PD运动并发症的机制。     

左旋多巴诱发异动症大鼠模型黑质网状部电活动的研究

目的:研究左旋多巴诱发异动症(LID)大鼠模型基底节输出核黑质网状部(SNr)电活动的改变。方法:将记录电极立体定位插入大鼠损毁侧SNr,使用脑电图仪分别记录正常组、非LID组、LID组和MK801+LID组注射左旋多巴前后SNr电活动。结果:用药前,与正常组比较其余三组SNr脑电图波频均明显降低(P<0.05)。用药后,与用药前比较正常组波频无明显降低(P>0.05),非LID组和LID组波频无明显变化(P>0.05)。MK801+LID组大鼠刻板动作明显减少,SNr脑电图波频较LID组增加(P<0.05),与正常组比较无显著性差异(P>0.05)。LID组可见到间断少量的高大波,类似于异常放电波。其余三组未见波形改变。结论:SNr神经元异常放电与LID的发生有关,干预SNr神经元异常电活动可以抑制LID的发生。     

MK-801对左旋多巴诱导异动症大鼠模型基底节区神经元活性的影响

目的:研究NMDA(N-methyl-D-aspartate)受体拮抗剂MK-801对左旋多巴诱导的帕金森病大鼠异常不自主运动行为学及其基底节区Fos表达的影响,探讨谷氨酸对长期左旋多巴治疗后帕金森病大鼠基底节输出通路活性改变的影响。方法:帕金森病大鼠给予左旋多巴治疗28d,第29d左旋多巴治疗前15min腹腔注射MK-801一次。观察其行为学变化,并用免疫组织化学方法观察尾壳核和苍白球Fos表达情况。结果:长期间断左旋多巴治疗后,帕金森病大鼠出现刻板运动和进行性增加的对侧旋转等行为学改变。提前用MK-801抑制了其刻板动作,而增加了对侧旋转行为。与左旋多巴治疗组比较,MK-80l治疗组损毁侧尾壳核区Fos表达明显增多而苍白球区Fos表达明显减少。结论:慢性间断性左旋多巴治疗诱导帕金森病大鼠异常不自主运动和旋转期缩短是帕金森病患者左旋多巴诱导异动症和疗效减退的啮齿类动物模型,谷氨酸在其发生机制中发挥重要作用,NMDA受体拮抗剂可能通过逆转直接通路的活动而抑制异动症和疗效减退的发生。     

可控释左旋多巴和苄丝肼微球减少帕金森病大鼠异动症的发生

目的 观察聚乳酸-羟基乙酸共聚物( PLGA)包裹的可释放左旋多巴和苄丝肼的微球对帕金森病(PD)大鼠运动症状及异动症发生的影响并探讨其机制.方法 PLGA包裹左旋多巴及苄丝肼制作微球,高效液相法测定微球在体内释放出的左旋多巴和苄丝肼的浓度,6-羟基多巴胺(6-OHDA)注射制作PD大鼠模型,制模成功的PD大鼠随机分成PD组、左旋多巴组、微球组(每组12只),另设溶剂注射假手术组(n=12).左旋多巴组和微球组大鼠分别接受左旋多巴和苄丝肼(左旋多巴12 mg/kg,苄丝肼15 mg/kg)或等剂量微球皮下注射,在治疗的第1、4、7、10、14天行大鼠前肢功能测定,治疗2周后行大鼠异常不自主运动( AIM)评分,免疫组织化学及Western blot法检测纹状体区磷酸化的多巴胺和环磷腺苷调节的磷酸化蛋白-32(DARPP-32)(Thr34)和△FosB水平.结果 体内释放实验表明第7天时左旋多巴和苄丝肼释放量分别达76.2％和83.6％.微球处理组大鼠在治疗的第10天和第14天时前肢跨步数分别为5.8±1.6和5.2±1.5,比左旋多巴组(2.4±1.1、1.2±0.5)明显增加(t =4.12,5.43,均P＜0.01).微球处理组大鼠第14天AIM评分[(16.0±2.1)分]较左旋多巴处理组[(26.0±3.2)分]显著下降,差异有统计学意义(t =6.59,P＜0.01).免疫组织化学显示微球处理组大鼠纹状体磷酸化DARPP-32水平[(3.7±1.3)×104]较左旋多巴处理组[(7.9±2.2)×104]明显降低(t=2.95,P＜0.05).Western blot结果显示微球处理组大鼠磷酸化DARPP-32和△FosB水平分别为119.4％±11.3％和149.3％±12.3％,较左旋多巴组(184.8％±13.7％和300.4％±14.2％)显著下降(t =4.12、2.91,均P＜0.05).结论 微球皮下注射可以改善PD大鼠的运动症状,同时可以减少PD大鼠异动症的发生,这与微球释放的左旋多巴持续性刺激PD大鼠从而减少磷酸化DARPP-32和△FosB的水平有关.