左旋多巴对帕金森病大鼠黑质多巴胺能神经元及纹状体多巴胺递质的影响

目的　研究长期应用左旋多巴对帕金森病 (PD)大鼠黑质多巴胺 (DA)能神经元和DA递质的影响。方法　采用 6 羟基多巴胺 (6 OHDA)制备部分损毁和严重损毁的PD大鼠模型 ,给两种模型口服不同剂量左旋多巴 /苄丝肼 3个月 ,通过观察大鼠旋转行为、酪氨酸羟化酶 (TH)免疫组化染色和高效液相色谱 电化学检测仪 (HPLC ECD)检测纹状体单胺类递质 ,研究左旋多巴对PD大鼠残存的黑质DA能神经元的影响。结果　 (1)左旋多巴对PD大鼠的旋转行为无明显影响 ;(2 )TH阳性细胞数损毁侧 /非损毁侧比值在左旋多巴喂药组和不喂药对照组的差异无显著意义 (P >0 0 5 ) ;(3)在严重损毁组 ,大剂量左旋多巴使PD大鼠损毁侧DA和 3,4二羟基苯乙酸 (DOPAC)水平明显升高(P <0 0 1)。结论　长期使用左旋多巴对 6 OHDA单侧损毁的PD大鼠残存的黑质DA能神经元无毒性作用。     

左旋多巴对体外培养大鼠纹状体的神经毒性及其保护方法的研究

目的 研究左旋多巴（Ｌ－ｄｏｐａ）的神经毒性及其神经保护方法。方法 用胎盼兰染色法检测Ｌ－ｄｏｐａ和抗氧化剂还原型谷胱甘肽（ＧＳＨ）、ＮＭＤＡ受体拮抗剂ＭＫ８０１对体外培养大鼠纹状体的神经元活力的影响。结果 Ｌ－ｄｏｐａ使大鼠纹状体神经元活力明显下降（Ｐ〈０．０１）,ＧＳＨ和ＭＫ８０１可明显减轻Ｌ－ｄｏｐａ引起的纹状体神经元活力下降（Ｐ〈０．０１）。结论 Ｌ－ｄｏｐａ可能通过氧化应激和兴奋ＮＭＤＡ受体两个途径发挥其神经毒性,抗氧化剂或ＮＭＤＡ受体拮抗剂与Ｌ－ｄｏｐａ合用可能减轻Ｌ－ｄｏｐａ的神经毒性。     

不同剂量左旋多巴对帕金森病大鼠行为学影响

目的观察不同剂量左旋多巴治疗帕金森病（PD）的效果,并进一步探讨合理使用左旋多巴治疗PD的剂量。方法采用6-OHDA脑立体定向注射术建立大鼠PD模型,采用行为学观察法观察3种不同剂量左旋多巴[按体重10、50、100mg/（kg.d）]作用不同时间（1、3、5、7d）对PD大鼠黑质细胞毒性作用后的行为学变化以及停止左旋多巴治疗后7d各项指标的变化。结果与对照组比较,小剂量组大鼠旋转圈数随左旋多巴使用剂量和时间增加而减少,中、大剂量组大鼠旋转圈数随左旋多巴使用剂量和时间增加而增加;各组大鼠旋转启动时间随左旋多巴使用剂量和时间增加而减少,最高转速及持续时间则随使用剂量增加而增加。结论应尽可能以小剂量、间隔使用左旋多巴治疗PD。     

左旋多巴治疗对实验性帕金森病大鼠黑质纹状体TNF—a表达的影响

目的　研究左旋多巴 (L - dopa)治疗对实验性帕金森病 (PD)大鼠黑质纹状体肿瘤坏死因子(TNF-α)表达的影响。方法　黑质定位注射 6 -羟多巴胺 (6 - OHDA )制备偏侧 PD大鼠模型 ,经 5 0～ 10 0 mg/ kg体重 L - dopa灌胃治疗 4周后 ,检测双侧额叶皮质、黑质和纹状体区域 TNF-α的表达。结果　 6 - OHDA损毁侧黑质和纹状体 TNF-α含量和阳性细胞面密度分别显著高于健侧 (均 P<0 .0 5 )。损毁侧与健侧 TNF-α含量的比率随 L - dopa治疗用量的增加而增高 ,且均显著高于对照组 (P<0 .0 5 )。结论　 L - dopa治疗进一步加剧了PD大鼠黑质纹状体区域 TNF-α的高表达。     

左旋多巴治疗对实验性帕金森病大鼠黑质纹状体TNF-α表达的影响

目的 研究左旋多巴(L-dopa)治疗对实验性帕金森病(PD)大鼠黑质纹状体肿瘤坏死因子(TNF-α)表达的影响.方法 黑质定位注射6-羟多巴胺(6-OHDA)制备偏侧PD大鼠模型,经50～100 mg/kg体重L-dopa灌胃治疗4周后,检测双侧额叶皮质、黑质和纹状体区域TNF-α的表达.结果 6-OHDA损毁侧黑质和纹状体TNF-α含量和阳性细胞面密度分别显著高于健侧(均P<0.05).损毁侧与健侧TNF-α含量的比率随L-dopa治疗用量的增加而增高,且均显著高于对照组(P<0.05).结论 L-dopa治疗进一步加剧了PD大鼠黑质纹状体区域TNF-α的高表达.     

左旋多巴诱发异动症大鼠纹状体区P38及GAP-43表达的变化

目的　观察帕金森病(Parkinson disease, PD)大鼠经慢性间断性左旋多巴(levodopa,L- dopa)治疗后纹状体区域突触功能的变化。方法　 6 羟多巴胺 (6 OHDA)脑立体定位注射制备偏侧PD大鼠模型,复方L dopa甲酯治疗4周[按体重20 mg/(kg·d),分2次进行腹腔注射]建立异动症(levodopa induced dyskinesias,LID)大鼠模型,采用免疫组化方法检测 PD组和 LID组纹状体内突触素(synaptophysin, P38)及生长相关蛋白(growth associated protein, GAP 43)的表达。结果　 PD 大鼠损毁侧 P38 免疫反应阳性颗粒的数密度[(0. 002 1±0 000. 5)个/μm2]和面密度(0. 045±0.01)均明显高于健侧[分别为(0 .015 0±0. 000 6)个/μm2, (0 027±0 .009)](P<0 .01),GAP- 43阳性颗粒面密度(0. 015±0. 000 3)高于健侧(0. 01±0 .000 27)(P<0. 05);LID大鼠经L dopa治疗后两者表达进一步增多,与PD组大鼠损毁侧相比差异有显著性(均 P<0 .05)。结论　慢性L dopa治疗进一步促进了PD大鼠纹状体区域P38及GAP -43的高表达,可能涉及皮质纹状体病理性长时程增强的突触前机制,提示皮质 纹状体环路的突触可塑性与LID发生密切相关。     

帕金森病大鼠纹状体区乙酰胆碱含量及胆碱酯酶表达的研究

目的观察帕金森病(PD)大鼠纹状体区乙酰胆碱(Acetylcholine,Ach)含量及胆碱酯酶(Ace-tylcholinesterase,AchE)表达的变化。方法采用6-羟基多巴胺(6-OHDA)行脑立体定向术制作大鼠PD模型,用高效液相色谱法(HPLC)测定不同时间点(1、2、3周)及左旋多巴干预后纹状体乙酰胆碱及多巴胺(Dopamine,DA)含量的变化;通过免疫组织化学法观察胆碱酯酶表达的变化。结果患侧纹状体内乙酰胆碱的含量随着时间的延长呈现不同程度的上升(P<0.05)。而多巴胺的含量随着时间的延长有明显的下降(P<0.05),胆碱酯酶的表达在1周有一定的上调,但在2周和3周时呈梯度下降(P<0.05),用药1周后乙酰胆碱的含量稍下降,DA含量和AchE的着色深度有所回升。结论PD大鼠乙酰胆碱的含量明显升高,多巴胺的含量有显著下降;胆碱酯酶的表达以降低为主;使用左旋多巴后乙酰胆碱和多巴胺含量有一定恢复,且胆碱酯酶阳性细胞数有一定回升。     

不同剂量左旋多巴对帕金森病大鼠行为学影响实验研究

目的　观察不同剂量左旋多巴 (L - dopa)治疗帕金森病 (PD)的效果 ,探讨 L - dopa治疗帕金森病的合理方法。方法　通过 6- OHDA脑立体定向注射术建立大鼠 PD模型 ,采用行为学、TUNEL、原位杂交的方法观察左旋多巴小、中、大 3种不同剂量 [10 mg/(kg· d)、5 0 mg/(kg· d)、10 0 mg/(kg· d) ]、不同的作用时间 (1d、3 d、5 d、7d)对 PD大鼠黑质细胞的毒性作用 ,并观察治疗后 7天各项指标的变化。结果　与对照组比较 ,小剂量组大鼠旋转圈数随 L- dopa使用计量和时间增加而减少 ,中、大剂量组相反 ,旋转启动时间随 L- dopa使用剂量和时间增加而加速 ,最高转速及持续时间则相反。结论　我们应尽可能小剂量、间隔使用 L - dopa治疗 PD。     

帕金森病纹状体畸形2例报告并文献复习

帕金森病（Parkinson disease,PD）患者可出现手、足畸形,称为“纹状体畸形”,多发生在帕金森病的中晚期,也可在早期出现。这种畸形与骨关节疾病手足畸形临床表现相似,且部分可伴疼痛不适,但发病率低,文献报道较少,极易被误诊误治。     

慢性左旋多巴治疗对帕金森病大鼠行为及基底节Fos表达的影响

目的：研究帕金森病大鼠左旋多巴诱导异动症模型的行为学特征及其基底节区神经元活性的变化。方法：帕金森病大鼠给予左旋多巴治疗28d，观察其行为学，并用免疫组织化学方法观察纹状体、苍白球区Fos表达情况。结果：慢性左旋多巴治疗后，帕金森病大鼠出现异常不自主运动，包括刻板运动和增加的对侧旋转行为。急性左旋多巴治疗帕金森病大鼠损毁侧尾壳核和苍白球区Fos表达均增加，慢性左旋多巴治疗与急性治疗组比较损毁侧尾壳核区Fos明显减少，而苍白球区表达增加。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是帕金森病患者左旋多巴诱导异动症的啮齿类动物模型，纹状体苍白球神经元活性增强可能参与其发生机制。     

Noradrenergic modulation of the motor response induced by long-term levodopa administration in Parkinsonian rats

A decrease in noradrenergic activity in Parkinson’s disease might play a critical role in long-term motor complications associated with chronic dopaminergic replacement. Using the rat model of parkinsonism with an additional noradrenergic degeneration induced by the N-(-2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4) toxin we evaluated whether the circling motor activity and dose-failure episodes induced by levodopa (l-DOPA) differ between single (6-OHDA) and double (6-OHDA + DSP-4) denervated animals challenged with a single daily dose of l-DOPA. While single-lesioned animals showed a sensitization–desensitization turning response with a significant increase on day 15 and a decrease on day 22, in double-lesioned animals, the turning activity was maximal from day 1 and did not decay on day 22. Double-lesioned rats exhibited significantly higher number of turns on days 15 and 22 and a significantly lower percentage of dose-failure episodes during treatment. Noradrenergic denervation appears to be associated with prolonged long-term dopaminergic sensitization. This type of response appears to be comparable to that in the clinical setting with intermittent l-DOPA administration where no desensitization occurs once the abnormal response is established.     

复方地黄方干预帕金森病药物左旋多巴毒副反应大鼠纹状体多巴胺转运体含量的变化

Long-term application of levodopa (L-3,4-dihydroxyphenylalanine,L-DOPA) for Parkinson’s disease can lead to adverse effects and reduce the amount of dopamine transporter (DAT) in the corpus striatum.The present study attempted to verify whether increasing the amount of DAT can reduce the adverse effects of L-DOPA.The specific radioactive uptake value of DAT in the corpus striatum of the lesioned hemisphere was significantly decreased,but was significantly increased following administration of compound rehmannia formula [Radix rehmanniae preparata (prepared rehmannia root),Concha margaritifera usta (nacre),Radix paeoniae alba (white peony alba),Radix salviae miltiorrhizae (Danshen root),Scorpio (scorpion),green tea] for 4 weeks.The changes in DAT 125I-beta-carbomethoxy-3 beta-(4-iodophenyl) tropane autoradiography were consistent with those in radioactivity.The results revealed that the compound rehmannia formula can reduce the adverse effects of L-DOPA in treating Parkinson’s disease,possibly by increasing the amount of DAT.     

Increase in regional cerebral blood flow of striatum induced by low dose levodopa in a patient with hemiparkinsonism]

A 54-year-old woman was admitted to our hospital because of left-sided rigidity. Neurological examination revealed cogwheel-type rigidity in the left upper and lower limbs without tremor. A brain MRI showed no abnormal findings. She was diagnosed as having left-sided hemiparkinsonism. A 99mTc-ECD SPECT detected a decrease in regional cerebral blood flow (rCBF) in the right corpus striatum. Administration of levodopa/DCI (100 mg/day) improved not only her left-sided rigidity but also the rCBF in the right corpus striatum. The ratio of rCBF in the right corpus striatum to that in the left corpus striatum increased from 96.03% to 99.26% on the three-dimensional stereotactic ROI template. These findings suggest that L-dopa may directly activate the metabolism in the bilateral corpus striatum, and that rCBF in the corpus striatum may be increased indirectly according to the increase of movement in the legs. And also it is suggested that denervation supersensitivity to dopamine may exist in the corpus striatum on the contralateral side of the signs and symptoms in this patient with hemiparkinsonism.     

Effects of prolonged administration of triazolam on adenosine A1 and A2 receptors in the brain of rats

Continuous subcutaneous administration of triazolam, a benzodiazepine with short plasma half-life, for 10 days either decreased (31%, 2 mg/day) or increased (15%, 0.5 mg/day) radioligand binding to adenosine A2 receptors in the rat striatum. In a similar manner, we have shown previously that diazepam (5-10 mg/day), a benzodiazepine with a long plasma half-life attenuated radioligand binding to adenosine A2 receptors in the rat striatum by 45-25%.     

Daily methylphenidate administration attenuates c-fos expression in the striatum of prepubertal rats

Methylphenidate (Ritalin) is a psychostimulant drug used to treat children with attention deficit hyperactivity disorder. Despite its widespread and increasing clinical use, little is known about the long-term consequences of drug treatment. We compared the effects of a single injection of methylphenidate with that of long-term methylphenidate injections (one/day; 14 days) on immediate-early gene expression (c-fos) in the striatum of prepubertal male rats. Rats (25 days old) were injected once daily for 14 days with either saline or methylphenidate (1, 2 or 10 mg/kg), or for 13 days with saline followed by one injection of methylphenidate (1, 2 or 10 mg/kg) on day 14, and were sacrificed 2 h post-injection. Methylphenidate dose-dependently increased FOS immunoreactivity in the striatum. A single injection of methylphenidate (2 or 10 mg/kg) on day 14, following saline treatment for 13 days, caused a dramatic elevation in c-fos expression. This effect was significantly attenuated in animals treated chronically with methylphenidate (2 or 10 mg/kg) for the entire 14 days. Our data suggest that repeated methylphenidate treatment, at a clinically relevant dose (2 mg/kg), markedly inhibits immediate-early gene expression in the brain. This is the first demonstration of methylphenidate-induced modification of gene expression in developing rat striatum and may have implications for chronic methylphenidate use in children.     

Ovariectomy and subchronic estradiol-17 beta administration decrease dopamine D1 and D2 receptors in rat striatum

Ovariectomy and subchronic estradiol-17β cause a down-regulation of dopamine D₁ and, to a lesser extent, D₂ receptors in rat striatum. An intracellular mechanism mediates the DA receptor down-regulation, as various estrogens do not interact with membrane-bound DA receptors in vitro. A common denominator, e.g. enhanced DA turnover, is suggested to mediate the estradiol-induced DA receptor down-regulation. Ovarian factors other than estradiol are additionally proposed to be involved in the regulation of striatal DA receptors.     

Interaction of anandamide with the M(1) and M(4) muscarinic acetylcholine receptors

The M(1) and M(4) muscarinic acetylcholine receptors are the most abundant muscarinic receptor subtypes in the brain, and are involved in learning and memory. Because cannabinoid receptors are also abundantly expressed in similar brain regions and mediate opposite effects to acetylcholine on cognition, the present study investigated whether the endocannabinoid agonist, anandamide, and its metabolically stable derivative, methanandamide, directly modified the binding properties of the human M(1) and M(4) receptors individually expressed in CHO cell membranes. Experiments utilized the antagonists, [(3)H]N-methylscopolamine and [(3)H]quinuclidinyl benzilate. When acetylcholine was used as the inhibiting ligand, shallow, biphasic isotherms were observed at both receptors, characterised by similar apparent dissociation constants for high and low affinity binding at each receptor but with a greater proportion of high affinity sites at the M(4) (40-45%) than at the M(1) receptor (17-20%). In contrast, anandamide and methanandamide inhibited the binding of both radioligands over a narrow (low micromolar) concentration range, with monophasic isotherms characterized by Hill coefficients significantly greater than 1 at both receptors. These effects were not due to the vehicle used. Further saturation binding analyses found anandamide able to significantly reduce the apparent affinity and maximal density of binding sites labeled by [(3)H]quinuclidinyl benzilate. Interestingly, no significant inhibition of radioligand binding was noted using the synthetic cannabinoid agonist, WIN55212-2, or the cannabinoid CB(1) receptor antagonist, SR141716A. These data thus provide evidence for a direct role of anandamides in modulating muscarinic receptor binding properties through a non-competitive mechanism that is unrelated to their actions on cannabinoid receptors.