氨甲酰胆碱对多巴胺诱导的小脑颗粒细胞凋亡的保护机制

【目的】研究多巴胺诱导小脑颗粒神经元凋亡的分子机制,以及胆碱受体激动剂氨甲酰胆碱对多巴胺诱导凋亡的作用。【方法】在培养的小脑颗粒神经元建立多巴胺凋亡模型。用相差显微镜观察形态学,DNA凝胶电泳和Hoechst33258核染色分析神经元凋亡,细胞的存活率用二乙酸荧光素（FDA）染色法检测。采用Westernblot分析细胞外信号调控的蛋白激酶（ERK）激活情况。【结果】多巴胺可诱导小脑颗粒神经元凋亡,并可持续激活ERK,二者均可被氨甲酰胆碱和PD98059抑制。氨甲酰胆碱对神经元的保护作用及对ERK激活的抑制作用可被阿托品阻断。【结论】多巴胺在小脑颗粒神经元诱导凋亡可能是通过持续激活ERK介导的。氨甲酰胆碱通过激活M胆碱受体,继而抑制了ERK的激活,从而起到对神经元的保护作用。     

原发性高血压患者红细胞[Ca2+]i浓度变化及影响因素

目的：观察原发性高血压患者红细胞[Ca^2 ]i,多巴胺β羟化酶及ATP含量变化并分析其结果。方法：测定35例高血压患者的红细[Ca^2 ]i、ATP、血清多巴胺β羟化酶活性,血糖及血浆胰岛素含量,并以30例健康成年人为对照。结果：高血压患者的红细胞[Ca^2 ]i、ATP、多巴胺β羟化酶均明显高于对照组（P＜0．05,P＜0．01）,但血糖与胰岛素未见明显变化。结论：高血压患者血清多巴胺β羟化酶活性增强伴随ATP与[Ca^2 ]i升高。     

大鼠心肌多巴胺受体在缺氧-复氧时的表达变化及其意义

目的： 观察大鼠心肌多巴胺受体在缺氧-复氧时的表达，初步探讨其与心肌缺氧-复氧损伤的关系。方法: 采用Langendorff离体灌流装置复制大鼠心肌缺氧-复氧模型。用RT-PCR和Western blotting结合图像分析系统，分别检测缺氧-复氧心肌多巴胺受体DR1、DR2 mRNA和蛋白质的表达变化；用紫外分光光度计测定大鼠冠脉流出液中LDH活性；透射电镜观察心肌超微结构的变化。结果: 大鼠心肌组织在缺氧40 min时的DR1、DR2 mRNA和蛋白表达高于正常对照组(P<0.05)，缺氧40 min后复氧1h显著高于正常对照组(P<0.01)，2 h达高峰，3 h、4 h后降低，但仍高于正常组(P<0.01)；同时随复氧时间延长，冠脉流出液中LDH活性增加，心肌超微结构损伤加重。结论: 大鼠心肌多巴胺受体DR1、DR2表达在缺氧-复氧过程中呈先升高后降低的特点，可能参与心肌缺氧-复氧损伤的发生。     

Effects of various direct or indirect dopamine agonists on the latency of the acoustic startle response in rats

Summary The effects of dopamine agonists were investigated on the latency of the acoustic startle response in male Wistar rats. Four indirect dopamine agonits were tested: GBR 12783 (5–20mg/kg), BTCP (5–20mg/kg), dexamphetamine (3–6mg/kg) and L-DOPA 100 mg/kg associated with benserazide 25 mg/kg; they induced an increase in startle latency. Apomorphine at a dose (50 g/kg) known to decrease dopaminergic transmissions, was ineffective on the startle response. On the contrary, at 0.6 or 2 mg/kg, apomorphine induced an increase in the startle latency. A similar effect was observed with bromocriptine at 10 mg/kg from the 10th min up to at least the 9th hour after treatment. The specific agonist of D2 receptors Ru 24926 (0.45 mg/kg) enhanced the startle latency as well as the specific agonist of D1 receptors SKF 38393 (10 mg/kg). The association of these drugs resulted in an apparent additivity of their individual effects. The effect of apomorphine (0.6 mg/kg) was only partially reduced by a high dose of the specific D2 antagonist amisulpride (80 mg/kg) and more clearly antagonized by the specific D1 antagonist SCH 23390 (50 g/kg). It is concluded that D2 and D1 receptors contribute to the increase in startle latency elicited by direct or indirect dopamine agonists.     

多巴胺对兔实验性形觉剥夺性近视形成的影响

目的　研究多巴胺对实验性近视形成的影响.方法　7日龄幼兔52只,分A,B,C,3组.A组20只,单纯缝合眼睑;B组16只,缝合眼睑+玻璃体内注射多巴胺;C组16只,缝合眼睑+玻璃体注射生理盐水.均以右眼为实验眼,左眼为对照眼.第60日用A超测量每组双眼的前房深度、晶体厚度、玻璃体腔长度和眼轴长度,并计算玻璃体腔长度／眼轴长度,同时进行病理学观察.结果　A,C两组中实验眼的玻璃体腔长度、眼轴长度和玻璃体腔长度／眼轴长度分别为(7.9±0.6)mm,(15.4±0.6)mm,0.52±0.03;(7.3±0.5)mm,(15.1±0.7)mm,0.49±0.02;对照眼则为(7.2±0.8)mm,(14.5±0.7)mm,0.48±0.02;(6.8±0.4)mm,(14.6±0.6)mm,0.46±0.02.两眼间的差异有高度显著的统计学意义(P<0.001),前房深度和晶体厚度无统计学差异,而B组均无统计学差异.巩膜胶原纤维在A,C两组中明显变细,而在B组中改变较轻.结论　形觉剥夺能导致眼球的轴性延长,玻璃体腔延长和VCL/AL增大是其形态学原因,巩膜纤维的变细、延长是其病理学原因之一,而多巴胺能部分阻止这些改变.     

多巴胺诱导PC12细胞凋亡的免疫组织化学及超微结构分析

目的 研究帕金森病（PD）多巴胺能神经元的死亡机制,方法在免疫组织化学基础上,采用流式细胞仪,电泳及电镜技术观察不同浓度多巴胺（DA）诱导大鼠嗜铬细胞瘤PC12细胞凋亡的超微结构及生化改变。结果 适当浓度DA可诱导PC12细胞凋亡,早期表现为线粒体结构及功能的改变并有抗凋亡蛋白bcl-2的达,后期电镜下可见亡特征性核结构改变及典型的DNA阶梯状电泳带,结论 细胞凋亡参与了PD的病变过程,线粒体在早期细胞凋亡中起着重要的调节作用。     

多巴胺D2受体基因启动子A-241G多态性在精神分裂症家系中的连锁不平衡传递

目的:探讨多巴胺D2受体基因(dopamine D2 receptor,DRD2)启动子A-241G多态性与精神分裂症的关系.方法:采集101个家系,每家有2名或2名以上符合ICD-10精神分裂症诊断标准患病同胞且父母存活.对DRD2启动子的A-241G多态性进行检测.结果:(1)DRD2启动子的A-241G等位基因频度和基因型频度在父母组、非患病同胞组和患病同胞组之间差异无显著性,在3组不同性别之间以及在精神分裂症不同亚型之间基因型频度和等位基因频度的分布差异亦无显著性;(2) 传递不平衡检验发现在患病同胞(χ2 =0.94,P>0.05,OR=0.83,95%可信区间0.57～1.21)中未表现传递不平衡性,而在非患病同胞(χ2 =6.76,P<0.01,OR=3.17,95%可信区间0.41～24.71)中存在传递不平衡性,其中-241A等位基因在非患病同胞中传递较多;(3) 基因型与妄想总分、幻觉总分、思维形式障碍、情感障碍、精神性失语及症状持续时间等临床特征相关.结论:DRD2启动子的A-241G多态性对精神分裂症的发病和临床表现具有一定影响.     

缺氧缺血性新生大鼠脑组织内多巴胺含量的动态变化

目的　观察缺氧缺血性脑损伤 (Hypoxic-ischemicbraindamage ,HIBD)后不同时间大脑皮层、纹状体、脑干内多巴胺 (Dopamine,DA)含量的动态变化 ,探讨DA在HIBD中的变化规律。方法　 7日龄SD大鼠 99只 ,采用阻断左侧颈总动脉后置于含 8%O2 的低氧环境中 ,建立HIBD动物模型。用高效液相-电化学检测法 (HPLC -ECD)测定脑损伤后 0h、0 .5h、1h、3h、6h、9h、12h、2 4h、48h不同时间皮层、纹状体和脑干内多巴胺DA含量的动态变化。结果　动物缺氧缺血 (Hypoxic -ischemic,HI)后多巴胺在 0 .5h即有明显上升 ,6h时纹状体内DA含量达到高峰 ;9h大脑皮层和脑干达峰值 ,之后缓慢下降。结论　新生鼠缺氧缺血后脑细胞内多巴胺含量变化有一定的规律 ,各脑区变化情况有差别。     

肝素钠软膏对多巴胺诱发兔静脉及其周围组织损伤治疗的实验研究

目的：笔者观察了肝素钠软膏、５０％硫酸镁、透明质酸酶对多巴胺诱发兔静脉及其周围组织损伤的治疗作用。方法：兔耳静脉连续注身大剂量的多巴胺和静脉周围组织注射多巴胺诱发静脉炎。结果：５０％硫酸镁加肝素钠软膏对多巴胺诱发的静脉炎治疗效果最好,其次为肝素钠软膏和５０％硫酸镁,透明质酸酶无治疗作用。     

Catecholamine modulatory effects of nepicastat (RS-25560-197), a novel,potent and selective inhibitor of dopamine-β-hydroxylase

1. Inhibitory modulation of sympathetic nerve function may have a favourable impact on the progression of congestive heart failure. Nepicastat is a novel inhibitor of dopamine-β-hydroxylase, the enzyme which catalyses the conversion of dopamine to noradrenaline in sympathetic nerves. The in vitro pharmacology and in vivo catecholamine modulatory effects of nepicastat were investigated in the present study.
2. Nepicastat produced concentration-dependent inhibition of bovine (IC₅₀=8.5±0.8 nM) and human (IC₅₀=9.0±0.8  nM)dopamine-β-hydroxylase. The corresponding R-enantiomer (RS-25560-198) was approximately 2–3 fold less potent than nepicastat. Nepicastat had negligible affinity (>10 μM) for twelve other enzymes and thirteen neurotransmitter receptors.
3. Administration of nepicastat to spontaneously hypertensive rats (SHRs) (three consecutive doses of either 3, 10, 30 or 100 mg kg⁻¹, p.o.; 12 h apart) or beagle dogs (0.05, 0.5, 1.5 or 5 mg kg⁻¹, p.o.; b.i.d., for 5 days) produced dose-dependent decreases in noradrenaline content, increases in dopamine content and increases in dopamine/noradrenaline ratio in the artery (mesenteric or renal), left ventricle and cerebral cortex. At the highest dose studied, the decreases in tissue noradrenaline were 47%, 35% and 42% (in SHRs) and 88%, 91% and 96% (in dogs) in the artery, left ventricle and cerebral cortex, respectively. When tested at 30 mg kg⁻¹, p.o., in SHRs, nepicastat produced significantly greater changes in noradrenaline and dopamine content, as compared to the R-enantiomer (RS-25560-198), in the mesenteric artery and left ventricle.
4. Administration of nepicastat (2 mg kg⁻¹, b.i.d, p.o.) to beagle dogs for 15 days produced significant decreases in plasma concentrations of noradrenaline and increases in plasma concentrations of dopamine and dopamine/noradrenaline ratio. The peak reduction (52%) in plasma concentration of noradrenaline and the peak increase (646%) in plasma concentration of dopamine were observed on day-6 and day-7 of dosing, respectively.
5. The findings of this study suggest that nepicastat is a potent, selective and orally active inhibitor of dopamine-β-hydroxylase which produces gradual modulation of the sympathetic nervous system by inhibiting the biosynthesis of noradrenaline. This drug may, therefore, be of value in the treatment of cardiovascular disorders associated with over-activation of the sympathetic nervous system, such as congestive heart failure.