Difference in in vivo receptor binding between [3 H]N-methylspiperone and [3 H]raclopride in reserpine-treated mouse brain

Summary The in vivo binding of [³ H]N-methylspiperone (NMSP) and [³ H]raclopride was compared in mice treated with reserpine (5 mg/kg, 24 hr prior to the tracer injection). With both radioligands, selective accumulation of radioactivity in the striatum following intravenous injection was observed, whereas a relatively low accumulation and a rapid decline in radioactivity in the cerebellum was seen. Reserpine significantly decreased [³ H]NMSP binding in vivo, however it increased [³ H]raclopride binding. By compartment model analysis, it was found that the decrease in [³ H]NMSP binding was primarily due to the decrease in the association rate (K3) and the increase in [³ H]raclopride was due to the decrease in the dissociation rate (K4) in vivo. As both Kd and Bmax of dopamine D2 receptors have been reported to be unaltered by reserpine, these results suggested that some unknown factors except Kd and Bmax which influence on in vivo binding of receptors might be changed by reserpine. These results revealed that it is of importance to measure kinetics of ligand-receptor binding in vivo rather than static analysis. These two different types of radioligands can be combined to reveal functional roles of dopamine receptor in vivo, especially in the study of the human brain with positron emission tomography (PET).     

Drug-induced changes in catecholaminergic cells of the fish retina

The changes in fluorescence intensity and number of visible catecholaminergic cells (CA-cells), as revealed by means of a histofluorescence technique, were used as indicators of the effects of various pharmacological agents upon CA-cells in the retina of fishes (Cyprinus carpio and Eugerres plumieri). The study includes in vivo and in vitro experiments. In the in vivo experiments, intravitreal injection, two or three hours before eye enucleation, of 10 microgram L-DOPA, dopamine, or noradrenaline accentuated CA-cell fluorescence and increased the number of visible cells, whereas 10 microgram of tyramine, octopamine, synephrine, or adrenaline reduced the endogenous fluorescence. Intramuscular injection of reserpine (3 mg/kg) abolished CA-cell fluorescence. In the in vitro experiments, pieces of isolated retinas were incubated for three or 30 minutes in media containing different drugs. Only minor changes in fluorescence were detected after three minutes of incubation, but after 30 minutes, dopamine (20 microM) markedly enhanced CA-cell fluorescence. Carbachol (20 mM), acetylcholine (10 mM) plus BW-anticholinesterase (1 mM) or substance P(1.6 x 10(-2) mM), all reduced CA-cell fluorescence. Kainic acid (20 mM) abolished fluorescence from CA-cell somata, while fluorescent fiber networks remain unchanged. L-aspartate (5 mM) and GABA (10 mM) in the incubation medium did not influence fluorescence intensity. The results are relevant to, and consistent with, electrophysiological observations of dopamine-mediated spatial effects on horizontal cell potentials.     

EFFECT OF RESERPINE ON RELAXANT RESPONSES OF CANINE FEMORAL ARTERIAL STRIPS

1 We studied relaxant responses to adenosine, glyceryl trinitrate, and hydralazine in control (n = 5) and reserpine pretreated (1 mg/kg i.m., 24 h prior; n = 5) canine femoral arterial strips contracted with noradrenaline. 2 Reserpine did not alter contractile responses to noradrenaline. 3 Reserpine pretreated tissues were supersensitive to glyceryl trinitrate, but not to adenosine or hydralazine.     

利血平诱导的急性抑郁模型大鼠体内CYP450亚酶的活性变化

目的:运用Cocktail探针法测定利血平诱导的急性抑郁模型大鼠体内6种细胞色素P450(CYP450)亚酶活性变化,从药物代谢相互作用的角度探寻抑郁症的发病机制。方法:建立利血平诱导的急性抑郁模型,大鼠随机分为空白组(记为A组),模型组(记为C组)和西药文拉法辛组(记为H组),适应1星期后,H组连续给药2周,A组和C组给予清水2周,第21天C组和H组按4 mg·kg~(-1)腹腔注射利血平注射剂,A组注射等体积生理盐水,第22天禁食不禁水12 h,第23天各组大鼠按10 m L·kg~(-1)灌胃给予混合探针药物。选取茶碱、氯唑沙宗、甲苯磺丁脲、右美沙芬、奥美拉唑以及咪达唑仑作为大鼠CYP1A2,CYP2C6,CYP2D1,CYP2D2,CYP2E1和CYP3A2的探针底物,采用LC-MS/MS测定大鼠体内6种混合探针的血药浓度,计算药动学参数。结果:造模后甲苯磺丁脲在大鼠体内浓度显著升高、代谢减慢;咪达唑仑在大鼠体内浓度显著降低、代谢加快。给予抗抑郁文拉法辛后,茶碱、氯唑沙宗和咪达唑仑在大鼠体内浓度显著升高、代谢减慢。结论:利血平诱导的急性抑郁模型状态对大鼠CYP2D1和CYP2D2有中强抑制作用,对CYP3A2有中强诱导作用;给予文拉法辛后对模型大鼠CYP1A2,CYP2C6,CYP2E1,CYP3A2为中强抑制作用。     

Alpha-lipoic acid differently affects the reserpine-induced oxidative stress in the striatum and prefrontal cortex of rat brain

Antioxidative properties of alpha-lipoic acid (LA) are widely investigated in different in vivo and in vitro models. The aim of this study was to examine whether LA attenuates oxidative stress induced in rats by reserpine, a model substance frequently used to produce Parkinsonism in animals. Male Wistar rats were treated with reserpine (5 mg/kg) and LA (50 mg/kg) separately or in combination. The levels of reduced glutathione (GSH), glutathione disulfide (GSSG), nitric oxide (NO) and S-nitrosothiols as well as activities of glutathione peroxidase (GPx), glutathione-S-transferase (GST) and L-gamma-glutamyl transpeptidase (gamma-GT) were determined in the striatum and prefrontal cortex homogenates. In the striatum and prefrontal cortex a single dose of reserpine significantly enhanced levels of GSSG and NO but not that of S-nitrosothiols when compared with control. In the striatum, LA administered jointly with reserpine markedly increased the concentration of GSH and decreased GSSG level. In the prefrontal cortex, such treatment produced only an increasing tendency in GSH level but caused no changes in GSSG content. In both structures LA injected jointly with reserpine markedly decreased NO concentrations but did not cause significant changes in S-nitrosothiol levels when compared with control. Enzymatic activities of GPx and GST were intensified by LA in the striatum. In the prefrontal cortex, GPx activity was not altered, while that of GST was decreased. Gamma-GT activity was attenuated by reserpine in the striatum while LA reversed this effect. Such changes were not observed in the prefrontal cortex. The mode of LA action in the striatum during the reserpine-evoked oxidative stress strongly suggests that this compound may be of therapeutic value in the treatment of Parkinson's disease.     

中药制剂及保健品中添加的10种抗高血压药物监测

目的建立抗高血压药物盐酸可乐定、氢氯噻嗪、酒石酸美托洛尔、盐酸哌唑嗪、盐酸普萘洛尔、苯磺酸氨氯地平、利血平、硝苯地平、尼群地平、尼莫地平10种化合物的HPLC快速检测方法。方法采用GRACE Prevail C18色谱柱;梯度洗脱方式;利用相对容量因子和紫外光谱相似度双指标进行定性;相对容量因子法进行定量分析。结果建立了同时测定10种抗高血压药物的HPLC方法;采用双指标进行定性,增加了HPLC定性的准确性;相对校正因子的含量测定法,有效减少对照品的使用,加快HPLC的分析速度。结论本文建立了双指标定性、相对校正因子测定含量的HPLC方法,可以同时测定10种抗高血压药物,适用于中药制剂及保健品非法添加的快速监测。     

复方利血平片治疗原发性高血压的有效性和安全性系统评价

目的:评价复方利血平片治疗原发性高血压的疗效和安全性。方法:计算机检索Cochrane Library、PubMed、Embase、中国生物医学文献数据库(CBM)、中国期刊全文数据库(CNKI)、维普中文科技期刊全文数据库(VIP),制定严格的纳入和排除标准,纳入复方利血平片对比常规降压药治疗原发性高血压的随机对照试验,对纳入的随机对照试验进行方法学质量评价和Meta分析。由2名研究员对原始研究独立进行质量评价和资料提取,采用RevMan5.0软件进行Meta分析,根据各原始研究间异质性大小选择随机/固定效应模型,并进行敏感性分析和亚组分析。结果:共纳入11个随机对照试验,其中4篇为中等质量,其余7篇均为低质量。Meta分析结果显示,复方利血平片组与常规降压药组间降压效果的总有效率差异有统计学意义[RR=0.80,95%CI(0.74,0.85),P<0.00001];2组不良反应均较少见且轻微,未观察到严重不良反应事件。结论:根据目前研究证据,复方利血平片的降压有效率不及其他常规降压药,但2组降压药均安全、有效。由于观察例数和时间有限,上述结论仍需更多设计严谨、大样本、多中心的随机对照试验进行证实和补充。     

夏枯草香附水煎剂对行为绝望抑郁模型小鼠抗抑郁作用研究

目的：观察夏枯草香附水煎剂（SP-CR-W）的抗抑郁作用。方法：清洁级ICR小鼠50只,随机分空白对照组、盐酸氯米帕明组、夏枯草香附水煎剂高、中、低剂量（1．288、0．644、0．322g／kg）组,每组10只,分别予相应药物灌胃,10天。通过小鼠自主活动、小鼠悬尾实验（TST）、小鼠强迫游泳实验（FST）和利血平拮抗实验,评价夏枯草香附水煎剂的抗抑郁效果。结果：夏枯草香附水煎剂高、中剂量（1．288、0．644g／kg）均能显著缩短小鼠在TST及FST的不动时间（P〈0．05或P〈0．01）,对小鼠自主活动均无显著影响（P〉0．05）。夏枯草香附水煎剂各剂量组均能拮抗利血平注射后1h所致的小鼠降温作用,减少小鼠眼睑下垂数及呆在圈内的动物数。结论：夏枯草香附水煎剂可以改善小鼠抑郁行为,具有抗抑郁作用,且无中枢兴奋性作用。