HCMV感染对单核细胞HLA－DR表达的影响

本文采用细胞ＥＬＩＳＡ法，研究发现人巨细胞病毒（ＨＣＭＶ）感染对单核细胞ＨＬＡ－ＤＲ的影响。结果表明ＨＣＭＶ感染后１ｄ，单核细胞ＨＬＡ－ＤＲ表达显著增高（Ｐ＜０．０１），以后逐渐降低，ｄ５降至对照水平；ＩＦＮγ（５００Ｕ／ｍｌ）．ＴＮＦ（２５０Ｕ／ｍｌ）、ＩＬ－６（５００／ｍｌ）、ＩＬ－１（５００／ｍｌ）均能不同程度地刺激单核细胞ＨＬＡ－ＤＲ表达；ＨＣＭＶ感染后，细胞因子刺激ＨＬＡ－ＤＲ表达的水平在感染后ｄ５，较对照组均显著降低（Ｐ＜０．０１）；ＩＬ－１＋ＩＦＮ－γ及ＴＮＦ＋ＩＦＮ－γ在刺激单核细胞ＨＬＡ－ＤＲ表达时有协同作用；ＨＣＭＶ感染后，ＩＦＮ－γ＋ＩＬ－１及ＴＮＦ＋ＩＦＮ协同刺激单核细胞ＨＬＡ－ＤＲ表达水平较对照组显著降低（Ｐ＜０．０１）。结果提示：在ＨＣＭＶ感染引起免疫抑制过程中，其引起单核细胞ＨＬＡ－ＤＲ表达降低是一重要机制。     

HCMV感染对单核细胞HLA－DR表达的影响

本文采用细胞ＥＬＩＳＡ法，研究发现人巨细胞病毒（ＨＣＭＶ）感染对单核细胞ＨＬＡ－ＤＲ的影响。结果表明ＨＣＭＶ感染后１ｄ，单核细胞ＨＬＡ－ＤＲ表达显著增高（Ｐ＜０．０１），以后逐渐降低，ｄ５降至对照水平；ＩＦＮγ（５００Ｕ／ｍｌ）．ＴＮＦ（２５０Ｕ／ｍｌ）、ＩＬ－６（５００／ｍｌ）、ＩＬ－１（５００／ｍｌ）均能不同程度地刺激单核细胞ＨＬＡ－ＤＲ表达；ＨＣＭＶ感染后，细胞因子刺激ＨＬＡ－ＤＲ表达的水平在感染后ｄ５，较对照组均显著降低（Ｐ＜０．０１）；ＩＬ－１＋ＩＦＮ－γ及ＴＮＦ＋ＩＦＮ－γ在刺激单核细胞ＨＬＡ－ＤＲ表达时有协同作用；ＨＣＭＶ感染后，ＩＦＮ－γ＋ＩＬ－１及ＴＮＦ＋ＩＦＮ协同刺激单核细胞ＨＬＡ－ＤＲ表达水平较对照组显著降低（Ｐ＜０．０１）。结果提示：在ＨＣＭＶ感染引起免疫抑制过程中，其引起单核细胞ＨＬＡ－ＤＲ表达降低是一重要机制。     

单胺类递质在光化学诱导树鼩血栓性脑缺血中心区及半暗区形成中的作用

目的和方法：光化学诱导树鼠句血栓性脑缺血,用荧光分光光度法检测实验后４ 、２４ 及７２ ｈ 中心区及半暗区单胺类递质的变化,并用密度梯度法测定以上各区脑水份含量,以探讨单胺类递质代谢紊乱在缺血性脑损伤中的作用。结果：光化学反应后中心区与半暗区的多巴胺（ＤＡ） 、去甲肾上腺素（ＮＥ） 和５ － 羟色胺（５ － ＨＴ） 含量分别在４ 、２４ 及７２ ｈ 降至最低点（ 与假手术组相比Ｐ 均＜ ０－０１） ,然而５ － ＨＴ 的代谢产物—５ － 羟吲哚乙酸（５ － ＨＩＡＡ） 逐渐升高。中心区及半暗区脑水含量于实验后２４ ｈ 均达峰值（ Ｐ 均＜ ０－０１） 。结论：单胺类递质在光化学诱导树鼠句血栓性脑缺血,尤其是半暗区形成中具重要作用;其病理生理改变,既是血栓性脑缺血的结果,又是继发性脑损伤、脑水肿以及迟发性神经元坏死（ ＤＮＤ） 的原因     

犬脑干缺血后脑干听觉诱发电位的研究

建立犬脑干局灶性缺血模型，观察脑干局灶性缺血后脑干听觉诱发电位（ＢＡＥＰ）的变化。结果发现犬脑干缺血０．５、１、１．５、３、６和１２ｈ缺血组（ＩＳ）ＢＡＥＰ的Ⅰ、Ⅲ、Ｖ各波潜伏期（ＰＬ）及Ⅰ－Ⅲ、Ⅲ－Ｖ、Ⅰ－Ｖ波的峰间期（ＩＰＬ）与假手术组（ＳＨ）相比较均非常明显地延长（Ｐ＜０．０１），以１～１．５ｈ延长最显著（ｒ＜０．０１），３ｈ后各值逐渐缩短。提示ＢＡＥＰ可反映犬脑干缺血后的脑干损害，可客观地评价脑干功能。     

20—羟基蜕皮酮对银盾革蜱若虫蜕化期和存活作用的研究

在银盾革蜱若虫发育的不同时期：饱血后２ｄ（２－ｐＥ组）、６ｄ（６－ＰＥ组）和１２ｄ（１２－ＰＥ组）局部施用２０－羟基蜕皮酮，剂量分别为１、５、１０、２０和４０μｇ。结果表明处理时间（Ｔ）和施用剂量（Ｄ）对若虫蜕化期和存活有显著影响，双因素方差分析，Ｔ：ｄｆ＝２，Ｆ＝７３．７９，Ｐ＝０．０００；Ｄ：ｄｆ＝６，Ｆ＝３０．９７，Ｐ＝０．０００。单因素方差分析，剂量大于１０μｇ缩短了若虫蜕化期（差异极显著），１μｇ、５μｇ也有此效应（差异显著）。６－ＰＥ组效果最明显，与２－ＰＥ组、１２－ＰＥ组差异极显著。２０－羟基蜕皮酮对若虫有致死作用，蜕皮前死亡和蜕皮后死亡与施用剂量和时间有关，剂量大于１０μｇ时，所有实验组死亡率均为１００％。Ｐ＜０．０１表４施用剂量（２０－Ｅ）对若虫蜕化期的影响（Ｏｎｅ－ｗａｙＡＮＯＶＡ）Ｔａｂ．３Ｅｆｆｅｃｔｓｏｆｄｏｓａｇｅ（２０－Ｅ）ｏｎｎｙｍｐｈａｌｍｏｕｌｔｉｎｇｐｅｒｉｏｄ（Ｏｎｅ－ｗａｙＡＮＯＶＡ）：Ｐ＜０．０１：＊：Ｐ＜０．０５对照Ⅰ─未处理；对照Ⅱ─乙醇处理ＣｏｎｔｒｏｌⅠ─Ｕｎｔｒｅａｔｅｄ；Ｃｏｔｒｏｌ　Ⅱ─Ｅｔｈａｎｏｌ图１２－ＰＥ组若虫在不同剂量处理下的死亡率Ｆｉｇ．     

流行性出血热肾组织中增殖细胞核抗原,波形丝蛋？…

目的 研究流行悸出血热（ＥＨＦ）肾组织中增殖细胞核抗原（ＰＣＮＡ）入波形丝蛋白（Ｖｉｍｅｎｔｉｎ）的表达及意义。方法 应用多重ＰＡＰ免疫组化方法，对１７例ＥＨＦ尸检肾组织中客ｖｉｍｅｎｔｉｎ的表达进行观察。结果 ＥＨＦ尸有组织ＰＣＮＡ的阳乞率为６４．７１％，集合管的增殖指数显著大于远曲小管（Ｐ〈０．０１），低血压休克期患者远曲小管和集合管上皮细胞ｖｉｍｅｎｔｉｎ呈强阳性表达，相同部位ＰＣＮＡ也呈阳     

慢性风湿性心脏病患者的内皮素,内洋地黄素,心钠素的变化？…

用放射免疫法测定了４２例风湿性心脏病患者血内洋地黄素（ＥＤＦ）、内皮素（ＥＴ）与心钠素（ＡＮＰ）水平。结果显示，心脏功能越差，ＥＴ、ＡＮＦ越明显增高（Ｐ〈０．００１及Ｐ〈０．０１），且ＥＤＦ下降显著（Ｐ〈０．００１）。有培垛普利治疗后，ＥＴ、ＡＮＦ下降（Ｐ〈０．０５及０．００５）和ＥＤＦ增加（Ｐ〈０．０５）。提示测定ＥＤＦ、ＥＴ、ＡＮＰ有助于估计病情、判断疗效及预后     

高频喷射通气治疗PE—SWD兔血气和Na^＋—K^＋—ATPase图？…

为了探讨高频喷射通气（ＨＦＪＶ）治疗海水淹溺肺水肿（ＰＥ－ＳＷＤ）的作用机理,采用全自动血气酸碱分析仪和计算机图像分析系统对海水淹溺肺水肿组（ＰＥ－ＳＷＤ－Ｇ）、高频喷射通气组（ＨＦＪＶ－Ｇ）和正常对照组（ＯＮＴＲＯＬ ＧＲＯＰＵ,ｃｇ）兔ＰａＯ２、ＰａＣＯ２血氧饱和度（ＳａＯ２和兔肺内Ｎａ＾＋－Ｋ＾＋－ＡＴＰａｓｅ进行自动检测和定量分析。结果表明,ＰＥ－ＳＷＤ经ＨＦＪＶ治疗１００ｍｉｎ,ＨＦＪＶ     

SRBC膜提取物对猪PBMNC第二信使的影响

胰酶水解绵羊红细胞（ＳＲＢＣ）释放膜表面活性蛋白组分Ⅲ（ＴＲＦ－Ⅲ），单独作用可使猪外周血单个核细胞（ＰＢＭＮＣ）胞内ｃＡＭＰ水平升高，以１００μｇ／ｍｌ浓度刺激达最高峰，由对照组０．９４±０．１４ｐｍｏｌ／Ｌ升高到２．７５±０．２５ｐｍｏｌ／Ｌ（Ｐ＜０．０１）。如果ＰＢＭＮＣ事先与腺苷酸环化酶（ＡＣａｓｅ）抑制剂ＬｉC１孵育后再以ＴＲＦ－Ⅲ或ＰＡＨ刺激。ｃＡＭＰ增高受到抑制（Ｐ＜０．０１）；而ＥＤＴＡ－２Ｎａ（一种磷酸二酯酶ＰＤＥ抑制剂）对此ｃＡＭＰ升高无影响。结果提示，此ｃＡＭＰ升高主要是通过活化ＡＣａｓｅ水解ＡＴＰ生成ｃＡＭＰ，而不像是抑制ＰＤＥ减少ｃＡＭＰ降解引起的。ＴＲＦ－Ⅲ诱导猪ＰＢＭＮＣ胞内Ｃａ~(２＋)浓度升高，以１００μｇ／ｍｌ刺激２分钟升高最多，由对照组的２４２±７ｎｍｏｌ／Ｌ升高到３２３±１５ｎｍｏｌ／Ｌ（Ｐ＜０．０１）。以ＥＧ－ＴＡ除去胞外Ｃａ~(２＋)再以ＴＲＦ－Ⅲ或ＰＡＨ刺激，仅观察到小范围［Ｃａ~(２＋)］ｉ升高。看来这一过程包括了刺激胞内Ｃａ~(２＋)释放和胞外Ｃａ~(２＋)内流两种方式。以上结果证明，ＴＲＦ－Ⅲ对淋巴细胞功能影响与细胞内第二信使有关。     

淋巴细胞培养上清诱导低密度嗜酸细胞作用

分离豚鼠外周血淋巴细胞加入ＣｏｎＡ在体外培养后，收集上清液。１０－５ｍｏｌ／Ｌ的组胺不能诱导正常密度嗜酸细胞（ＮＥｏ）转变为低密度嗜酸细胞（ＨＥｏ），但Ｅｏｓ经淋巴细胞培养上清预处理后，组胺能明显地刺激ＮＥｏ转变为ＨＥｏ（Ｐ＜０．０５），１０－６ｍｏｌ／ＬＰＡＦ能诱导１５．９％的ＮＥｏ转变为ＨＥｏ，而经淋巴细胞培养上清预处理能显著增强ＰＡＦ的作用。淋巴细胞培养上清与Ｅｏｓ悬液１：１比例温育３０ｍｉｎ，对Ｅｏｓ密度无显著影响，但温育４８ｈ能显著地诱导ＮＥｏ转变为ＨＥｏ（Ｐ＜０．０１）。同样，淋巴细胞培养上清与Ｅｏｓ作用３０ｍｉｎ，不能诱导Ｅｏｓ脱颗粒，作用４８ｈ能诱导Ｅｏｓ释放约２８％的Ｅｏｓ过氧化物酶（ＥＰｏ）。以上表明淋巴细胞产物能致敏Ｅｏｓ，增强炎性介质刺激ＨＥｏ产生的能力。淋巴细胞产物诱导ＨＥｏ产生的作用较ＰＡＦ等缓慢，这种作用可能是刺激Ｅｏｓ脱颗粒的结果。     

Monoamines alter in vitro migration of chicken leukocytes

The effect of the biogenic amines serotonin (5-HT), dopamine (DA), and norepinephrine (NE) on peripheral blood leukocyte (PBL) migration was studied in two populations derived from line UNH 105 New Hampshire chickens. Maximum migration from capillary tube migration chambers was achieved in 1 hr. An age effect in both populations was indicated by significantly larger migration areas found in leukocytes from 7-week-old chickens compared to those of 4-week-old chicks. Thirty min after intravenous monoamine injection, line UNH 105 PBL migration was unaffected by exogenous monoamines. In the second population, B24/B24 chicks, NE enhanced migration at 4 weeks of age but DA suppressed migration at 7 weeks of age. In vitro exposure of PBL to the biogenic amines also affected leukocyte migration. Migration was augmented by 100 ng 5-HT but suppressed by 1 microgram 5-HT in UNH 105 chicks. Furthermore, DA suppressed PBL migration and NE enhanced migration in the same population. PBL from B24/B24 chicks were not affected by in vitro exposure to 5-HT, however, DA enhanced migration whereas NE suppressed migration. Specific antagonists for 5-HT, DA, and NE blocked the effects of each monoamine suggesting that receptors are present on chicken leukocytes. These receptors mediate action of the monoamines on leukocyte migration activity.     

Alteration in hypothalamic monoamine metabolism of freely moving diabetic rat.

Changes in hypothalamic monoamine metabolism were investigated in freely moving streptozotocin (STZ)-induced diabetic rats by using in vivo microdialysis technique. Six weeks later, the animals were implanted with microdialysis probe (molecular weight cut-off index: 12,000-14,000) into the ventromedial portion of the hypothalamus (VMH). The dialysate was collected and loaded onto HPLC to be assayed for norepinephrine (NE), dopamine (DA), serotonin (5-HT) and their metabolites (MHPG, DOPAC and 5-HIAA). The concentration of NE was decreased in the dialysate from the VMH of diabetic rats, whereas there was no significant change in MHPG level. The concentrations of 5-HT and 5-HIAA were reduced in diabetic rats. The DA concentration was obviously increased accompanied by the reduction of DOPAC level. The observed changes in hypothalamic monoamine metabolism, especially the reduced NE release, may play an important role in the induction of hyperphagia in freely moving STZ-induced diabetic rats.     

Monoaminc and metabolite levels in the cerebrospinal fluid of hibernating and euthermic marmots

SUMMARY  Cerebrospinal fluid from yellow-bellied marmots, Marmota flaviventris , was analysed for monoamine and monoamine metabolite content during euthermia and deep hibernation. Dopamine (DA) levels were decreased, while DA metabolite levels, dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), were dramatically increased in hibernating marmots. Serotonin (5-HT) and 5-hydroxyindoleacetic acid (5HIAA) levels were also greatly enhanced during hibernation while norepinephrine (NE) levels were only moderately increased. These findings demonstrate that cerebrospinal monoamine levels are dynamically altered during hibernation, such that DA versus 5-HT and NE levels undergo opposite changes. Therefore, these data indicate that DA, 5-HT and NE neuronal systems are differentially altered during hibernation in mammals.     

足月胎儿脐带动,静脉血中单胺类神经递质的含量

测定了足月正常娩出的胎儿脐带动.静脉血和健康临产孕妇肘静脉血中胺类神经递质的含量。结果表明.胎儿脐动、静脉血去甲肾上腺素(NE)和多巴胺(DA)都非常显著地高于孕妇静脉血中的含量(P<0.001);胎儿脐动、静黔血中5-羟吲哚乙酸(5-HIAA)显著高于孕妇血中的含量(P<0.05),但5-羟色胺(5-HT)和色氨酸(Trp)无明显变化:胎儿性别不影响单胺类递质的含量。     

Isolation rearing of rats alters release of 5-hydroxytryptamine and dopamine in the frontal cortex: an in vivo electrochemical study

Summary The effects of rearing hooded Lister rats either in groups of seven or singly on 5-hydroxytryptamine (5-HT) and dopamine (DA) release in the frontal cortex were investigated using in vivo voltammetry together with Nafion coated carbon fibre micro-electrodes. The selective detection of basal extracellular levels of 5-HT with this technique (Peak B) was confirmed with parallel experiments using intracranial microdialysis to measure 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) levels in vivo. The DA voltammetric signal (Peak A) was observed in vivo only following pharmacological or electrical stimulation of DA release. Enhanced efflux of cortical DA and 5-HT in response to local application of KCl and that of 5-HT following parentelar fenfluramine were selectively detected by the association: differential pulse voltammetry (DPV) — Nafion coated microbiosensors, supporting the capability of this electrochemical method to selectively monitor release of these amine neurotransmitters in vivo and in situ. The locomotor behaviour data indicated that isolation rearing resulted in augmented locomotor activity in a novel environment. In addition, the in vivo voltammetric results showed that following KC1 or fenfluramine treatment cortical 5-HT release is prolonged while that of DA is increased in rats reared in isolation when compared with socially reared rats. This imbalance between extracellular levels of DA and 5-HT recorded in the frontal cortex of rats exposed to isolated housing conditions may contribute to the behavioural differences reported between isolation and group reared rats.Abbreviations 5-HT 5-hydroxytryptamine - DA dopamine - 5-HIAA 5-hydroxyindoleacetic acid - DPV differential pulse voltammetry - CFE carbon fibre micro-electrode - DOPAC dihydroxy phenilacetic acid - FC frontal cortex - MAO-I monoamine oxidase inhibitor     

启神胶囊对全脑反复缺血再灌注大鼠脑内单胺类神经递质含量的影响

为了探讨启神胶囊对全脑反复缺血再灌注大鼠脑内单胺类神经递质的影响 ,Wister大鼠 ,采用 4-血管反复缺血再灌注造模 ,分正常对照组、模型组、模型喂药组 ,30天后取脑 ,用HPLC—ECD法测定 ,结果表明 ,模型大鼠海马组织中NE、MHPG、5—HT含量下降 ,与正常对照组差异显著 (p <0 .0 5 ) ;中药组大鼠海马组织中NE、MHPG、5—HT、HVA比模型鼠显著上升 (p <0 .0 5 )。模型大鼠大脑皮层中NE、MHPG、DA、HVA含量明显低于对照组 ,中药组NE、HVA含量均比模型组显著提高 (p <0 .0 5 ) ;MHPG、DA虽也有提高 ,但无统计学差异 ;5—HT含量 ,模型组高于对照组 (p <0 0 5 ) ,中药组低于模型组 (p <0 .0 5 )。启神胶囊能影响全脑缺血再灌注大鼠单胺类神经递质的代谢     

自发性高血压鼠脑内单胺类神经递质的变化

本实验用HPLC-ECD方法测定SHR和WKY大鼠的中枢单胺神经递质。在被测的六个脑区中(额叶皮质、尾状核、下丘脑前部、下丘脑后部、海马和延髓)发现NE和5-HT呈普遗下降趋势;DA在6月龄SHR尾状核升高明显;SHR的下丘脑和尾状核从3月龄到6月龄呈现一个递质的增减变化过程。实验提示:单胺神经递质在原发性高血压的发生和维持机制中起重要作用,下丘脑和尾状核是二个重要的递质血压相关区,尤其是尾状核的DA递质。     

Monoamine transmitter activity in lateral hypothalamus during its perfusion with insulin or 2-DG in sated and fasted rat

A unique profile of neurochemical events is proposed to occur in the diencephalon which is contingent upon the nutrient status of the animal. In this first of a series of investigations, we selected the lateral hypothalamus (LH) in order to determine its specific resting profile of monoaminergic neurotransmitters and their principal metabolites. The neuronal pattern of activity was studied during sated and fasted conditions as well as during a local glucoprivic challenge to the LH. After permanent guide cannulae for push-pull perfusion were implanted in female Sprague-Dawley rats, the LH was perfused repeatedly with an artificial CSF, at a rate of 20 microliters/min, in order to collect a series of 5.0 min samples. Aliquots of each perfusate were assayed directly using a high performance liquid chromatography system with electrochemical detection (HPLC-EC) for pg/microliter concentrations of norepinephrine (NE), dopamine (DA) and serotonin (5-HT). In comparison to the basal levels of amines during the sated condition, when the rat was food-deprived for 20-22 hr, the release of NE, DA, and 5-HT was significantly lower than that observed under the sated condition. Further, the turnover of NE in the LH was concurrently attenuated as reflected by the lower levels of MHPG in the perfusate, thus demonstrating the modification in catecholamine activity produced in the LH by the condition of hunger. When either 10 micrograms/microliters 2-deoxy-D-glucose (2-DG) or 4.0 mU/microliter insulin was incorporated into the CSF perfused in the LH, the efflux of DA was significantly enhanced independent of the state of satiation. In addition, the proportion of both NE and DA to 5-HT was likewise increased by either of these centrally acting substances, while the turnover of 5-HT was enhanced and NE and DA turnovers were reduced. Perfusion of 2-DG in the LH of the fasted rat caused a significant reduction in catecholamine turnover in terms of MHPG/NE, VMA/NE, DOPAC/DA and HVA/DA ratios. Moreover, 2-DG increased NE/5-HT while lowering the NE/DA ratio, and enhanced simultaneously the 5-HTOL/5-HT ratio. In the sated rat, 2-DG attenuated the release of 5-HT from the animal's LH, whereas insulin caused a shift in the proportions of NE/5-HT and DA/5-HT. Further, the peptide served to reduced the efflux of 5-HT, enhanced the turnover of 5-HT while diminishing DA turnover, and shifted the metabolism of NE from MHPG to VMA.(ABSTRACT TRUNCATED AT 400 WORDS)     

人参二醇皂甙对失血性休克犬单胺类递质和单胺氧化酶的影响

42只杂种犬按体重随机分为失血性休克组(HS)、人参二醇皂甙预治疗组(HSG)、地塞米松预治疗组(HSD)。实验过程中通过调整血容量维持平均动脉压至5.3kpa(40mmHg),定期采血测血消NE、DA、5-HT、5-HIAA及MAO的含量。结果表明:人参二醇皂甙不仅能阴止休克时NE、DA含量的增加,还能增加麻醉后NE的含量。而地塞米松只能阻止休克时NE含量的增加。人参二醇皂甙对5-HT的影响与地塞米松相同,失血3小时前5-HT含量逐渐增高,而于第4、5小时下降,提示二者均可抑制休克晚期血小板对5-HT的释放。单胺氧化酶的含量变化各组无显著差异。     

Effects of cocaine on monoamine uptake as measured ex vivo

The increase in extracellular dopamine (DA) following cocaine administration plays a major role in cocaine abuse. In vitro, cocaine binds to DA transporters (DAT) and blocks DA uptake. Moreover, cocaine can increase extracellular DA concentration as measured by in vivo neurochemical methods. The present study examined the effects of cocaine and other drugs on DA, NE and 5-HT uptake using an ex vivo assay. Rats were injected i.v. with saline or drug and sacrificed at various time points after injections. Brains were dissected for regional monoamine uptake studies ex vivo. In most brain regions, cocaine given in vivo blocked monoamine uptake as expected. [3H]DA uptake in nucleus accumbens was inhibited with an ED50=22.3 micromol/kg. Cocaine fully inhibited [3H]NE uptake (ED50=4.58 micromol/kg) in the occipital cortex and partially inhibited [3H]5-HT uptake (33% at 30 micromol/kg) in the midbrain. However, under the same conditions [3H]DA uptake in the striatum was not inhibited after injections of cocaine up to 56 micromol/kg. Although the mechanism for this discrepancy is unclear, DA binding and uptake sites may be distinct and/or there may be regional differences in DA transporters.