2′－甲基甲苯氢啶对小鼠不同脑区单胺类神经递质含量的影响

为了评价１－甲基－４－苯基－１，２，３，６四氢吡啶（２′－甲基甲苯氢啶或２′－ＣＨ３－ＭＰＴＰ）的作用，提供新的帕金森病模型的工具药，通过高效液相色谱电化学检测法对２′－甲基甲苯氢啶在小鼠不同脑区去甲肾上腺素、多巴胺（ＤＡ）、５－羟色胺（５－ＨＴ）、多巴酸和高香草酸的作用进行了研究测定。结果表明：２′－甲基甲苯氢啶对纹状体多巴胺能神经有选择性破坏作用。１０ｍｇ／ｋｇ组给药１５天，１５ｍｇ／ｋｇ组给药５天，２０ｍｇ／ｋｇ组给药１天，均能使小鼠纹状体多巴胺及其代谢产物的含量明显降低，第２天尤为显著。随着时间的延长，有一定程度的恢复，但至２０天仍处于较低水平；而对５－ＨＴ及其代谢产物无明显影响；能明显降低额叶皮层内的去甲肾上腺素含量；低剂量给药，对ＤＡ的抑制强度仍明显强于甲苯氢啶（ＭＰＴＰ），差异有显著意义（Ｐ均＜０．００１）。结果显示：２′－甲基甲苯氢啶对多巴胺神经元的抑制作用特异且较为持久，作用明显强于ＭＰＴＰ，可作为帕金森病动物模型的工具药应用     

6—羟多巴胺损毁的大鼠纹状体内多巴胺排空与左旋千金藤啶碱引起的？…

用高效液相－电化学检测器和旋转计数的方法检测６－羟多巴胺（６－ｈｙｄｒｏｘｙｄｏｐａｍｉｎｅ，６－ＯＨＤＡ）损毁大鼠纹状体多巴胺（ｄｏｐａｍｉｎｅ，ＤＡ）排空与旋转的关系，Ｄ１／Ｄ２混合性激动剂阿扑吗啡（ａｐｏｍｏｒｐｈｉｎｅ，ＡＰＯ，０．２ｍｇ／ｋｇ，ｉｐ）可使３３只大鼠中的２０只出现旋转，其中１５只旋转强度〉５次／分钟，平均为１２．１±５．８次／分钟。Ｄ１选择性激动剂ＳＫＦ３８３９３，Ｄ２选择     

一氧化氮与帕金森病小鼠模型神经损害的研究

目的　研究一氧化氮（ＮＯ） 在帕金森病（ＰＤ）小鼠模型神经损害中的作用。方法　用比色分析、高效液相色谱电化学及免疫组化法检测１甲基４苯基四氢吡啶（ＭＰＴＰ）和７硝基吲唑（７ＮＩ）对Ｃ５７ＢＬ小鼠纹状体一氧化氮合酶（ＮＯＳ） 活性,多巴胺（ＤＡ）、二羟基苯乙酸（ＤＯＰＡＣ）、高香草酸（ＨＶＡ） 水平和酪氨酸羟化酶（ＴＨ） 免疫阳性神经纤维的影响。结果　注射ＭＰＴＰ后Ｃ５７ＢＬ小鼠纹状体ＮＯＳ活性增加,７ＮＩ能明显抑制ＭＰＴＰ引起的ＮＯＳ活性的升高（ 分别为０ ．９３ ±０．２４ 和０．５４ ±０．１６,ｎｍｏｌ·ｍｉｎ－１·ｇ－１ 组织,Ｐ＜０．０１） 。７ＮＩ能明显减轻ＭＰＴＰ引起的Ｃ５７ＢＬ小鼠纹状体ＤＡ（ 分别为０ ．８ ±０ ．２ 和６．８±０．５,μｇ／ｇ 组织,Ｐ＜０．０１） 、ＤＰＯＡＣ（ 分别为０．３ ±０．１ 和０ ．９ ±０ ．３ ,μｇ／ｇ 组织,Ｐ＜ ０ ．０１）、ＨＶＡ（分别为０．４±０．２ 和０．９ ±０ ．２,μｇ／ｇ 湿组织,Ｐ＜ ０．０１） 的降低及ＴＨ 阳性神经纤维损害。结论神经元来源的ＮＯ 参与了ＭＰＴＰ的毒性机制,神经元型ＮＯＳ抑制剂可能有益于ＰＤ的治疗。     

免疫应答期间脑内多巴胺代谢的变化

应用高效液相色谱－电化学检测法（ＨＰＬＣ－ＥＣＤ）测定大鼠用绵羊红细胞（ＳＲＢＣ）免疫后第２－７天期间，下丘脑，海马和脑干中多巴胺（ＤＡ）及代谢产物高香草酸（ＨＶＡ）的含量，结果表明，下丘脑中ＤＡ含量，在免疫后第３－４天明显升高，第５天明显降低，ＨＶＡ含量在免疫后第２－５天显著地增加，以第４天增加最多，海马中ＤＡ含量在免疫后第５－７天明显减少，而ＨＶＡ含量在此期间显著增加，均以第６天变化最大，脑干     

抑郁症患者脑脊液生长抑素及单胺代谢产物浓度与临床症状的关系

目的 探讨抑郁症患者脑脊液生长抑素（ＳＳ）和单胺代谢产物浓度与临床症状的关系,以及神经递质之间的相互作用。方法 应用放射免疫测定方法和高效液相色谱法,测定２３例抑郁症患者脑脊液ＳＳ和５－羟色胺（５－ＨＴ）代谢产物５－羟吲哚之酸（５－ＨＩＡＡ）、去甲肾上腺素（ＮＥ）代谢产物３－甲基－４－羟－苯乙二醇（ＮＨＰＧ）及多巴胺（ＤＡ）代谢产物高香草酸（ＨＶＡ）的浓度。临床症状评估采用汉密尔顿抑郁量表（ＨＡＭ     

硫酸镁对大鼠脑缺血再灌流损伤保护作用的研究

目的:探讨ＭｇＳＯ４对大鼠脑缺血再灌流损伤的保护作用。方法:线栓法将ＳＤ大鼠制成脑缺血再灌流模型,分组测定脑组织Ｎａ＋－Ｋ＋－ＡＴＰａｓｅ活性、ＭＤＡ、ＮＯ含量。结果:治疗１组(３００ｍｇ·ｋｇ－１)和治疗２组(６００ｍｇ·ｋｇ－１)与对照组比较,Ｎａ＋－Ｋ＋－ＡＴＰａｓｅ活性增加,ＭＤＡ、ＮＯ含量降低,且治疗２组比治疗１组作用更明显。结论:ＭｇＳＯ４对脑缺血再灌流损伤有保护作用,６００ｍｇ·ｋｇ－１较３００ｍｇ·ｋｇ－１更显著。     

高频刺激底丘脑核阻止帕金森病黑质多巴胺能神经元变性的 …

目的 评价电刺激底丘脑核（ＳＴＮ）对帕金森病黑质多巴胺能神经元变性的影响。方法 实验用大鼠随机分为四组：第１组 纹状体仅注射６－羟基多巴（６－０ＨＤＡ）;第２组 底丘脑核区插入电极进行刺激组;第３组 底丘脑核刺激后６－ＯＨＤＡ再注射纹状体组;第４组 假刺激 丘脑核后再注射６－ＯＨＤＡ入纹状体组。手术后６周,分别观察各组大鼠阿朴吗啡诱发旋转行为及黑质多巴胺能神经地改变情况。     

电针对慢性应激抑郁模型大鼠脑单胺类神经递质的影响

目的　探讨电针刺激百会、印堂穴对慢性应激抑郁模型大鼠脑内单胺类神经递质的影响及治疗抑郁症的机理。方法　将２４ 只ＳｐｒａｇｕｅＤａｗｌｅｙ 雄性大鼠随机分为对照组、抑郁模型组、抑郁模型加电针组和抑郁模型加阿米替林组,每组６ 只。用高效液相电化学法测定大鼠脑内单胺类神经递质及其代谢产物的含量,比较含量的比值。结果　抑郁模型组大鼠脑皮层５羟色胺（５ＨＴ）／５羟吲哚乙酸（５ＨＩＡＡ） 、纹状体多巴胺（ＤＡ）／３,４二羟基苯乙酸（ＤＯＰＡＣ） 分别为０－５０ ±０－１７,１０－３７ ±１－４０,低于对照组（ 分别为０－８８±０－２５ ,１２－３６ ±１－５０）,Ｐ＜ ０－０５ ;皮层去甲肾上腺素（ＮＥ）／５ＨＴ（２－８８ ±１－００） 高于对照组（１－７３±０－４０） ,Ｐ＜ ０－０５。电针刺激百会、印堂穴可使模型大鼠脑皮层５ＨＴ／５ＨＩＡＡ 与ＮＥ／５ＨＴ恢复正常（Ｐ＜０－０５） ,对纹状体ＤＡ／ＤＯＰＡＣ 的降低无影响（ Ｐ＞ ０－０５）。结论　提示电针刺激百会、印堂穴通过降低皮层５ＨＴ的代谢,提高５ＨＴ能神经的活性,并协调ＮＥ 与５ＨＴ之间的平衡来发挥抗抑郁作用。     

一氧化氮合酶抑制剂对戊四氮诱导大鼠点燃模型及该酶阳性神经元的影响

目的：探讨一氧化氮（ＮＯ）在癫癎 发病中的作用．方法：ｉｐ ４０ｍｇ·ｋｇ－１·ｄ－１戊四氮 ３０ｍｉｎ前注射 ２５ｍｇ·ｋｇ－１的 ＮＧ－硝基－左旋－精氨酸（Ｌ－ＮＮＡ）,连续 ２２ｄ,观察两组的行为改变及点燃串,同时对 ３组动物海马,大脑皮质一氧化氮合酶（ＮＯＳ）阳性神经元的变化输入图像扫描仪,对其胞体平均灰度值进行比较。结果：Ｌ－ＮＮＡ可明显抑制戊四氮点燃模型;戊四氮点燃大鼠模型海马,大脑皮质神经元的ＮＯＳ活性显著增高．结论：ＮＯ参与了戊四氮点燃模型的形成。     

高频刺激底丘脑核阻止帕金森病黑质多巴胺能神经元变性的实验研究

目的评价电刺激底丘脑核（ＳＴＮ）对帕金森病黑质多巴胺能神经元变性的影响。方法　实验用大鼠随机分为四组：第１组　纹状体仅注射６－羟基多巴（６－ＯＨＤＡ）;第２组　底丘脑核区插入电极进行刺激组;第３组　底丘脑核刺激后６－ＯＨＤＡ再注射纹状体组;第４组　假刺激底丘脑核后再注射６－ＯＨＤＡ入纹状体组。手术后６周,分别观察各组大鼠阿朴吗啡（ＡＰＯ）诱发旋转行为及黑质多巴胺能神经元改变情况。结果第１、４组出现明显的ＡＰＯ诱发对侧旋转行为,第２、３组出现同侧旋转;酪氨酸羟化酶（ＴＨ）免疫组织化学染色显示,黑质区ＴＨ免疫反应（ＴＨ－ＩＲ）神经元数目在２、３组双侧无明显不同,而１、４组注射侧ＴＨ－ＩＲ神经元数目显著降低（Ｐ＜０．０１）。结论我们的结果表明,ＳＴＮ电刺激可以保护黑质多巴胺能神经元免受６－ＯＨＤＡ的毒性损害,提示这种治疗方法可以阻止或延缓帕金森病的继续发展和恶化。     

Specificity and efficacy of noradrenaline, serotonin depletion in discrete brain areas of Swiss mice by neurotoxins

The aim of this work is to define neurotoxins doses to have efficient and specific depletion of noradrenaline (NA), serotonin (5-HT) neurotransmission in cortex, striatum, hippocampus and hypothalamus of Swiss mice after intraperitoneal administration of, respectively, N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride (DSP-4) and para-chlorophenylalanine methyl ester hydrochloride (PCPA). The neurotransmitters concentrations were determined by high performance liquid chromatography with amperometric detection. The minimal single dose necessary to produce a highly significant decrease of NA levels (p<0.01 in comparison with control group) in hypothalamus (-44%), hippocampus (-91%), striatum (-40%) and cortex (-68%) was 50mg/kg but DA and 5-HT levels were modified, respectively, in hypothalamus and striatum. Three doses of PCPA 300 mg/kg over 3 consecutive days involve a profound depletion of 5-HT transmission in all discrete brain areas but NA and DA levels were also significantly reduced. In conclusion, DSP-4 has a different efficacy in discrete brain areas with a noradrenergic specificity which is not absolute, PCPA has a similar efficacy in all brain areas but is unspecific of 5-HT transmission.     

Topographical distribution of amines and major amine metabolites in the rat striatum

The topographical distribution of the proposed amine transmitters dopamine (DA), serotonin (5-HT), noradrenaline (NA), adrenaline and histamine (HA) and of the metabolites of DA and 5-HT has been investigated in the neostriatum of the rat. DA and, less pronounced, its metabolites 3,4-dihydroxyphenylacetic acid, homovanillic acid and 3-methoxytyramine exhibited gradients with highest levels in dorso-rostral areas and the lowest content in the ventro-caudal part of the striatum. In contrast to this 5-HT, 5-hydroxyindole-acetic acid, and NA exhibited levels which increased from frontal and dorsal areas to the ventro-caudal part of the striatum. The rostral nucleus accumbens and the pallidum were low in DA and high in 5-HT and NA when compared with the dorsal striatum. The turnover rates of DA and 5-HT as judged by the metabolite/amine ratios followed a distribution which was opposite to the respective amine levels. Adrenaline was evenly low in the striatum and only slightly higher in the n. accumbens and pallidum. The levels of HA were considerably lower than those of the other amines. Although HA was also unevenly distributed within the striatum, no clear pattern was found. The topographical distribution of the amines suggests a preferential role of DA in the dorsal striatum and of 5-HT and NA in the ventral part of the striatum including the n. accumbens and the pallidum.     

Effects of nitric oxide synthesis inhibition on methamphetamine-induced dopaminergic and serotonergic neurotoxicity in the rat brain

Summary We examined effects of nitric oxide (NO·) synthesis inhibition on methamphetamine (MA)-induced dopaminergic and serotonergic neurotoxicity. The toxic dose of MA (5 mg/kg, sc, X4) significantly decreased contents of dopamine (DA), dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the striatum (ST), and significantly decreased contents of serotonin (5-HT) in the ST, nucleus accumbens (NA) and medial frontal contex (MFC). Coadministration with a NO· synthase inhibitor, N-nitro-L-arginine methyl ester (LNAME) (30 mg/kg, ip, X2), reduced the MA-induced decreases in contents of DA, DOPAC and HVA in the ST, but not reduced the MA-induced decreases in contents of 5-HT in the ST, NA and MFC. These findings suggest that the MA-induced dopaminergic, but not serotonergic neurotoxicity, may be related to the neural process such as NO· formation caused by the activation of postsynaptic DA receptor.     

Neurotoxic effects of (±)fenfluramine and phentermine,alone and in combination,on monoamine neurons in the mouse brain

Until recently, (±)fenfluramine (FEN) was widely prescribed as an appetite suppressant. In animals, FEN is a potent and selective brain serotonin neurotoxin. The present studies assessed the effects of phentermine (PHEN), an appetite suppressant frequently used clinically in combination with FEN, on FEN-induced serotonin neurotoxicity. Groups (n = 6/group) of mice were treated with FEN (10 mg/kg), PHEN (20 mg/kg or 40 mg/kg), FEN (10 mg/kg) plus PHEN (20 mg/kg or 40 mg/kg), or vehicle twice daily for four days. Food intake and body weight were measured during and after drug treatment. Brains were evaluated for regional brain serotonin and dopamine axonal markers two weeks after drug treatment. PHEN enhanced the anorectic and weight-reducing effects of FEN. PHEN also significantly enhanced FEN's long-term toxic effects on 5-HT axons. This effect was evident in some (hypothalamus, striatum) but not all (hippocampus, cortex) brain regions examined. PHEN alone produced no long-term effects on 5-HT axonal markers. However, whether given alone or in combination with FEN, PHEN produced significant, dose-related decreases in striatal DA axonal markers. These results, coupled with those from previous studies, suggest that PHEN has the potential to exacerbate FEN-induced serotonin neurotoxicity, if utilized in certain doses. Further, the present results indicate that PHEN possesses dopamine (DA) neurotoxic potential. The relevance of these data to humans previously treated with FEN/PHEN is discussed. Synapse 30:239–246, 1998. © 1998 Wiley-Liss, Inc.     

The N-methyl-D-aspartate antagonist MK-801 protects against serotonin depletions induced by methamphetamine, 3,4-methylenedioxymethamphetamine and p-chloroamphetamine.

The non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 blocks the ability of D-methamphetamine (MA) to deplete striatal dopamine (DA). We now report that MK-801 attenuates decreases in serotonin (5-HT) concentration induced by MA and two other amphetamine analogues, 3,4-methylenedioxymethamphetamine (MDMA) and p-chloroamphetamine (PCA). Rats were injected with saline (1.0 ml/kg) or MK-801 (0.5, 1.0 or 2.5 mg/kg) followed by either saline (1.0 mg/kg), MA (4, 2 or 1 injection(s); 10.0, 20.0 or 40.0 mg/kg), MDMA (20.0 or 40.0 mg/kg) or PCA (5.0 or 10.0 mg/kg). In some experiments, two injections of MK-801 or saline were used. Seventy-two hours after the last injection rats were sacrificed and concentrations of 5-HT, 5-hydroxyindoleacetic acid (5-HIAA) and DA were determined in hippocampus and striatum. MA caused a depletion of 5-HT to 33% of control in hippocampus and to 50% of control in striatum after the 4 x 10.0 mg/kg dose regimen. When MK-801 (2.5 mg/kg) was co-administered with MA, concentrations of 5-HT did not differ from control levels in either brain region. MDMA depleted 5-HT to approximately 58% of control in hippocampus and 66% of control in striatum at the 40 mg/kg dose.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of oral administration of chlordecone and mirex on brain biogenic amines in mice

Levels of norepinephrine (NE), dopamine (DA), serotonin (5-HT) and the 5-HT metabolite, 5-hydroxyindole acetic acid (5-HIAA) were determined in brains of mice after daily oral administration of 10, 25 or 50 mg/kg of chlordecone or mirex until mortality occurred. Significant decreases in whole brain and striatal DA levels were observed in chlordecone-treated mice exhibiting tremors. Mirex had no effect at the 3 doses tested. In mice treated with chlordecone or mirex, the 5-HT levels were elevated only in animals exhibiting severe tremors or diarrhea, respectively. NE levels were not altered by chlordecone or mirex. These results suggest that chlordecone-induced neurotoxicity may be due in part to a decrease in the inhibitory state of dopamine neurons.     

Selective changes in the contents of noradrenaline, dopamine and serotonin in rat brain areas during aging

This study examines the age-associated changes in noradrenaline (NA), dopamine (DA), 3,4-dihydroxyphenyl-acetic acid (DOPAC), serotonin (5-HT) and 5-hydroxy-3-indoleacetic acid (5-HIAA) in different brain areas of rats. DA and DOPAC concentrations in striatum increased at third month of age, remaining without significant variations until 12th month of age, and decreasing in 24-month-old rats. DA concentration dropped in hippocampus, amygdala and brainstem of 24-month-old-rats, whereas DOPAC levels decreased only in hippocampus. These changes suggest an age-dependent deficit of the dopaminergic system, presumably related to a reduced number/activity of DA nigrostriatal and mesolimbic neurons. An age-induced decline in NA content was found in the pons-medulla, the area containing NA neuronal bodies. Concentrations of 5-HT were reduced with aging in frontal cortex, showing a tendency to decrease in all brain areas examined. The increased 5-HIAA/5-HT ratio found in frontal cortex, amygdala and striatum suggests an age-related decreased synthesis and an accelerated 5-HT metabolism. The 5-HIAA content decreased in brainstem of the oldest rats. These findings point to a selective impairment of nigrostriatal and mesolimbic DA in aging rats, whereas reductions in NA were restricted to cell bodies region and 5-HT showed changes of different extent in areas of terminals and neuronal cell bodies.     

Methamphetamine neurotoxicity and striatal glutamate release: comparison to 3,4-methylenedioxymethamphetamine.

The effect of repeated administration of either methamphetamine (MA), 3,4-methylenedioxymethamphetamine (MDMA) or vehicle on the extracellular concentrations of glutamate (GLU), aspartate, taurine, dopamine (DA) and its metabolite, 3,4-dihydroxyphenylacetic acid (DOPAC), was studied in awake, freely moving rats using in vivo microdialysis. MA (7.5 mg/kg, i.p.) administered every 2 h for a total of 3 injections, increased the extracellular concentration of GLU in the anteromedial striatum. By contrast, neither vehicle nor MDMA (9.2 and 13.8 mg/kg) increased GLU efflux following repeated administration. Both MA and MDMA increased the extracellular concentration of DA in the striatum. However, the cumulative increase in DA was significantly greater in the MDMA treated animals as compared to the MA group. The concentrations of DA, serotonin (5-HT) and their metabolites were determined in the striatum 7 days following the repeated administration of MA, MDMA and vehicle. MA, but not MDMA or vehicle, decreased the concentration of DA in the striatum. Conversely, MDMA (13.8 mg/kg) decreased the concentration of 5-HT, whereas MA, MDMA (9.2 mg/kg) and vehicle had no effect on striatal 5-HT content. These data are suggestive that the long-term (7 day) DA neurotoxicity produced by the repeated administration of MA is mediated, in part, by a delayed increase in extracellular concentrations of GLU. In contrast, repeated administration of MDMA, at a dose which produced a long-term (7 day) depletion of striatal 5-HT content, had no effect on GLU efflux in the striatum.     

Effects of valproate on amino acid and monoamine concentrations in striatum of audiogenic seizure-prone balb/c mice

The effects of aalproate on CNS concentrations of γ-aminobutyric acid (GABA), glutamate (GLU), glutamine (GLN), dopamine (DA), serotonin (5-HT), and metabolites were examined in tissue extracts of caudate nucleus of genetic substrains of Balb/c mice susceptible (EP) or resistant (ER) to audiogenic seizures. Generalized tonic-clonic seizures observed in EP mice were inhibited by valproate, administered 1 h prior to testing, in a dose-response fashion. Concentrations of GABA, GLU, and GLN, which were lower in EP mice than in ER mice, were significantly increased by valproate at doses of 180 and 360 mg/kg. Concentrations of homovanillic acid (HVA) and hydroxyindoleacetic acid (5-HIAA), metabolites of DA and 5-HT were substantially increased by valproate at these doses. Thein situ activity of tyrosine hydroxylase (TH) was not significantly influenced by valproate, whereas a valproate-induced increase in tryptophan hydroxylase (TPH) activity was observed in both striatum and in midbrain tegmentum. The data are consistent with the interpretation that anticonvulsive doses of valproate influences the intraneuronal metabolism of monoamines, GABA, and glutamate concurrently. Valproate’s influence on the metabolism of both major inhibitory (GABA) and excitatory (GLU) amino acids in striatum could contribute to its anticonvulsive effects in genetically seizure-prone mice, as well as to the accumulation of DA and 5-HT metabolites.     

Effects of ketamine on dopamine metabolism during anesthesia in discrete brain regions in mice: comparison with the effects during the recovery and subanesthetic phases

The effects of ketamine on the levels of dopamine (DA), norepinephrine (NE), 5-hydroxytryptamine (5-HT, serotonin) and their metabolites were examined in discrete brain regions in mice. A high dose of ketamine (150 mg/kg, i.p.) did not change DA metabolism in the frontal cortex, nucleus accumbens, striatum and hippocampus, but did decrease it in the brainstem during anesthesia. In contrast, during recovery from the ketamine anesthesia, the high dose increased the level of homovanillic acid (HVA) in all brain regions. A low subanesthetic dose of ketamine (30 mg/kg, i.p.) increased the concentrations of both 3,4-dihydroxyphenylacetic acid (DOPAC) and HVA only in the nucleus accumbens. The DA level was not affected by any ketamine treatment. During ketamine anesthesia, the content of 3-methoxy-4-hydroxy-phenylglycol (MHPG) was decreased in the brainstem, whereas during recovery from anesthesia, the MHPG level was increased in the frontal cortex, nucleus accumbens and brainstem. The NE content was not altered in any region by ketamine treatment. The concentration of 5-hydroxyindoleacetic acid (5-HIAA) was reduced in the frontal cortex, striatum, hippocampus and brainstem during ketamine anesthesia. The 5-HT level was unaltered in all regions except the brainstem where it was reduced. In contrast, after anesthesia, the concentrations of both 5-HT and 5-HIAA were increased in the striatum. During the subanesthetic phase, however, the levels of NE, 5-HT and their metabolites were unchanged. These neurochemical results are consistent with the electrophysiological findings that a high dose of ketamine does not change the basal firing rates of nigrostriatal DA neurons during anesthesia, while low subanesthetic doses significantly increase those of ventral tegmental DA neurons.