共查询到20条相似文献，搜索用时 15 毫秒
1.
Neuroleptic-induced decrease in plasma homovanillic acid and antipsychotic activity in schizophrenic patients 总被引：3，自引：0，他引：3
D Pickar R Labarca M Linnoila A Roy D Hommer D Everett S M Paul 《Science (New York, N.Y.)》1984,225(4665):954-957
Plasma-free homovanillic acid, a major metabolite of dopamine, was measured in chronically ill schizophrenic patients both before and during treatment with the antipsychotic phenothiazine, fluphenazine. Neuroleptic treatment was associated with a significant time-dependent decrease in plasma homovanillic acid from pretreatment values, which were significantly elevated when compared with those of age- and sex-matched healthy control subjects. Further, both the absolute concentrations as well as the neuroleptic-induced reductions in plasma homovanillic acid determined over 5 weeks of neuroleptic treatment were statistically significantly correlated with ratings of psychosis and improvement in psychosis, respectively. These findings suggest that the delayed effects of neuroleptic agents on presynaptic dopamine activity may more closely parallel their therapeutic actions than do their immediate effects in blocking postsynaptic dopamine receptors and that a decrease in dopamine "turnover" may be responsible for their antipsychotic effects. 相似文献
2.
Chronic blockade of dopamine D2 receptors, a common mechanism of action for antipsychotic drugs, down-regulates D1 receptors in the prefrontal cortex and, as shown here, produces severe impairments in working memory. These deficits were reversed in monkeys by short-term coadministration of a D1 agonist, ABT 431, and this improvement was sustained for more than a year after cessation of D1 treatment. These findings indicate that pharmacological modulation of the D1 signaling pathway can produce long-lasting changes in functional circuits underlying working memory. Resetting this pathway by brief exposure to the agonist may provide a valuable strategy for therapeutic intervention in schizophrenia and other dopamine dysfunctional states. 相似文献
3.
Parkinson's disease (PD) is a complex disorder with many different causes, yet they may intersect in common pathways, raising the possibility that neuroprotective agents may have broad applicability in the treatment of PD. Current evidence suggests that mitochondrial complex I inhibition may be the central cause of sporadic PD and that derangements in complex I cause alpha-synuclein aggregation, which contributes to the demise of dopamine neurons. Accumulation and aggregation of alpha-synuclein may further contribute to the death of dopamine neurons through impairments in protein handling and detoxification. Dysfunction of parkin (a ubiquitin E3 ligase) and DJ-1 could contribute to these deficits. Strategies aimed at restoring complex I activity, reducing oxidative stress and alpha-synuclein aggregation, and enhancing protein degradation may hold particular promise as powerful neuroprotective agents in the treatment of PD. 相似文献
4.
1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine destroys dopamine neurons in explants of rat embryo mesencephalon 总被引：11，自引：0，他引：11
Explants of embryonic rat mesencephalon were grown in organotypic culture. Addition of 10 microM 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to the culture medium for 4 to 7 days resulted in loss of dopamine cell bodies and fiber outgrowths, as observed by fluorescence histochemistry. At the same time, the cultures showed decreased uptake of tritium-labeled dopamine. However, no signs of generalized toxicity were evident when the explant cultures were viewed by light and phase-contrast microscopy. These results show that MPTP exerts a relatively selective destructive action in dopamine neurons in vitro, similar to the action observed in humans and monkeys in vivo. Pargyline (10 microM), a monoamine oxidase inhibitor, protected the dopamine neurons in the explants. Organotypic cultures provide an experimental model for the study of the properties of MPTP in vitro. 相似文献
5.
Serum dopamine beta-hydroxylase activity, a useful biochemical index of peripheral sympathetic nervous activity, was measured in rats treated with Delta(9)-tetrahydrocannabinol or ethanol or both substances. After 7 days of treatment with either substance, serum dopamine beta-hydroxylase activity decreased significantly. Combined treatment with both agents enhanced the effects of each given alone. In rats subjected to immobilization stress, treatment with Delta(9)- tetrahydrocannabinol appeared to potentiate the stress-induced increase in serum enzyme activity. Treatment with ethanol, with or without Delta(9)-tetrahydrocannabinol, effectively blocked this increase in enzyme activity. These results show that both substances have significant effects on the sympathetic nervous system which are critically influenced by environmental setting. 相似文献
6.
D1 and D2 dopamine receptor-regulated gene expression of striatonigral and striatopallidal neurons 总被引：63，自引：0，他引：63
C R Gerfen T M Engber L C Mahan Z Susel T N Chase F J Monsma D R Sibley 《Science (New York, N.Y.)》1990,250(4986):1429-1432
The striatum, which is the major component of the basal ganglia in the brain, is regulated in part by dopaminergic input from the substantia nigra. Severe movement disorders result from the loss of striatal dopamine in patients with Parkinson's disease. Rats with lesions of the nigrostriatal dopamine pathway caused by 6-hydroxydopamine (6-OHDA) serve as a model for Parkinson's disease and show alterations in gene expression in the two major output systems of the striatum to the globus pallidus and substantia nigra. Striatopallidal neurons show a 6-OHDA-induced elevation in their specific expression of messenger RNAs (mRNAs) encoding the D2 dopamine receptor and enkephalin, which is reversed by subsequent continuous treatment with the D2 agonist quinpirole. Conversely, striatonigral neurons show a 6-OHDA-induced reduction in their specific expression of mRNAs encoding the D1 dopamine receptor and substance P, which is reversed by subsequent daily injections of the D1 agonist SKF-38393. This treatment also increases dynorphin mRNA in striatonigral neurons. Thus, the differential effects of dopamine on striatonigral and striatopallidal neurons are mediated by their specific expression of D1 and D2 dopamine receptor subtypes, respectively. 相似文献
7.
[目的]为控制和延缓采后果蔬抗坏血酸（ASA）含量的下降提供理论支持。[方法]以采后红提和青椒为试材,研究热激和储藏温度对其ASA含量及代谢相关酶活性变化的影响。[结果]15℃下青椒和红提的ASA含量下降比25℃下慢。经过10 min热激处理后,红提的ASA含量瞬间上升,随后迅速下降;青椒中ASA含量有部分损失。说明热激处理不能有效延缓红提ASA含量的下降,可以延缓青椒ASA含量的下降,提高青椒贮藏品质。不同温度下抗坏血酸过氧化物酶（APX）和抗坏血酸氧化酶（AAO）活性均呈下降趋势。经过10 min热激处理后,红提的APX和AAO以及青椒的AAO活性瞬间下降明显,红提和青椒中脱氢抗坏血酸还原酶（DHAR）活性瞬间提高,随后迅速降低;而红提中单脱氢抗坏血酸还原酶（MDAR）活性提高,青椒中MDAR活性降低。[结论]在储藏过程中,DHAR的活性可能是影响ASA含量变化的重要因素。 相似文献
8.
目的 研究中药疏肝健脾解毒方对乳腺癌癌前病变肝郁证大鼠模型乳腺组织微血管密度（microvessel density, MVD）、血管内皮生长因子（vascular endothelial growth factor, VEGF）及乳腺组织结构的影响,探讨其防治乳腺癌的作用机制。方法 采用二甲基苯蒽灌胃及夹尾法制备乳腺癌癌前病变肝郁证大鼠模型,随机分为模型组（蒸馏水）、中药组（疏肝健脾解毒方10.35 g/kg）、三苯氧胺组（2.0 mg/kg）,另取10只为空白对照组,分别相应干预4周后,制备乳腺组织石蜡切片进行病理学观察,采用免疫组织化学方法及Western-blot法检测各组大鼠乳腺组织中MVD及VEGF表达情况。结果 免疫组化结果显示,与模型组比较,中药组及三苯氧胺组乳腺组织非典型增生现象减少,乳腺组织MVD及VEGF水平降低,差异有统计学意义（P<0.05）,中药组MVD及VEGF水平稍低于三苯氧胺组,差异无统计学意义（P>0.05）;Western-blot结果显示：与模型组比较,中药组及三苯氧胺组乳腺组织非典型增生现象减少,乳腺组织MVD及VEGF水平降低,差异有统计学意义（P<0.05）,中药组MVD及VEGF水平与三苯氧胺组比较差异无统计学意义（P>0.05）。结论 中药疏肝健脾解毒方可在一定程度上降低乳腺癌癌前病变乳腺组织非典型增生倾向,其机制可能与降低VEGF水平、抑制新生血管生成有关。 相似文献
9.
Perinatal dopamine-related drugs demasculinize rats 总被引：2，自引：0，他引：2
Administration of haloperidol, a common neuroleptic, to pregnant or lactating rats impaired the masculine sex behavior of their male offspring. Prenatal haloperidol did not affect testosterone concentrations in fetuses. Maternal administration of apomorphine, a dopamine agonist, and of alpha-methyl-p-tyrosine, an inhibitor of dopamine synthesis, also demasculinized male offspring. In both experiments other behaviors and developmental milestones were unaffected. Perinatal haloperidol, apomorphine, and alpha-methyl-p-tyrosine did not lower testosterone in adulthood. These drugs may act directly on neurons that control masculine behavior without lowering testosterone prenatally or in adulthood. 相似文献
10.
Positron emission tomography reveals elevated D2 dopamine receptors in drug-naive schizophrenics 总被引：12，自引：0，他引：12
D F Wong H N Wagner L E Tune R F Dannals G D Pearlson J M Links C A Tamminga E P Broussolle H T Ravert A A Wilson J K Toung J Malat J A Williams L A O'Tuama S H Snyder M J Kuhar A Gjedde 《Science (New York, N.Y.)》1986,234(4783):1558-1563
In postmortem studies of patients with schizophrenia, D2 dopamine receptors in the basal ganglia have been observed to be more numerous than in patients with no history of neurological or psychiatric disease. Because most patients with schizophrenia are treated with neuroleptic drugs that block D2 dopamine receptors in the caudate nucleus, it has been suggested that this increase in the number of receptors is a result of adaptation to these drugs rather than a biochemical abnormality intrinsic to schizophrenia. With positron emission tomography (PET), the D2 dopamine receptor density in the caudate nucleus of living human beings was measured in normal volunteers and in two groups of patients with schizophrenia--one group that had never been treated with neuroleptics and another group that had been treated with these drugs. D2 dopamine receptor densities in the caudate nucleus were higher in both groups of patients than in the normal volunteers. Thus, schizophrenia itself is associated with an increase in brain D2 dopamine receptor density. 相似文献
11.
为了探索‘保大麦20号’最佳及最有效的化肥施用量,在其他条件相同的情况下,设7个处理,进行大麦化肥减量试验。结果表明：（1）减少肥料用量10%的处理产量最高,减少肥料用量20%的处理其次,正常施肥水平的处理居第三位;（2）减少化肥用量20%的处理显著低于减少化肥用量10%的处理,但显著高于其他所有处理,其他减少化肥用量的处理随着化肥用量的减少产量随之减少;（3）投入产出比随着化肥用量的减少而增加,减少化肥用量10%、20%的处理收益较大;（4）减少化肥用量10%、20%的处理,穗实粒数及千粒重高于正常施肥水平的处理。在生产中,‘保大麦20号’可以减少化肥用量10%~20%,达到节本增效的目的。 相似文献
12.
Amphetamine: differentiation by d and l isomers of behavior involving brain norepinephrine or dopamine 总被引：4，自引：0，他引：4
d-Amphetamine is markedly more potent an inhibitor of catecholamine uptake by norepinephrine neurons in the brain than is 1-amphetamine, whereas the two isomers are equally active in inhibiting catecholamine uptake by the dopamine neurons of the corpus striatum. In behavioral studies, d-amphetamine is ten times as potent as 1-amphetamine in enhancing locomotor activity, while it is only twice as potent in eliciting a compulsive gnawing syndrome. This suggests that the locomotor stimulation induced by amphetamine involves central norepinephrine, while dopamine neurons play an important role in the induced compulsive gnawing behavior. Assessment of differential actions of d- and 1-amphetamine may be an efficient method to differentiate behaviors involving norepinephrine or dopamine in the brain. 相似文献
13.
【目的】最近在植物中发现了一类Ca2+传感蛋白--类钙调磷酸酶B亚基蛋白CBL（calcineurin B-like proteins）,CBL及其靶蛋白CIPK（CBL-interacting protein kinase）构成CBL/CIPK信号网络系统,在植物干旱、盐渍、低温等逆境胁迫应答中起重要作用。鉴定梨基因组中CBL家族基因成员,对其基因进化、结构与表达特征进行分析,为植物CBL基因功能分析与利用提供依据。【方法】通过生物信息学手段,结合梨基因组注释信息,鉴定梨CBL家族成员序列信息;利用MEGA6.0程序进行多序列比对、分类并构建系统进化树;利用per1程序、GSDS工具以及Clustal X软件进行基因结构与保守性分析;通过qRT-PCR技术进行多种非生物胁迫处理下PbCBLs表达分析。【结果】成功鉴定出7个CBL家族成员,基因结构预测表明PbCBL9含5个内含子,其余PbCBLs均含有7-8个内含子;预测的PbCBLs均含4个EF-hand功能域,且相邻EF-hand功能域之间氨基酸数目非常保守;通过系统发育树分析,将7个PbCBLs分为2类;qRT-PCR技术进行不同胁迫处理下杜梨叶片PbCBLs的表达分析,结果表明,在NaCl胁迫下,PbCBL1表达量6 h降至最低,24 h则明显升高;与之相反,PbCBL2和PbCBL3的表达量在6 h达最高,24 h最低;PbCBL4和PbCBL8表达量在3 h明显增加,随后表达量下降;PbCBL9表现明显的上调趋势,24 h达到最大;PbCBL10则在6 h表达量最高。10%（w/v）PEG6000胁迫处理下,PbCBL2、PbCBL4和PbCBL8表达量上调,PbCBL1表达量下调;PbCBL3、PbCBL9和PbCBL10表达量均在6 h最低,12 h和24 h较6 h明显升高,PbCBL3和PbCBL10于24 h表达量达到最高,而PbCBL9在12 h表达量最高。4℃低温处理下,PbCBL2、PbCBL4、PbCBL8表达量上调;而PbCBL1和PbCBL3表达量下调;PbCBL9和PbCBL10表达量表现上下波动的变化趋势,均在3 h有明显增加,随后显著降低。42℃高温胁迫处理下,PbCBL1、PbCBL3和PbCBL4表达量下调;PbCBL2表达量整体上调,6 h达到最高;PbCBL8、PbCBL9和PbCBL10总体呈现相同的变化趋势,在3 h表达量达到最高,随后明显下降。ABA处理下,PbCBL3和PbCBL10表达量下调,PbCBL2与PbCBL8表达量上调;PbCBL1在6 h表达量最高;PbCBL4和PbCBL9表达量呈现相似的变化趋势,3 h明显升高,随后下降,24 h时最低。【结论】成功鉴定的7个候选PbCBLs中,2个基因（PbCBL8和PbCBL9）受盐胁迫诱导表达,3个基因（PbCBL2、PbCBL4和PbCBL8）分别受干旱、低温与ABA诱导表达。PbCBL2在高温胁迫下被强烈诱导可能意味着其在高温应答中发挥重要作用。 相似文献
14.
Electrical activity may regulate a number of neuronal functions in addition to its role in transmitting signals along nerve cells. The hypothesis that electrical activity affects neurite elongation in sprouting neurons was tested by stimulating individual snail neurons isolated in cell culture. The findings demonstrated that growth cone advance, and thus neurite elongation, is reversibly stopped during periods when action potentials are experimentally evoked. A decrease in filopodial number and growth cone area was also observed. Thus, action potentials can mediate the cessation of neurite outgrowth and thereby may influence structure and connectivity within the nervous system. 相似文献
15.
Dopamine neurons play a key role in reward-related behaviors. Reward coding theories predict that dopamine neurons will be inhibited by or will not respond to aversive stimuli. Paradoxically, between 3 and 49% of presumed dopamine neurons are excited by aversive stimuli. We found that, in the ventral tegmental area of anesthetized rats, the population of presumed dopamine neurons that are excited by aversive stimuli is actually not dopaminergic. The identified dopamine neurons were inhibited by the aversive stimulus. These findings suggest that dopamine neurons are specifically excited by reward and that a population of nondopamine neurons is excited by aversive stimuli. 相似文献
16.
Reduced numbers of somatostatin receptors in the cerebral cortex in Alzheimer's disease 总被引：9，自引：0，他引：9
M F Beal M F Mazurek V T Tran G Chattha E D Bird J B Martin 《Science (New York, N.Y.)》1985,229(4710):289-291
Somatostatin receptor concentrations were measured in patients with Alzheimer's disease and controls. In the frontal cortex (Brodmann areas 6, 9, and 10) and temporal cortex (Brodmann area 21), the concentrations of somatostatin in receptors in the patients were reduced to approximately 50 percent of control values. A 40 percent reduction was seen in the hippocampus, while no significant changes were found in the cingulate cortex, postcentral gyrus, temporal pole, and superior temporal gyrus. Scatchard analysis showed a reduction in receptor number rather than a change in affinity. Somatostatin-like immunoreactivity was significantly reduced in both the frontal and temporal cortex. Somatostatin-like immunoreactivity was linearly related to somatostatin-receptor binding in the cortices of Alzheimer's patients. These findings may reflect degeneration of postsynaptic neurons or cortical afferents in the patients' cerebral cortices. Alternatively, decreased somatostatin-like immunoreactivity in Alzheimer's disease might indicate increased release of somatostatin and down regulation of postsynaptic receptors. 相似文献
17.
为改良酸性土壤、降低重金属活性和提高酸性土壤生产力,采用盆栽试验,探究硅钙钾镁肥(T1)、矿物调理剂A(T2)和矿物调理剂B(T3)降低土壤酸度的效果和对菠菜Cd累积的影响。结果表明:施用10 g/kg的矿物调理剂均能显著提高土壤pH,降低土壤交换性Al3+,使土壤酸度降低,矿物调理剂B的效果最优(T3)。施用矿物调理剂显著促进了菠菜的生长,T1、T2和T3处理使植株鲜重分别增加13.8、15.9和15.9倍。T2和T3处理使土壤DTPA-Cd含量分别降低41.6%和41.0%,菠菜植株Cd浓度分别降低48.9%和50.9%。此外,T2和T3处理也抑制了菠菜对Cd的累积,菠菜生物富集系数分别降低49.1%和50.9%。综上,以硅酸盐矿物、牡蛎壳粉和白云石为主要原材料制备的矿物调理剂在改良酸性土壤和降低镉的生物有效性方面具有更大的潜力。 相似文献
18.
Reduction of naturally occurring motoneuron death in vivo by a target-derived neurotrophic factor 总被引：7，自引：0，他引：7
R W Oppenheim L J Haverkamp D Prevette J L McManaman S H Appel 《Science (New York, N.Y.)》1988,240(4854):919-922
Treatment of chick embryos in ovo with crude and partially purified extracts from embryonic hindlimbs (days 8 to 9) during the normal cell death period (days 5 to 10) rescues a significant number of motoneurons from degeneration. The survival activity of partially purified extract was dose-dependent and developmentally regulated. The survival of sensory, sympathetic, parasympathetic, and a population of cholinergic sympathetic preganglionic neurons was unaffected by treatment with hindlimb extract. The massive motoneuron death that occurs after early target (hindlimb) removal was partially ameliorated by daily treatment with the hindlimb extract. These results indicate that a target-derived neurotrophic factor is involved in the regulation of motoneuron survival in vivo. 相似文献
19.
Stuber GD Klanker M de Ridder B Bowers MS Joosten RN Feenstra MG Bonci A 《Science (New York, N.Y.)》2008,321(5896):1690-1692
Using sensory information for the prediction of future events is essential for survival. Midbrain dopamine neurons are activated by environmental cues that predict rewards, but the cellular mechanisms that underlie this phenomenon remain elusive. We used in vivo voltammetry and in vitro patch-clamp electrophysiology to show that both dopamine release to reward predictive cues and enhanced synaptic strength onto dopamine neurons develop over the course of cue-reward learning. Increased synaptic strength was not observed after stable behavioral responding. Thus, enhanced synaptic strength onto dopamine neurons may act to facilitate the transformation of neutral environmental stimuli to salient reward-predictive cues. 相似文献
20.
Human red blood cells: prostaglandin E2, epinephrine, and isoproterenol alter deformability 总被引：3，自引：0，他引：3
The human red blood cell responds to prostaglandin E(2), epinephrine, and isoproterenol with a decrease in deformability. The maximum decrease is brought about by 10(-10)M prostaglandin E(2), 10(-9)M epinephrine, or 10(-7)M isoproterenol. The dose response curve is biphasic. The sensitivity of the red cell to prostaglandin suggests that this cell may be a primary target for prostaglandin action. These changes in response to vasoactive substances indicate that the red cell must be considered an active element in circulatory control. 相似文献