微囊化猪视网膜色素上皮细胞移植治疗帕金森病的实验研究(英文)

目的研究微囊化后的猪视网膜色素上皮细胞(retinal pigment epithelial,RPE)对帕金森病大鼠模型的移植疗效。方法原代培养RPE 并传代,高效液相色谱法测定培养液上清中多巴胺(dopamine, DA)和高香草酸(homovanillic acid, HVA)的含量,ELISA法检测脑源性神经营养因子(brain-derived neurotrophic factor, BDNF)和胶质细胞源性神经营养因子(glial-derived neurotrophic factor, GDNF)的含量。用高压静电成囊装置制备海藻酸钠-多聚赖氨酸-海藻酸钠微囊化细胞。6-羟基多巴胺(6-hydroxydopamine, 6-OHDA)毁损内侧前脑束 (medial fore-brain bundle,MFB)建立 SD 大鼠帕金森病模型。立体定向移植 RPE+ 微囊,检验旋转实验、免疫组化和脑内生化的变化。结果 RPE 培养上清液中DA、HVA、BDNF、GDNF 的含量稳定,微囊化后细胞长期存活,活性没有明显变化。6-OHDA毁损MFB建立大鼠帕金森病模型的成模率为83%。移植微囊化的RPE后有效率为33%。结论猪 RPE 体外培养生长旺盛,持续分泌 DA、BDNF 和 GNDF,微囊化不影响其分泌功能。RPE 移植对帕金森病大鼠有一定的治疗作用。     

Causal models of attention-deficit/hyperactivity disorder: from common simple deficits to multiple developmental pathways.

Until recently, causal models of attention-deficit/hyperactivity disorder (ADHD) have tended to focus on the role of common, simple, core deficits. One such model highlights the role of executive dysfunction due to deficient inhibitory control resulting from disturbances in the frontodorsal striatal circuit and associated mesocortical dopaminergic branches. An alternative model presents ADHD as resulting from impaired signaling of delayed rewards arising from disturbances in motivational processes, involving frontoventral striatal reward circuits and mesolimbic branches terminating in the ventral striatum, particularly the nucleus accumbens. In the present article, these models are elaborated in two ways. First, they are each placed within their developmental context by consideration of the role of person x environment correlation and interaction and individual adaptation to developmental constraint. Second, their relationship to one another is reviewed in the light of recent data suggesting that delay aversion and executive functions might each make distinctive contributions to the development of the disorder. This provides an impetus for theoretical models built around the idea of multiple neurodevelopmental pathways. The possibility of neuropathologic heterogeneity in ADHD is likely to have important implications for the clinical management of the condition, potentially impacting on both diagnostic strategies and treatment options.     

Aripiprazole blocks reinstatement of cocaine seeking in an animal model of relapse.

BACKGROUND: Aripiprazole (Abilify) is an atypical antipsychotic drug primarily characterized by partial agonist activity at dopamine (DA) D2 receptors and low side effects. Based on pharmacologic properties that include a stabilization of mesocorticolimbic DA activity, a pathway implicated in addiction, aripiprazole was tested for its ability to prevent relapse to cocaine seeking in rats. METHODS: We assessed the dose-dependent effects of aripiprazole on conditioned cue-induced and cocaine-primed reinstatement of drug-seeking behavior following chronic intravenous cocaine self-administration in an animal model of relapse. RESULTS: Aripiprazole potently and dose-dependently attenuated responding on the previously cocaine-paired lever during both reinstatement conditions, with slightly greater efficacy at reducing conditioned-cued reinstatement. Aripiprazole was effective at doses that failed to alter cocaine self-administration, food self-administration, reinstatement of food-seeking behavior, or basal locomotor activity, suggesting selective effects of aripiprazole on motivated drug-seeking behavior. CONCLUSIONS: These results in a relapse model show that aripiprazole can block cocaine seeking without affecting other behaviors. The D2 partial agonist properties of aripiprazole likely account for the blockade of reinstatement of cocaine-seeking behavior. Given its established efficacy and tolerability as a treatment for psychosis, aripiprazole may be an excellent therapeutic choice for reducing craving and preventing relapse in people with cocaine dependency.     

Brain uptake of radiolabeled N‐oleoyl‐dopamine in the rat

N‐acyl‐dopamines are a novel class of biologically active lipids that have recently been identified in the brain and have the potential to interact with neural signaling pathways. This study seeks to determine the ability of N‐oleoyl‐dopamine, a synthetic amide of oleic acid and dopamine, to cross the blood brain barrier. We determined the tissue content of radioactivity in selected brain regions, in a short‐run study design, following injections of [³H]N‐oleoyl‐dopamine (0.4 µCi) into the internal carotid artery in the rat. These results were compared with intracarotid injections of [³H]dopamine and with intravenous injections of both radiolabeled compounds. The level of radioactivity was determined using liquid scintillation and was expressed as the percentage of its total dose injected per gram of tissue. We found that the 15‐min brain uptake of radioactivity, with no distinct regional variations, amounted to about 6% following the intracarotid [³H]N‐oleoyl‐dopamine, which was a significant 3–4‐fold increase over that following similar administration of [³H]dopamine. Intravenous injections of [³H]N‐oleoyl‐dopamine gave a much smaller yield of radioactivity in brain tissue samples which was still severalfold greater than that for intravenous [³H]dopamine. Qualitative thin‐layered chromatography screening showed the presence of unchanged N‐oleoyl‐dopamine in the brain following injections. We conclude that N‐oleoyl‐dopamine has an appreciable ability to cross the blood‐brain barrier, which contrasts the limited transfer of dopamine alone. N‐oleoyl‐dopamine might exert physiological effects due to its known affinity for the central vanilloid receptors or to better satisfying the brain tissue demand for dopamine. The study suggests a potential pharmacological role for N‐oleoyl‐dopamine delivered exogenously in helping regulate the brain function. Drug Dev. Res. 60:217–224, 2003. © 2003 Wiley‐Liss, Inc.     

麻醉剂量羟甲芬太尼对大鼠脑内单胺递质及其代谢物含量的影响

麻醉剂量羟甲芬太尼对大鼠脑内单胺递质及其代谢物含量的影响金昔陆１唐琴梅金文桥周德和李桂芬池志强（中国科学院上海药物研究所，上海２０００３１）羟甲芬太尼（ｏｈｍｅｆｅｎｔａｎｙｌ，ＯＭＦ）是一种新的高选择性高亲和力μ阿片受体激动剂，在动物中能产生麻醉作...     

Transmitter Release Associated with Long-term Synaptic Depression in Rat Corticostriatal Slices

Using a corticostriatal slice preparation, we have recently shown that tetanic stimulation of the corticostriatal pathway produces long-term depression (LTD) of striatal excitatory synaptic transmission. In the present study we have analysed the relationship between LTD and the striatal release of different endogenous transmitters. Samples of perfusate were collected via a small cannula placed just above the surface of the striatal slice close to the recording electrode, and were analysed by HPLC. The high-frequency stimulation (100 Hz, three trains, 3 s duration, 20 s intervals) used to induce LTD caused a significant but transient increase in the release of both excitatory (aspartate and glutamate) and inhibitory (glycine and GABA) amino acid transmitters. Tetanic stimulation also produced a significant, but transient increase in the release of endogenous dopamine. We conclude that the tetanic stimulation of the corticostriatal pathway is able to induce a large but transient release of excitatory amino acids and of dopamine, whose participation in the induction of striatal LTD has been demonstrated previously. Moreover, the maintenance of this form of synaptic plasticity does not seem to require a sustained change in transmitter release.     

Pharmacological modulation of endogenous dopamine and DOPAC outflow from nucleus accumbens

The release of endogenous DA and DOPAC from nucleus accumbens slices were studied measuring net outflow of DA and DOPAC in the superfusate of static chambers, to analyze the correlation between DA and DOPAC outflows and identify which DA stores may serve as possible sources for DOPAC formation. Under resting conditions, or following stimulation with low (< 15 mM) KCl concentration, DOPAC outflow was greater than DA. When DA release was stimulated by higher (> 25 mM) KCl concentrations, DA outflow increased, proportionally more than DOPAC. In the virtual absence of Ca²⁺ in the Krebs solution DA outflow, induced by 25 mM KCl, was reduced to about 10%, while DOPAC outflow was only reduced to 45%. When the synthesis of DA was inhibited with -MPT, DA and DOPAC outflow were unchanged during the first stimulation period. During a second stimulation period, however, their outflow were significantly reduced. Nomifensine, a DA uptake inhibitor, increased the basal DA outflow by about 100%, but only blocked DOPAC basal outflow by about 25%. The 25 mM KCl stimulated DA outflow was not affected by Nomifensine, while the stimulated DOPAC outflow was reduced by about 50%. These results demonstrate that there is a weak correlation between the outflows of DA and DOPAC, suggesting a complex relationship between the mobilization of the different DA pools and DOPAC outflow. The formation of DOPAC from some of these pools, appear to be dependent on the stimulation levels and on the pharmacological manipulation of the tissue.     

Microstructure of the non-rapid eye movement sleep electroencephalogram in patients with newly diagnosed Parkinson's disease: effects of dopaminergic treatment.

We investigated non-rapid eye movement (non-REM) sleep in patients with newly diagnosed Parkinson's disease (PD) who had never previously received dopaminergic medication. There were no significant differences in the conventional sleep parameters between de novo patients with PD and a healthy control group, but the length of stage 1 sleep and the number of awakenings increased significantly upon administration of dopaminergic drugs. Analyzing the quantitative electroencephalogram (EEG), we observed a significant reduction in the low-delta frequency range and a nonsignificant increase in the sigma frequency range in de novo patients with PD. The dopaminergic medication also nonsignificantly reduced the low-delta and sigma frequencies, the latter to the level of the controls. Possible mechanisms that may account for the observed differences are discussed. It is suggested that Parkinson's disease as well as the application of dopaminergic drugs exerts a desynchronizing effect on the sleep EEG that is reflected in a disruption of sleep continuity.     

HIGH-LEVEL EXPRESSION OF RATD1A DOPAMINE RECEPTOR cDNA IN MOUSE FIBROBLASTLTK- CELLS BY n-BUTYRATE

1. In orefer to develop a simple, efficient system for the highlvel expression of dopamine recetors in eukaryotic cells, we have studied the effects of n-butyrate on the expression of rat D_1A dopamine receptor cDNA in mouse fibroblast LTK- cells as compared with those of n-butyrate on endogenous D₁ receptor levles in opossum kidney cells.
2. In the transfected LTK- cell mebranes with pRc/CMVD_1A receptor cDNA, a selective D₁ dopamine antagonist, [³H]-SCH 23390, exhibited a K_d of 0.9 ± 0.1 nmol/L and a B_max of 0.35 ± 0.05 pmol/mg protien (n = 5).
3. Addtion of n-butrate (2–10 mmol/L) to the culture medium for 48h dose-dependently increased the D_1A receptor level up to 1.5 ± 0.3 pmol/mg protien (n = 7), although the K_d values were not affected. The increase in receptor level was accompanined by an elevation of selective D₁ agoinist-induced adenyly cyclase activity.
4. In contrast, n-butyrate treatment (2–10 mmol/L) did not affect either endogenous D₁ receptor levels or fendoldopmainduced adenylyl cyclase activity in possum kidney cells.
5. These results sugges n-butyrate is a sueful tool for obtaining high-level expression of D_1A dopamine receptor cDNA in mouse fibroblast LTK- cells.