998 resultados para Récepteur aux cannabinoïdes CB2


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Early illustrated book about fish, fishing and fisheries by one of the preeminent scientific investigators of the French enlightenment. This work deals extensively with the species of fish found in Europe and beyond, their habits and habitats, techniques and equipment used in fishing and fish processing, and many other aspects of these endeavours. Roughly 185 engraved plates illustrate the text. The scans for this version come from 3 volumes bound in two parts in folio.

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Abundance and species variations of the macrofauna associated with the roots of Pistia stratiotes of Ayamé II lake and Comoé river were studied during one year. Samples of plants were collected by hand once a month within a sampler of 1 m2 of surface.

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The gasteropods sampling from roots system of floating plants Pistia striatiotes, Salvinia molesta, Salvinia nymphellula, Eichhornia crassipes, show that those biotopes are not azoic. We collected 18 species of gasteropods. The mapping of the species collected has been realized and permitted to identify three regions and three groups of gasteropods: 1 The gasteropods collected between 5° and 7° South; 2 The gasteropods collected between 8° and 10° North; 3 The widespread gasteropods. The species distribution according to latitude shows that 90% of species are found between 5° and 6° South, 65% between 6° and 7° South, 20% between 7° and 8°, 20% between 8° and 9° and 15% between 9° and 10° North.

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Geryon quinquedens is present along the West African continental slope at depths from 300 to 1000 m, on silt-clay sediments. Geryon is a cold and rather poorly oxygenated water loving species. It is easily caught by traps as it is a scavenger and predatory crustacea. In a given area its distribution does not appear to be homogeneous: for example, densities of red crabs are higher in the eastern and western region of Côte d'Ivoire than in the central zone. Similar observations can be made off Congo, Angola and United States. It can be assumed that there is a relation between the abundance of Geryon and the productivity level of the area. Geographical variations of sex ratio are suspected to be correlated with the density distribution. Males and females have not the same bathymetric distribution: females are only common in the shallower waters (300-500 m) whereas males are present in the whole biotope. Seasonal migrations occur down and up the slope in both the sexes and are certainly related to the reproductive biology. Knowledge of the reproductive biology is also necessary to understand fishing-trap catch rate: egg maturation extends over several months and ovigerous females are exceptionally caught by traps; males also are less available during the same period (March to August) when migrations are less important; in this period, mean size increases and probably this happens at the end of a moult. From September to February the catch-rates increase. Growth is slow compared with other littoral Guinean Crustacea (Peneides). Females become sexually mature at a size of 80 mm (carapace width): modification in the allometric relations of abdomen and carapace are then conspicuous.

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A computer program has been written in order to generate a population of fishes following a Von Bertalanffy growth curve with a random Gaussian variability for birth dates and growth parameters K and L ∞. Standard deviations for these 3 parameters are chosen separately for each run. Fishing and natural mortalities are applied to this population. Using as an input parameters usually taken for yellowfin in the eastern Atlantic, the simulation suggests a standard deviation between 1 and 2 months for the birth dates in this population. It also indicates that increasing levels of fishing mortalities must produce a better agreement between age and length for the larger fish.

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吗啡是临床常用的镇痛药物之一,通过模拟内源性抗痛物质脑啡肽的作用,激活中枢神经阿片受体而产生强大的镇痛作用。吗啡属于阿片类生物碱,为阿片受体激动剂,是目前我国主要的毒品成瘾类型之一,对人民生命健康危害极大。目前我国登记在册的吗啡成瘾者约有100万,每年导致的直接经济损失超过1000亿元。因此吗啡成瘾机制的研究以及治疗,是目前神经疾病的研究重点之一。 吗啡成瘾与其结合的受体有关。吗啡除结合阿片受体外,也可能结合大麻素受体,现发现体内有两种大麻素受体的存在:CB1受体和CB2受体。大麻CB1、CB2受体都是G蛋白耦联受体。其中CB1受体主要位于脑、脊髓与外周神经系统中,脑内CB1受体主要分布于基底神经节(黑质、苍白球、外侧纹状体)、海马CA锥体细胞层,小脑和大脑皮层。因此推测大麻CB1受体的功能可能与成瘾、记忆、认知、运动控制的调节有关。而大麻CB2受体主要分布于外周组织,如脾脏边缘区、扁桃体等,它的这种分布可能与免疫抑制作用有关。近来的研究发现大麻CB2受体在中枢神经系统也有分布,目前对其在此分布的功能不明确,推测可能与成瘾、抑郁症等神经类疾病有密切关系。 在药物成瘾导致的精神依赖作用中,奖赏效应是各种药物成瘾的药理学基础。中脑—边缘系统((mesolimbic dopamine system,MLDS)是药物奖赏效应的神经解剖学基础。目前认为内源性大麻素所起的药理作用与多巴胺能和阿片能的神经传递有密切的关系。因此推断大麻素CB1受体与慢性吗啡成瘾有密切关系,至少是部分参与到慢性吗啡成瘾过程中。 相较于较多的关于大麻CB1受体的研究,有关大麻CB2受体的研究很少。尽管近来证实大麻CB2受体也分布于中枢神经系统,但在慢性吗啡成瘾时,大麻CB2受体表达的改变仍不清楚。在本项目中,我们将对慢性吗啡成瘾动物通过分子生物学、蛋白质化学、免疫组织化学的方法,探讨大麻CB2受体在中枢神经系统的分布和表达,以及大麻CB2受体在吗啡成瘾中可能的作用。 吗啡对免疫系统有抑制作用, 包括抑制淋巴细胞增殖, 减少细胞因子的分泌,减弱自然杀伤细胞(NKC)的细胞毒作用。现已证实激活周围神经系统的CB2受体可诱导IL-4的生成,从而影响阿片μ型受体的转录。此发现提供了内源性大麻系统-阿片系统-免疫系统之间存在相互作用的关系。然而,吗啡吸食是否通过CB2受体从而导致免疫功能的抑制,现在还没有直接证据,在本实验中我们将探讨CB2受体与吗啡成瘾导致免疫功能的改变有关。 实验结果显示(1)应用RT-PCR法,检测到大麻素受体CB1在慢性吗啡成瘾大鼠的皮质和海马处mRNA表达水平与对照组大鼠有明显不同。(2)应用western免疫印迹法,检测到大麻素受体CB1在慢性吗啡成瘾大鼠的皮质,海马和脑干处蛋白表达水平与对照组大鼠有明显不同。在脑干处,虽然mRNA表达水平无变化,但蛋白质的表达水平上升。(3)应用免疫组化检测到大麻素受体CB1在大鼠的皮质,海马,脑干,小脑处都广泛分布。(4)应用RT-PCR法,检测到大麻素受体CB2在慢性吗啡成瘾大鼠的皮质,海马,脑干处mRNA表达水平与对照组大鼠有明显不同。(5)应用western免疫印迹法,检测到大麻素受体CB2在慢性吗啡成瘾大鼠的皮质,海马,脑干蛋白表达水平与对照组大鼠有明显不同。且蛋白质的表达改变趋势与mRNA表达水平的改变相似。(6)应用免疫组化法检测到大麻素受体CB2在大鼠的皮质,海马,脑干,小脑处都广泛分布。但数量明显少于大麻CB1受体。(7)应用直接ELISA法,检测到慢性吗啡成瘾大鼠的血清与对照组大鼠的血清比较,IgM表达下降;IgG表达上升。 实验结果提示大麻受体CB1和CB2 很可能在慢性吗啡成瘾过程起着重要的作用,至少是部分参与到慢性吗啡成瘾的过程中。因为大麻素受体CB1和CB2都属于G 蛋白耦连受体,长期持续使用吗啡,其表达的变化可能会导致cAMP信号通路的上调;提高了腺苷酸环化酶(AC)和蛋白激酶A(PKA)的活性从而激活下游相关基因的表达最终导致成瘾。此外大麻素受体CB1和CB2表达的变化可能与慢性吗啡成瘾后免疫功能的改变有相关性。 通过以上的的实验结果,可以得到以下的结论:(1)我们验证了大麻素受体CB1在慢性吗啡成瘾大鼠的皮质,海马和脑干处mRNA和蛋白质表达水平与对照组大鼠有明显不同,且大麻CB1受体在大鼠中枢神经系统中广泛大量分布,表明大麻素受体CB1很可能在慢性吗啡成瘾过程中起着重要的作用,至少部分参与到慢性吗啡成瘾的过程中。(2)我们第一次证实了大麻素受体CB2在吗啡成瘾大鼠的皮质,海马和脑干处mRNA和蛋白质表达水平与对照组大鼠有明显不同,且大麻CB2受体在大鼠中枢神经系统中少量广泛分布。表明大麻素受体CB2很可能在慢性吗啡成瘾过程中起着重要的作用,至少部分参与到慢性吗啡成瘾的过程中。(3)同时我们发现大麻素受体CB1和CB2在大鼠脑组织中广泛表达,表明内源性大麻系统有可能广泛的参与各种神经疾病,很可能成为治疗的新靶点。(4)最后我们发现慢性吗啡成瘾大鼠血液中IgM表达下降;IgG表达上升,表明慢性吗啡成瘾对机体的免疫功能有广泛的调节作用。慢性吗啡成瘾大鼠血清CB2受体mRNA表达上升。我们证实了大麻受体CB2可能正是把神经系统和免疫系统相联系的一个靶点。

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Première edition revue, corrigée, et précédée d'une Préface à la Mosaïque, dans le plus nouveau goût.

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Etude de la réutilisation des protocoles (c'est-à-dire des premières pages des rouleaux de papyrus, qui portent un «timbre fiscal») dans l'Égypte byzantine et arabe