1.4 胃肠动力与相关受体

目前,胃肠学家们开始把注意力集中在胃肠动力上,因为维持人体生命活动的营养物质的吸收除靠消化液的作用外,更有赖于最佳的胃肠运动状态以实施混合、碾磨和运送食物的任务 .当神经递质、肽类激素、单胺类物质以及生长因子等调节分子对平滑肌细胞动力发挥其作用时,首先要与靶细胞上的特异受体结合.调节胃肠道的受体种类之多是惊人的,这与胃肠道具有多种类型的细胞及这些细胞具有多种调节因子有关.空腹和餐后胃肠运动模式的多样性及神经与肽类调控的复杂性要通过神经元和神经纤维以及平滑肌细胞上的受体才能产生效应.现就几种主要受体对胃肠动力调节及其相关药物的临床意义做一简介.     

Obestatin、Ghrelin与血糖调节

肥胖抑制素(obestatin)和生长激素释放肽(ghrelin)能互相拮抗,参与血糖的调节.其中obestatin与GPR-39(G-protein-coupled receptor 39)结合抑制摄食和胃肠排空、促进胰岛β细胞功能,影响胰岛素的分泌;而ghrelin与生长激素促分泌受体(GHSR1a)结合,促进食欲...     

胃肠动力与相关受体

目前 ,胃肠学家们开始把注意力集中在胃肠动力上 ,因为维持人体生命活动的营养物质的吸收除靠消化液的作用外 ,更有赖于最佳的胃肠运动状态以实施混合、碾磨和运送食物的任务。当神经递质、肽类激素、单胺类物质以及生长因子等调节分子对平滑肌细胞动力发挥其作用时 ,首先要与靶细胞上的特异受体结合。调节胃肠道的受体种类之多是惊人的 ,这与胃肠道具有多种类型的细胞及这些细胞具有多种调节因子有关。空腹和餐后胃肠运动模式的多样性及神经与肽类调控的复杂性要通过神经元和神经纤维以及平滑肌细胞上的受体才能产生效应。现就几种主要受体…     

SP-A及其磷脂代谢的发育性调节研究进展

SP-A的发育性调节及其对磷脂代谢的影响相当复杂 ,不同胎龄的肺Ⅱ型细胞SP AmRNA及蛋白质表达水平不同 ,主要受顺式作用元件和甲状腺转录因子 1(TTF 1)、蛙皮素样肽 (BLP)的调节 ,且人SP A与其他动物在基因结构和调节序列方面存在明显差异。随着SP A受体成熟SP -A发挥多种不同的效应 ,SP A受体发育水平不同与SP A对肺Ⅱ型细胞磷脂代谢调节明显相关     

胃肠肽在应激所致结肠动力紊乱中的可能作用

胃肠肽在应激所致结肠动力紊乱中的可能作用桂先勇（第三军医大学三院消化科）潘国宗，柯美云，陆国钧（北京协和医院消化内科）大多数胃肠肽是胃肠运动调节机制中的重要成分。应激所致结肠运动异常是否涉及某些胃肠肽的变化，尚乏研究。本工作旨在探讨应激后胃肠肽释放量...     

胃泌素研究进展:从受体到药物

胃泌素是一种非常重要、具有激素(分布于胃肠系统)和神经肽(分布于神经系统)双重功能的肽类。胃肠道胃泌素已不仅局限于它的促泌酸作用,调节细胞生长及营养作用被认为是胃泌素最重要的功能。胃泌素受体拮抗剂在胃肠道肿瘤、消化性溃疡、高胃泌素血症等的应用价值受到高度重视。     

甲状腺滤泡旁细胞的研究进展

甲状腺滤泡旁细胞是甲状腺中产生降钙素的细胞。但作为ＡＰＵＤ系的甲状腺滤泡旁细胞也有分泌多种调节肽的功能。本文对甲状腺滤泡旁细胞分泌调节肽的种类，分泌调节肽的基因机制以及调节肽的作用机制的研究进行综述     

大鼠背根神经节肽能和非肽能小型神经元均表达GABA_B受体——脊髓水平突触前痛觉调节机制的证据(英文)

已知痛觉传递调制途径之一是通过背根神经节中的小型神经元的突触前代谢型GABAB受体介导。为了探讨肽能和非肽能2个亚群的小型背根神经节(DRG)神经元是否在痛觉调制过程中发挥同等作用,本实验用免疫荧光组织化学法和激光共聚焦显微镜技术观察了DRG内肽能和非肽能2个亚群的小型神经元中GABAB受体的表达。结果显示:92%的肽能和90%的非肽能亚群的小型神经元均表达GABAB受体,这些受体存在于2个亚群的胞体及其分布在脊髓背角特定板层的中枢突中。该结果表明在痛觉调制过程中,肽能和非肽能2个亚群的小型DRG内神经元在脊髓水平发挥类似作用,但作用于脊髓背角的不同板层。     

血管活性肠肽的免疫调节作用

血管活性肠肽是一种神经肽 ,又是一种小分子免疫活性肽。随着与相应血管活性肠肽受体的cDNAs被克隆和表达 ,对血管活性肠肽的免疫学作用也有了更深入的认识。血管活性肠肽通过影响细胞因子的产生、调节炎症反应、影响胸腺细胞的分化、调节Th细胞应答来参与免疫自稳的调节 ,并可抑制T淋巴细胞的凋亡、抑制T细胞介导的细胞毒作用     

成骨细胞表面不同神经肽受体的表达

背景：大量研究表明神经因素可调节骨代谢,迄今为止已发现5种神经肽参与骨代谢过程。 目的：观察正常人成骨细胞表面不同神经肽受体的表达。 方法：分别以降钙素基因相关肽、酪氨酸羟化酶、P物质、神经肽Y的单克隆抗体进行免疫组化染色,观察各种肽类受体在成骨细胞表面的表达情况。另外,利用计算机图像分析系统对染色灰度进行半定量分析。 结果与结论：正常人成骨细胞表面有神经肽Y、P物质、酪氨酸羟化酶、降钙素基因相关肽受体表达,这些因子可以通过与相应的受体结合影响细胞生物学特性。不同因子免疫组化染色的灰度值由小到大依次为神经肽Y、降钙素基因相关肽、酪氨酸羟化酶、P物质,神经肽是成骨细胞活性的重要调节因子。     

Level of functioning of siblings and parents of probands of varying degrees of retardation

A further analysis of already published data supports the position that retardates of low ability level less frequently have retarded siblings, retarded parents, and parents low in occupational level than do retardates higher in ability level. The analysis supports the position that there are two types of retarded individuals, persons retarded as a result of gene or chromosomal anomalies, brain injury, etc., who more frequently occur in the lower-level retardate group, and persons whose retardation represents polygenic segregation, who more frequently occur in the higher-level group.     

Modes of Inheritance of Errors of Refraction

Eighteen families in which both parents had refractions within the range of +4·0 D to −4·0 D and axial lengths seen in emmetropia (22·3-26·0 mm) showed coefficients of correlation of the order 0·5 indicative of polygenic inheritance. Such coefficients were seen for axial length (0·407) and for the cornea (0·487), but not for the lens (which is known to be yoked to the axial length). No such coefficients were seen in 19 families in which one of the parents had axial length outside the emmetropic range (nine families with long axes and 10 with short axes).

The pattern of polygenic inheritance for emmetropia (completely correlated optical components) and errors of refraction up to 4·0 D (inadequately correlated components: correlation ametropia) follows that seen in stature and other measurable characters. In contrast the high refractive errors with their abnormal axial lengths (component ametropia) are—like the extremes in stature—pathological anomalies with monofactorial inheritance.

     

Aspects of the problem of direct introduction of Standards of International Organizations

Editorial note. This article is published as part of a discussion. Particular issues of the article are disputable. First of all, this concerns the so-called “folder” method of introduction of international standards for medical devices to domestic medical practice (i.e., by direct translation of the standards and their publication as standardizing documents). Nevertheless, at least one of the problems, the problem of coordination between domestic state standards for medical devices and international recommendations of ISO and IEC, is undoubtedly of topical importance. Advancement of new health service legislation which is to be approved by law-makers will definitely introduce corrections into the present situation. The Editorial Board of Meditsinskaya Tekhnika believes this article will lessen these problems and to be welcomed by readers.