水盐负荷改变时分泌心房钠尿肽的心房特殊颗粒数目与其钙含量的相关变化

本文报道大鼠水盐负荷时,其心房特殊颗粒（ＡＳＧ）的数目及钙含量发生相关变化。给大鼠禁水５ｄ或饮２％ＮａＣｌ液４ｄ造成水盐负荷,用电镜形态计量法计数ＡＳＧ,以反映心房钠尿肽（ＡＮＰ）的分泌水平,电镜Ｘ射线显微分析法测定ＡＳＧ中钙、硫含量及肌质同终末池（ＴＳＲ）中钙含量。结果显示,禁水引起ＡＮＰ分泌减少时,ＡＳＧ的数密度增加（６．０２±２．３０增至９．９７±３．２１个／μｍ３）,同时伴有钙含量增加（６４±１６增至９２±１８ｍｍｏｌ／ｋｇ）;饮盐水引起ＡＮＰ分泌增加时,ＡＳＧ的数密度减少（６．０２±２．３０减至２．９６±１．６２个／μｍ３）,巨伴有钙含量减少（６４±１６减至３８±２２ｍｍｏｌ／ｋｇ）,但水盐负荷对ＴＳＲ中钙浓度无任何影响。据此推论ＡＳＧ作为细胞内钙库,借某种机制调控其中钙的释放而参与ＡＮＰ的刺激分泌耦联过程。     

感染日本血吸虫小鼠心房特殊颗粒的形态学观察和定量分析

小鼠感染日本血吸虫尾蚴后第２８天,右心耳心房特殊颗粒数目显著减少,且多见膜溶解、断裂,半月形排空和颗粒膜与横管膜及肌膜靠近、融合及颗粒向横管腔及肌膜下突出的现象。心肌细胞内线粒体有肿胀、基质变浅及部分嵴断裂现象。感染组小鼠右心耳心房特殊颗粒的体密度（０．０３２３±０．００２９μｍ３／μｍ３）、面数密度（０．８６４７±０．０６９２μｍ－２）、数密度（３．２３６３±０．１１１４μｍ－３）及颗粒平均直径（０．２６７１±０．０２０７μｍ）均显著小于对照组的０．０９７１±０．０１２７μｍ３／μｍ３、１．９２１±０．１１４５μｍ－２、０．２１８９±０．０８６６μｍ－３和０．３１０８±０．０１９５μｍ。本文阐述了日本血吸虫感染后,促进心房特殊颗粒释放增加。     

胰岛素诱导低血糖大鼠心房肌细胞特殊颗粒的形态计量和心房利钠肽免疫组织化学研究

通过形态计量学和免疫组织化学方法发现胰岛素诱导低血糖大鼠心房肌细胞核周区特殊颗粒（ＡＳＧ）的体密度、面数密度和数密度及平均直径均高于对照组（Ｐ＜０．０５）,但高尔基复合体各参数与对照组比较没有差别（Ｐ＞０．０５）。实验组的心房利钠肽（ＡＮＰ）的免疫反应强度比对照组强（Ｐ＜０．００１）。提示胰岛素诱导低血糖对心房利钠肽的释放具有抑制作用,表明ＡＮＰ作为生理和病理调节递质与代谢刺激相拮抗。     

应急大鼠肾上腺髓质嗜铬细胞颗粒数目与其钙含量的关系

采用电镜细胞立体形态计量法及电镜Ｘ射线显微定量分析术,对制动应急大鼠的肾上腺髓质细胞内嗜铬颗粒数密度和颗粒内Ｃａ浓度变化进行测量。结果显示,两者在制动过程中均呈进行性下降,但颗粒内钙浓度的下降快于颗粒数目的减少（Ｐ〈０．０１）。该结果支持颗粒内钙释放入胞质,参与胞质内游离钙浓度的升高,进而激发颗粒胞吐的假设,为主宰嗜铬颗粒是一种细胞内钙库并参与细胞分泌提供了实验依据。     

人胚心肌纤维中心房特殊颗粒的分布及心钠素的免疫组化研究

收集胚胎标本共24例（经临床证实孕妇无心血管疾病）,用透射电镜观察各胎龄心脏各部位心肌纤维中心特殊颗粒（ASG）分布及含量变化,同时结合免疫组织化学技术对心脏各部位心肌纤维内心钠素的表达进行研究。结果表明,胚第5周时,心肌纤维便有ASG出现,随着胎龄的增长,心房与心耳的颗粒数量逐渐增多。而心室的颗粒数量却逐渐减少,在同一胎龄,心房内的颗粒数量多于心室,心耳ASG多于心房,免疫组织化学的研究结果表明,胚第7周时,心房与心耳内可出现心钠素样免疫反应阳性的心肌细胞,其阳性反应的变化规律与ASG的变化规律一致。心室中未发现阳性反应。     

糖尿病大鼠心房肌细胞心房特殊颗粒和心房肽免疫反应强度的观察

本研究运用透射电镜及立体计量学方法结合免疫组化技术对糖尿病大鼠右心耳肌细胞心房特殊颗粒(ASG)和心房肽(ANP)免疫反应强度进行了观察和定量研究.实验动物为体重150～250克之间的SD大鼠,糖尿病的诱导采用四氧嘧啶(150mg/kg)右腹股沟区皮下注射.电镜超微结构发现糖尿病未治疗组均出现线粒体肿胀、肌原纤维缩短等病理性改变.ASG膜溶解、排空等现象多见,ASG体密度明显减少.免疫组化分析表明糖尿病未治疗组心肌细胞ANP免疫反应强度减弱.胰岛素治疗组各指标与对照组相比均无显著差别.     

自发性高血压大鼠右心耳肌细胞特殊颗粒的形态分析和ANP免疫反应强度的观察

本研究运用透射电镜及形态计量学方法结合免疫组织化学技术对成年自发性高血压大鼠（ＳＨＲ）的右心耳肌细胞心房特殊颗粒（ＡＳＧ）和心房利钠肽（ＡＮＰ）的免疫反应强度进行了观察和定量研究。成年自发性高血压大鼠的心肌细胞内,ＡＳＧ数目增加,直径增大,高尔基复合体发达;线粒体轻度肿胀,部分嵴溶解断裂,部分内质网扩张,糖原颗粒增多。ＡＮＰ免疫反应增强与ＡＳＧ数目的增加一致。提示自发性高血压大鼠ＡＮＰ的合成和释放均增加,以维持机体在高血压状态下血压的平衡和内环境的稳定。     

细胞内分布克隆--一种新的功能性基因克隆方法

明确蛋白质的细胞内定位对了解蛋白质的功能有很强的提示作用。近年来随着对蛋白质细胞内定位信号和转运机理的深入了解,建立了根据蛋白质分子在细胞内的特殊定位进行快速功能性基因克隆的方法,即细胞内分布克隆,其筛选基因可以是形态学的,也可以是功能上的,利用这些方法克隆了许多定位于特定细胞器但功能未知的蛋白基因,本文对这些方法及其进展进行综述。     

SPECIFIC GRANULES IN ATRIAL MUSCLE CELLS

Large populations (up to 600/cell) of spherical, electron-opaque granules ~0.3 to 0.4 µ in diameter are characteristically found in muscle fibers of mammalian atria. They are absent in muscle fibers of the ventricles. The granules are concentrated in the sarcoplasmic core and occur in lesser numbers in the sarcoplasmic layers between myofibrils and under the plasma membrane. Their intimate association with a central voluminous Golgi complex and the frequent occurrence of material reminiscent of the granular content within the cisternae of the Golgi complex suggest that the latter is involved in the formation of the atrial granules. Atrial granules are larger and more numerous in smaller species (rat, mouse), and generally smaller and less numerous in larger mammals (dog, cat, human); they are absent from the atrial fibers of very young fetuses (rat) but are present in those of newborn animals. A small population of bodies containing glycogen particles and remnants of the endoplasmic reticulum and mitochondria occurs in the sarcoplasmic cores of atrial as well as ventricular muscle fibers in the rat; they contain acid phosphatase and thus appear to be residual bodies of autolytic foci. Their frequency increases with the age of the animal. Typical lipofuscin pigment granules, which are known to contain acid phosphatase and are found in the sarcoplasmic cores in old animals (cat, dog and human), are presumed to arise by progressive aggregation and fusion of small residual bodies.     

SH－SY5Y细胞胞内钙库特性研究

运用单细胞显微荧光测量技术测量了单个ＳＹ－ＳＹ５Ｙ细胞内游离钙离子浓度的变化。首次报道了ＳＨ－ＳＹ５Ｙ细胞内存在毒蕈碱敏感而非咖啡因敏感的钙库,并研究了它的动力学特征。     

SH－SY5Y细胞胞内钙库特性研究

运用单细胞显微荧光测量技术测量了单个ＳＨ—ＳＹ５Ｙ细胞内游离钙离子浓度的变化。首次报道了ＳＨ—ＳＹ５Ｙ细胞内存在毒蕈碱敏感而非咖啡因敏感的钙库,并研究了它的动力学特征。Ｎ￣￣Ｃ￣ｈｅｔｗＭａｄＵｇｈ＊ＴＯｗｈｏｍＣｂ￣ｐｏｎｄｅｎｅｅｓｈｏｕｌｄｂｅ￣．     

不同生理状态对大鼠右心耳肌细胞特殊颗粒的影响──形态学和计量学研究

本文通过电镜观察和立体计量学方法,研究迷走神经和肾上腺素对ＳＤ大鼠右心耳肌细胞特殊颗粒（ＳＧ）的影响。结果是迷走神经切除组ＳＧ的体密度（ＶＶ）、颗粒平均直径（Ｄ）明显小于对照组（Ｐ＜０．００１）,肾上腺素组ＳＧ的ＶＶ、Ｄ、数密度（Ｎｖ）也明显小于相应对照组（Ｐ＜０．００１）。结果提示迷走神经对心钠素的释放是抑制作用,肾上腺素对心钠素的释放是促进作用。本研究还为ＳＧ的产生与分型,心钠素的多种释放方式提供了形态学资料。     

MITOCHONDRIA AND THE CONTROL OF INTRACELLULAR CALCIUM

1.Because the calcium (Ca) ion is intimately associated with so many biochemical and physiological phenomena, it is fundamental to understand how intracellular Ca is maintained and controlled. This review draws attention to the vital role played by mitochondria in controlling intracellular Ca and describes how transport of the ion into and out of mitochondria may itself be controlled. 2.The heterogeneous distribution of Ca is a property of most, if not all cells. This arises because the ion binds strongly to a variety of biological compounds, especially those containing oxyanions, which themselves have a heterogeneous distribution in cells, but mostly because of the existence in the cell of specific Ca-ion transport systems. 3.Although the concentration of total Ca in the cell may be quite high, a very large proportion of it is bound and non-diffusible; a small fraction is diffusible but unionized. The proportion of Ca that is ionized is probably much less than I% of the total 4.The mechanisms by which Ca is transported into and out of the mitochondrial matrix are discussed. Inward movement of the ion occurs in response to the membrane potential (negative inside) generated by respiration. The process is carrier-mediated and exhibits characteristics such as substrate specificity, high affinity for Ca, satur-ability, cooperativity, stimulation by permeant anions and is specifically inhibited by low concentrations of Ruthenium Red and lanthanum. The properties of the Ca carrier are geared therefore to facilitate rapid inward movement of Ca into the mitochondria. Such a carrier system is found in mitochondria isolated from a wide variety of tissues and species. 5.Ionized Ca appears not to be distributed across the inner mitochondrial membrane according to the Nernst equation, so the possibility exists that the ion is transported as Ca/H⁺ antiport or as Ca/anion symport. Alternatively, an efflux system coupled to inward movement of a cation may serve to prevent the [Ca ion]_in/[Ca ion]_out from attaining equilibrium. These components together contribute to a Ca-translocation cycle that permits Considerable flexibility in the overall control of Ca flux. 6.Evidence for Ca cycling in mitochondria is presented and the influence of physiological agents such as Mg, phosphoenolpyruvate, inorganic phosphate and adenine nucleotides, on the influx and efflux components are discussed in some detail. Moreover, various hormones administered in vivo are able to induce changes in mitochondrial Ca cycling. One important feature that emerges from this collection of data is that the ability of mitochondria to retain Ca is associated with their ability to retain also their adenine-nucleotide complement. 7.Various lines of research provide convincing evidence in support of the view that mitochondria play a major role in controlling cell Ca in vivo. Especially significant are the observations that the ‘activity’ of mitochondrial Ca transport can change during development in both insect and mammalian tissue, can depend on the hormonal status of the tissue and undergoes a permanent change in certain tumour cells. 8.Finally, consideration is given as to how the mitochondrial Ca transport system is able to modify Ca-sensitive enzyme activities by regulating the Ca concentration in specific environments. Some biological activities that might be susceptible to such control are discussed.     

热暴露大鼠心肌细胞钙稳态及其调节机制的研究

本文观察了离体成年大鼠心室肌肌质网、线粒体Ｃａ＾２＋－ＡＴＰ酶活性和总钙含是到及原代培养乳腺心肌细胞＾４６Ｃａ摄取、活性钙调素相对含量、胞浆内游离钙浓度在不同温度热暴露４０ｍｉｎ后的变化。结果表明：热暴露后,心肌奖浆、肌质网及线粒体中的Ｃａ＾２＋－ＡＴＰ酶活发表 所下降,心肌肌质网及线粒体中的总钙含量亦有降低趋势,心肌细胞活性钙调素相对含量显著下降,＾４６Ｃａ摄取量及胞浆内游离浓度显著升高。提示,