大鼠松果体分泌物释放到蛛网膜下隙脑脊液途径的电镜研究

为探讨松果体分泌物在细胞外转运到蛛网膜下隙脑脊液途径的结构基础,本研究运用透射电镜技术对成年大鼠松果体浅部进行了观察。结果显示:(1)大鼠松果体毛细血管为有孔型(孔径50nm),借基膜与宽阔的血管周隙分隔;(2)松果体细胞借基膜与结缔组织间隙分隔,松果体细胞之间形成与松果体囊结缔组织间隙及血管周隙相通的细胞间小管;(3)松果体囊表面为扁平上皮,上皮下为疏松结缔组织间隙,其内可见松果体细胞的胞体和突起。囊上皮细胞间存在瓣膜样连接(叶瓣间宽处可达1μm)和囊上皮孔(2.5μm)。以上结果提示,松果体细胞表面可分为结缔组织间隙面、连接面和细胞间小管面三个功能面,松果体分泌物可能通过血管周隙-细胞间小管-松果体囊结缔组织间隙-囊上皮瓣膜样连接或囊上皮孔,释放入蛛网膜下隙脑脊液中转运。     

猴松果体分泌物释放入脑脊液主要途径的结构基础电镜研究

目的 探讨松果体分泌物直接释放入脑脊液途径的开矿学依据,方法 采用常规及ＮaＯＨ 消蚀法电镜样品制备技术,对成年日本猴松果体及其补囊进行了扫描和航向电镜观察。结果松果体囊同一层扁平上皮细胞和上皮下结缔组织构成。在面对蛛网膜下隙的囊上皮细胞和细胞间存在许多上皮孔;上上结缔组织什入要体形成小叶间隔,浆松果体分隔为许多实质小叶。松果体结缔组织的主要成分为胶原纤维;实质小叶由大量松果体细胞和少数胶质细胞组成     

大鼠松果体组织结构的增龄变化

目的；观察大鼠松果体组织结构的增龄变化。方法：应用计算机图像分析和透射电镜研究了幼年，青年和老年大鼠松果体。结果：随着年龄增加，大鼠松果体的体积依次增大，每个视野内松果体实质面积和实质细胞数减少，间质增生，衰退的松果体暗细胞在各年龄组大鼠松果体中均非常少见，实质细胞间存在与血管周隙和神经胶质细胞周隙相通的细胞间小管。结论：随着年龄增加，大鼠松果体的实质细胞总数和松果体细胞总数下降或衰退的暗细胞总灵敏增加，从而导致松果体分泌功能下降的观点，值得商榷，大鼠松果体分泌物可能通过细胞间小管-血管周隙和神经胶质细胞周隙-囊上皮孔而直接释放到蛛网膜下隙的脑脊液中，结缔组织增生可阻碍其释放。     

神经垂体多肽激素分泌颗粒释放形式和转运途径的形态学研究

目的探讨神经垂体多肽激素分泌颗粒的释放形式和在细胞外正常转运途径的结构基础。方法对大鼠神经垂体进行光镜、透射电镜和扫描电镜观察。结果神经垂体主要由无髓神经纤维、垂体细胞及富含毛细血管的结缔组织组成。毛细血管内皮为有孔型(50nm)，外有基膜与血管周隙分隔。完整的大型膜包分泌颗粒(100～300nm)不仅大量存在于无髓神经纤维内，而且也见于血管周隙内。垂体囊由单层扁平上皮细胞和上皮下结缔组织构成，囊上皮细胞间存在许多不规则的囊上皮孔(2～5μm)，上皮孔附近经常可见分泌颗粒。结论这些结构特征提示，神经垂体多肽激素或分泌颗粒的释放形式，存在一种连同颗粒被膜的整体释放；释放入血管周隙内的多肽激素或分泌颗粒，更易经组织间隙、囊上皮孔进入脑脊液发挥旁分泌作用，而非直接通过毛细血管壁进入血液。     

松果体分泌物释放入脑脊液主要通路的常规及消蚀法扫描和透射电镜研究

哺乳动物的松果体,为脑内一重要的神经内分泌器官。已发现脑脊液中存在松果体分泌物(如褪黑素Melatonin)。为探讨松果体分泌物直接释放入脑脊液通路的超微结构形态学证据。采用常规及NaOH消蚀法生物电镜样品制备技术,对成年日本猴松果体及其被囊进行了扫描和透射电镜研究。松果体囊由一层扁平上皮细胞和上皮下结缔组织构成。在面对蛛网膜下隙的囊上皮细胞和细胞间可见许多上皮孔(2～5μm);上皮下结缔组织内含成纤维细胞、胶原纤维、血管、松果体细胞突起(内含膜包密芯分泌颗粒)、有髓和无髓神经纤维等;它伸入松果体实质形成小叶间隔,分隔…     

神经垂体分泌物释放入脑脊液主要途径结构基础的电镜研究

目的探讨神经垂体分泌物直接释放入脑脊液途径的结构基础。方法透射电镜和扫描电镜观察大鼠神经垂体。结果神经垂体无髓神经纤维终止于毛细血管或垂体细胞周围,垂体细胞突起与神经纤维膨体及终末之间形成细胞间池。有孔型毛细血管内皮外有基膜与血管周隙分隔,血管周隙内可见到完整的膜包分泌颗粒(100~300 nm)。神经垂体表面的囊上皮孔(2~5μm)附近经常可见分泌颗粒。结论细胞间池-血管周隙-囊上皮孔,构成了神经垂体分泌物释放入脑脊液主渠道的结构基础。     

松果体细胞致密芯颗粒释放入细胞间小管

目的:观察松果体细胞分泌颗粒是否释放入松果体细胞间小管,以探讨松果体细胞间小管构成松果体内部特殊的管道系统并承担转运功能.方法:运用透射电镜观察12只2月龄Wistar大鼠松果体浅部.结果:Wistar大鼠松果体浅部存在细胞间小管,松果体细胞内大型致密芯颗粒非常少见.在松果体细胞内、贴近细胞间小管壁处观察到有膜包被的大型致密芯颗粒,颗粒被膜与细胞膜部分融合,形成"Ω"形状,开口于细胞间小管.结论:松果体细胞间小管是松果体内的特殊管道系统,松果体细胞分泌物可释放入细胞间小管转运.     

大鼠松果体血脑屏障的电镜细胞化学实验观察

目的：观察SD大鼠松果体血脑屏蔽的超微结构。方法：采用硝酸镧示踪电匀细胞化学结合常规电镜技术观察SD大鼠松果体毛细血管的超微结构。结果：（1）松果体毛细血管为有孔型,未见紧密连接,内皮细胞外围有周细胞,并存在较宽的,疏松的絮状基膜样物质,其中散在分布松果体细胞及神经胶质细胞的突起。（2）硝酸镧颗粒广泛分布在毛细血管腔内及其周期基膜样物质中,血管周隙处也有颗粒分布,而内皮细胞,周细胞及其突起内未见颗粒分布,结论：SD大鼠松果体缺乏血脑屏蔽结构,大分子物质容易通过毛细血管进入血管周隙。     

大鼠松果体褪黑素含量增龄性变化的研究

目的探讨大鼠松果体褪黑素含量的增龄性变化规律。方法32只健康SD大鼠随机分为1～2月龄组、4～5月龄组、11～12月龄组和≥24月龄组4个年龄组。每组8只,雌雄各半。用高效液相色谱测定松果体褪黑素含量。结果1～2月龄组褪黑素含量为1.492±0.158,4～5月龄组为1.088±0.059,11～12月龄组为0.233±0.101,≥24月龄组为0.127±0.037,各组间差异有统计学意义(P<0.01)。结论大鼠松果体随增龄而出现褪黑素含量下降,这可能是导致机体发生衰老的原因之一。     

大鼠深部松果体的神经支配和去双侧颈上节后深部松果体的变化

应用电镜观察18只正常大白鼠和8只切除双侧颈上节8周后大白鼠的深部松果体。在非手术大鼠的深部松果体中可见交感神经无髓纤维终末,它含有小颗粒泡,多位于血管周隙,也见于松果体细胞间。具有大颗粒泡的无髓神经纤维终末见于深部松果体,且与含清亮泡的神经末梢有突触性联系。深部松果体中存在大量来自缰核和后连合的有髓和无髓神经纤维。切除双侧颈上节后,大鼠深部松果体发生变化,松果体细胞核明显增大,胞浆中有不同形态空泡形成。细胞膜出现大量皱褶,细胞体积变小。交感神经终末呈清亮型溃变象。     

Aging affects choroidal proteins involved in CSF production in Sprague-Dawley rats

Aging is currently associated with progressive declines of cerebral functions. From these, a decreased resistance to dehydration suggested alteration in choroidal control of brain homeostasis and reduced cerebrospinal fluid (CSF) production in old subjects. In the present study, choroid plexuses of 20-month old Sprague-Dawley rats were compared with those of 3- and 10-month old rats. Using ultrastructure analysis and immunodetection of ezrin, a protein associating cytoskeleton to membranes, we showed that progressive loss of microvilli and strong decrease in apical ezrin are evident in 20-month old rats. Using immunolabeling and confocal microscopy, we found reduction in expression of two choroidal proteins, carbonic anhydrase II and aquaporin 1, involved in CSF secretion. In addition, we confirmed previous studies indicating that choroidal Na,K-ATPase decreased with age. In situ hybridization analyses showed that mRNA levels for Na,K-ATPase and aquaporin 1 were significantly lowered in choroid plexus of old rats. These findings are consistent with a reduced secretory activity in choroid plexus and suggest that massive disorders could affect choroidal CSF production in aged rats.     

Electron-microscopic studies on the development and aging of the oviduct epithelium of mice

Summary The fine structure of the oviduct epithelium of the newborn to the old mouse was studied with an electron microscope. Just after birth, epithelial cells lining the ampulla of the mouse oviduct are simple columnar in shape and of one type in fine structure. They contain numerous free ribosomes, an extremely poor rough endoplasmic reticulum, and a small Golgi complex. In the 3-day-old mouse, the epithelial cells are differentiated neither into ciliated nor secretory cells, and are characterized by the appearance of many autolysosomes and a solitary cilium.The ciliary cells differentiates 5 days after birth. Ciliogenesis is frequently observed at 5–10 days. The important role of the fibrous granules for ciliogenesis and that of the Golgi apparatus for membranogenesis of the cilia are described and discussed.The secretory cell having mucous secretory materials is differentiated at 23 days.In the epithelial cell lining the ampulla of the aged (22 to 24-month-old) mouse oviduct, large autolysosomes and vacuoles 2–6 m in diameter occur in the ciliated cell, though cilia and other cell organelles are well preserved. In the old mouse the secretory granules almost disappear and the rough endoplasmic reticulum is strikingly dilated in the secretory cell.No features showing the transformation between the secretory cell and the ciliary one are seen in the mouse oviduct.This paper is supported by a grant from the Japanese Eductional Ministry.     

SECRETORY GRANULES IN BENIGN AND MALIGNANT GLUCAGONOMAS OF THE PANCREAS

Two cases of glucagonoma, one benign and the other malignant, were presented. Benign glucagonoma in a 29-year old man with multiple endocrine neoplasia type 1 was composed largely of tumor cells with secretory granules ranging from 139 to 417 nm in diameter identical to A cell granules. There were a few tumor cells which contained no A cell granules but smaller granules of approximately 166 nm diameter similar to those of pancreatic polypeptide-containing cells. Radioimmunoassay of the tumor extract showed 319 μg/g wet weight of glucagon and 0.72 μg/g wet weight of pancreatic polypeptide. Malignant glucagonoma in a 34 year-old man was a massive tumor of 7x6x5 cm replacing the tail and body of the pancreas with multiple metastases. The tumor contained 0.2 μg/g wet weight of glucagon and 0.065, ug g wet weight of vasoactive intestinal peptide. The electron microscopic examination revealed that the tumor cells had variable numbers of atypical secretory granules measuring 110 to 200 nm in diameter different from A cell granules. An analysis of plasma glucagon by the gel filtration technique showed the heterogeneity of glucagon molecules indicating the presence of large glucagon. Atypical secretory granules in malignant glucagonoma were considered to represent immature granules containing the precursor or intermediate of glucagon.     

大鼠松果体衰老的形态学研究

目的 探讨松果体形态结构的衰老性变化,为进一步研究松果体与衰老的关系提供形态学基础。方法 随机选取3月龄和34月龄SD大鼠10只分别作为青年组和老年组,用光镜和电镜结合形态计量学分法分析松果体细胞和神经胶质细胞密度及其指数;松果体细胞线粒体的Vv、Sv、Nv,高尔基器的Vv、Sv、粗面内质网的Sv、溶酶体的Vv;松果体神经终末的Vv及其线粒体的Vv、Sv、Nv、小颗粒囊泡的NA。结果 与青年组相比,老年组松果体细胞核形状不规则,核膜皱褶增多和加深。细胞浆内粗面内质网减少,排列紊乱,分散,脱颗粒明显;线粒体结构不清、肿胀、嵴断裂、消失、空泡化等。老年组松果体细胞密度比青年组减少,而神经胶质细胞密度增加,差异有高度显著性(P<0.01)。老年组神经胶质细胞指数比青年组高(P<0.01)。老年线粒体Vv与青年组无差别,但老年组线粒体Sv、Nv均比青年组减少(P<0.01)。老年组高尔基器的Vv、Sv均比青年组减少(P<0.01);老年组粗面内质网Sv比青年组减少,而老年组溶酶体Vv比青年组增加(P<0.01);老年组神经终末Vv比青年组减少(P<0.01);老年组神经终末中小颗粒囊泡NA比青年组减少(P<0.01);老年组线粒体Sv、Nv比青年组减少(P<0.05),两组神经终末中线粒体Vv无差别(P>0.05)。结论 老年大鼠松果体已发生衰老性变化,这可能与机?     

外源性褪黑激素对去松果体盲鼠运动性活动昼夜节律的影响

为探讨松果体褪黑激素在哺乳动物昼夜节律调控机制中的作用，本工作对外源性褪黑激素对去松果体官大鼠运动活动昼夜节律的影响进行了实验观察。经用余弦节律分析法对实验数据进行数学分析，结果发现：无论是各只动物昼夜节律振幅的算术平值，还是用群体平均余弦法得出的群体节律的振幅，用药后都大于用药前；另外，各动物节律的峰值时相用药前较分散，即个体差异较大，而用药后相对集中，比较趋于一致据此，作者认为松果体褪黑激素对哺乳动物近昼夜节律有增大振幅和内源性步化作用。     

Aging-related reduced release of LH-releasing hormone from hypothalamic granules

The effects of aging on the secretory function of hypothalamic granules containing luteinizing hormone releasing hormone (LHRH) were examined, using chelated copper as a test substance. Granules prepared from old and young female rats were each incubated with various concentrations of CuATP and the kinetic constants of LHRH release estimated. The LHRH content of the hypothalamus of old female rats (3.4± 0.1 ng; mean±S.E.; n=3 determinations) was lower than that of young female rats (4.7±0.1 ng;n=3). CuATP-stimulated LHRH release (pg/hypothalamus) from granules isolated from old animals was significantly (p<0.001) lower than that from granules isolated from young animals; V_max being 58.5±1.6 pg (n=36) and 76.7±2.7 pg (n=34) of LHRH released/min, respectively. In contrast, the fractional amount of CuATP-stimulated of LHRH from granules isolated from old and young rats was similar; V_max being 60±0.5% and 62±1% of granule LHRH released respectively. In addition, the apparent K_m for CuATP-stimulated release of LHRH from granules of old and youn rats was also similar, 5.1 and 5.5. μM copper, respectively. These results are suggestive that aging does not alter the responsiveness of LHRH-containing granules to a secretion-stimulus such as copper but it does alter the capacity (amount) of peptide released.