大鼠松果体的神经支配--免疫组织化学及光镜体视学研究

目的探讨大鼠松果体的神经支配及双侧颈上交感神经节摘除后对松果体细胞分泌活动的影响。方法免疫组织化学、光学体视框及图像分析方法。结果松果体内神经末梢、松果体细胞及其突起终末呈突触体素(P38)免疫组织化学阳性反应。摘除了双侧颈上交感神经节后,大鼠松果体所含神经末梢的平均数密度减少了43%(P<0.01),平均每个大鼠松果体内所含神经末梢总数减少了37%(P<0.05),松果体细胞及其突起终末内突触体素免疫阳性产物的平均A值明显降低(P<0.01)。结论支配松果体的神经纤维有很大部分来自双侧颈上交感神经节,这些神经纤维对松果体细胞的分泌功能产生明显影响。     

松果体的神经支配

电镜观察松果体实质,证明充满联合神经分支的薄层有神经纤维,这些纤维与明、暗细胞及神经胶质细胞的胞体和突起紧密相贴。接触点,胞膜增厚,髓鞘内主致密线消失,周期间线空隙加宽,出现施兰氏切迹样结构。无髓交感神经纤维终末膨大,含致密中心小泡,多分布于松果体细胞旁及血管周。本文阐明松果体系由联合神经及交感神经双重支配。     

松果体内的神经纤维终末同松果体细胞的联系—电镜定量研究

目的研究松果体内神经纤维终末同松果体细胞间的联系方式.方法取12只成年雄性SD大鼠浅松果体,作常规电镜包埋,电镜下等距随机选点观察拍照并作形态定量测试.结果(1)松果体细胞体积约占松果体体积的75.9%±3.8(X±S-x),松果体细胞间隙和血管周围间隙体积占整个松果体体积的22.0%±3.5;在血管周围间隙中松果体细胞游离面表面积占松果体细胞整个界面面积的46%;(2)松果体细胞的球状突起轮廓数共计数155个,其中101个游离在血管周围间隙内;(3)共计数各种类型的神经纤维终末轮廓数248个,其中221个游离在血管周围间隙内,23个与松果体细胞胞体相贴,1个与细胞突起相贴,3个与松果体细胞形成突触.结论提示进入松果体的交感神经纤维终末对松果体细胞活动的调控主要是通过神经体液途径.     

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?     

荧光金顺行追踪结合免疫荧光组化法在大鼠松果体神经供给研究中的应用

哺乳类动物的松果体 ( Pineal body)是一个重要的神经内分泌器官 ,具有多种生理功能 ,这些功能与其神经供给有着密切的关系。以往的许多研究曾通过摘除双侧颈上交感神经节 ,逆行追踪等手段来证明松果体主要接受颈上交感神经节的节后神经纤维支配 ,但尚未见将示踪剂直接注入双侧颈上交感神经节以了解颈上交感神经节内直接投射到松果体的神经纤维数量、分布及性质的详细报道。为此 ,我们将荧光金 ( fluoro- gold,FG)顺行追踪结合免疫荧光组化法应用于松果体神经供给的研究之中。1　材料和方法1 .1　动物选择 :成年健康雄性 SD大鼠 (华西医大…     

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.     

大鼠松果体的中枢神经支配──病毒跨神经元顺行追踪研究

大量研究证明，松果体（Pi）的功能同它的神经支配密切相关，因此，研究Pi的神经支配就十分必要。但长期以来对此存在着异议，一些学者认为Pi的神经支配仅来源于双侧颈上交感神经节（SCG），另一些又提出Pi的神经支配不仅来源于SCG，而且也接受来自脑或其它地方的纤维投射。本研究用假狂犬病毒（PRV）作顺行跨神经元追踪，进一步探讨Pi的神经支配。17只雄性SD大鼠在单侧眼球内注入3一PRV（Bartha株、5X10’PFU／ml）前施行双侧SCG摘除术，术后分别存活56、72和96hr。PRV标记的神经元用免疫组化ABC法显示。结果；（1）56hr组仅在视交叉上核（SCN）内在极少数神经元被PRV标记；（2）72hr组除SCN外，在丘脑下部前区、下丘脑室旁核（PVN）、缰核（Hb）和外侧膝状体（LGH）出现了PRV标记的神经元。与此同时，在松果体的被膜内和松果体细胞之间也呈现出PRV标记的神经纤维；（3）随着动物存活时！和延长，96hr组在上述提及区域内被PRV标记的神经元和神经纤维数量增多。以上结果表明松果体接受了来自视网膜节细胞（RGC）的光信息。结合其他学者的报道，我们推测从视网膜及下丘脑投射到松果体的神经通路可能有以下几条：①RGC～LGH～Pi。＠PGC～Hb～Pi，＠SCN～PVN—Pi，＠SCN～LGH～Pi和⑤SCN～Hb－Pi。不论从哪     

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。     

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…     

Expression of protein gene product 9.5, tyrosine hydroxylase and serotonin in the pineal gland of rats with streptozotocin-induced diabetes

Hyperglycemia is a well-known factor in reducing nocturnal pineal melatonin production. However, the mechanism underlying diabetes-induced insufficiency of pineal melatonin has remained uncertain. This study was undertaken to examine the structure, innervation and functional activity of the pineal gland in streptozotocin (STZ)-induced diabetes in rats by immunohistochemistry, Western blotting and image analysis. The number of the pinealocytes and the volume of pineal were also estimated using stereologic quantification including the optical fractionator and Cavalieri's method. It has also shown a progressive reduction of the total area of the pineal gland and the nuclear size of pinealocytes beginning at 4 weeks of induced diabetes. Surprisingly, the immunoreactive intensities and protein amounts of serotonin (5-HT) and protein gene product (PGP) 9.5 in the pineal gland were progressively increased from 4 weeks of diabetes. Meanwhile, nerve fibers immunoreactive for PGP 9.5 had disappeared. Diabetes-induced neuropathy was observed in nerve fibers containing tyrosine hydroxylase (TH). The affected nerve fibers appeared swollen and smooth in outline but they showed a distribution pattern, packing density and protein levels comparable to those of the age-matched control animals. Ultrastructural observations have revealed diabetes-induced deformity of Schwann cells and basal lamina, accumulation of synaptic vesicles and deprivation of the dense-core vesicles in the axon terminals and varicosities. The increase in immunoreactivities in 5-HT and PGP 9.5 and shrinkage of pineal gland in the diabetic rats suggest an inefficient enzyme activity of the pinealocytes. This coupled with the occurrence of anomalous TH nerve fibers, may lead to an ineffective sympathetic innervation of the pinealocytes resulting in reduced melatonin production in STZ-induced diabetes.     

Synaptic junctions between sympathetic axon terminals and pinealocytes in the monkey Macaca fascicularis

Summary The distribution of axon terminals in the pineal gland of monkeys was studied by electron microscopy. Numerous terminals bearing small pleomorphic agranular and dense-cored vesicles were localized in the perivascular space and among the pinealocytes in the parenchyma in normal monkeys. Following bilateral superior cervical ganglionectomy, they underwent degenerative changes, including the accumulation of glycogen masses, appearance of dense residual bodies and the displacement of synaptic vesicles. Some of these degenerating terminals showed synaptic contacts with the cell bodies of pinealocytes. At the synaptic junction the postsynaptic membrane was thickened asymmetrically. Examples of synaptic contacts were most frequently observed in 5 and 7 days postoperative animals. In the longer surviving (30 days) monkey, most of the axon terminals showed round agranular vesicles, and they were mainly presynaptic to the intrapineal ganglion cells with some of the pinealocytes. They remained structurally unchanged following the resection of both the superior cervical ganglia. A few axon terminals containing small dense-cored vesicles appeared to have survived the initial insult, but some of their vesicles appeared swollen 30 days after the operation. It is concluded from this study that some of the pinealocytes are under the influence by the postganglionic neurons in the superior cervical ganglia through direct synaptic contacts. The intrapineal ganglion cells are postsynaptic to fibres originating exclusively from the central nervous system. Some of these fibres, however, may be presynaptic directly to pinealocytes.     

Effects of central and peripheral inputs on single pineal cell activity in the rat

The influences exerted by central and peripheral afferents to the pineal gland have been studied in rats anesthetized with urethane (1.2 g/kg, i.p.). Spontaneous action potentials arising from the pinealocytes were recorded by means of glass micropipettes filled with 3 M NaCl containing a dye. The electrical stimulation of suprachiasmatic nucleus, superior cervical ganglia, sciatic nerve and retina evoked discharge changes in a significant number of pineal cells. However, a relatively higher proportion of pinealocytes failed to respond to these afferents. Three types of responses could be observed. Inhibitions were the predominant response patterns to suprachiasmatic nucleus, superior cervical ganglia and sciatic nerve, while excitations were mainly elicited following photic stimulation, whereas the remaining evoked activity was biphasic responses, which were observed in a small number of cells after stimulation of suprachiasmatic nucleus, superior cervical ganglia and retina. These data confirm some previous neural inputs to the pineal and demonstrate the existence of a modulatory effect of the suprachiasmatic nucleus on pinealocyte discharges as well as somatosensory afferents to the gland by way of the sciatic nerve.     

Non-sympathetic synaptic innervation of the pinealocyte of the Mongolian gerbil (Meriones unguiculatus): an electron microscopic study

Summary Direct synaptic innervation of pinealocytes was observed in the superficial pineal gland of the Mongolian gerbil (Meriones unguiculatus) by electron microscopy. This innervation consisted of nerve fibres terminating in boutons with clear transmitter vesicles with a diameter of 40–60 nm. The boutons made synaptic junctions with the cell membrane of the pinealocyte displaying thickenings of both the pre- and postsynaptic membranes. Such boutons persisted in the gland 1 week after removal of both superior cervical ganglia. In contrast, all the sympathetic boutons containing transmitter vesicles with a small dense core disappeared after ganglionectomy. This direct synaptic innervation reveals a neuronal character of the pinealocyte and might underlie reports of action potentials in electrophysiological recordings from the gland.     

Ultrastructural study of the human pineal gland in aged patients including a centenarian

An ultrastructural study of human pineal glands obtained at autopsy from 7 patients older than 70 years was conducted in order to clarify the functional anatomy of the pineal in the aged. By light microscopy, the pineal glands from aged patients were parenchymatous and almost indistinguishable from those of younger controls. Electron microscopy of the pineal parenchymal cells revealed deep nuclear indentations, synaptic ribbons and ribbon fields, Golgi apparatus, lipofuscin granules and microtubular sheaves in all subjects, cilia with a 9 + 0 pattern in a few, and lamellated structures suggestive of the outer segment of photoreceptor cells very rarely. Microtubules were numerous in the cytoplasmic processes and bulbous endings. Fibrous astrocytes located between the pinealocytes showed long and thin cytoplasmic processes containing numerous glial filaments. Two types of nerve bouton were present in the pineal parenchyma, one of which contained clear vesicles forming synapse-like contacts with pinealocytes. There were no significant age-related changes in these features in a qualitative comparison with pineal glands from 5 adult patients younger than 70 years. These findings indicate that even in advanced age, the human pineal gland maintains some functions, such as intercellular communication and photoreception, in common with the pineal in lower vertebrates.     

Ultra structural Study of the Human Pineal Gland in Aged Patients Including a Centenarian

An ultrastructural study of human pineal glands obtained at autopsy from 7 patients older than 70 years was conducted in order to clarify the functional anatomy of the pineal in the aged. By light microscopy, the pineal glands from aged patients were parenchymatous and almost indistinguishable from those of younger controls. Electron microscopy of the pineal parenchymal cells revealed deep nuclear indentations, synaptic ribbons and ribbon fields, Golgi apparatus, lipofuscin granules and microtubular sheaves in all subjects, cilia with a 9+0 pattern in a few, and lamellated structures suggestive of the outer segment of photoreceptor cells very rarely. Microtubules were numerous in the cytoplasmic processes and bulbous endings. Fibrous astrocytes located between the pinealocytes showed long and thin cytoplasmic processes containing numerous glial filaments. Two types of nerve bouton were present in the pineal parenchyma, one of which contained clear vesicles forming synapse like contacts with pinealocytes. There were no significant age-related changes in these features in a qualitative comparison with pineal glands from 5 adult patients younger than 70 years. These findings indicate that even in advanced age, the human pineal gland maintains some functions, such as intercellular communication and photoreception, in common with the pineal in lower vertebrates. Acta Pathol Jpn 40: 30–40, 1990.     

Ultrastructure of the pineal gland of the fox

The ultrastructure of the pineal gland of the fox was examined and compared with that of other mammals. The pineal gland of the fox is composed of two different populations of pinealocytes (I and II). The pinealocytes I were distributed homogeneously throughout the parenchyma, while pinealocytes II were located generally near blood vessels. A Golgi apparatus, granular endo-plasmic reticulum, mitochondria, lysosomes, centrioles, and cilia were present in both cell populations. A characteristic feature of pinealocytes I was the presence of dense-core vesicles, presumably of Golgi origin; whereas glycogen deposits and pigment granules were common features of pinealocytes II. In addition to the pinealocytes, the parenchyma contained fibrous astrocytes. The capillaries of the pineal gland of the fox consisted of a nonfenestrated endothelium. Numerous nerve fibers, presumably adrenergic, were observed throughout the parenchyma.     

Ultrastructure of the pineal body of the common vampire bat,Desmodus rotundus

The type AB pineal body of the common vampire bat, Desmodus rotundus was recessed and lobulated, was extensively vascularized and intimately related to great veins, and was unassociated with the epithalamic region. The habenular and the posterior commmissures coursed anteriorly and were unassociated with the pineal. The saccular suprapineal recess of the third ventricle extended dorsally juxtaposed to the pineal body. These anatomical features are likely to make pinealectomies in the vampire more difficult to manage. The pineal parenchyma consisted of light pinealocytes surrounded by canaliculi of various sizes, often transmitting unmyelinated nerve fibers and glial processes. Desmosomes were common. The pinealocyte nuclei were large and highly infolded; characteristic cytoplasmic constituents included abundant dilated Golgi complexes associated with clear vesicles, numerous polyribosomes, few single cisternae of ribosome-studded rough endoplasmic reticulum, mitochondria, and occasional multivesicular bodies and lysosomes. Almost all pinealocytes exhibited centrioles and some, in addition, displayed basal bodies but rarely ciliary shafts. A conspicuous feature of the pinealocyte cytoplasm was the presence of branched bundles of intermediate filaments, especially in the perinuclear zone. Siderotic macrophages, lipofuscin-pigment-containing phagocytic cells, mast cells, myelin bodies, and both fenestrated and continuous capillaries were present. The perivascular compartment was densely packed with unmyelinated nerve bundles containing small to large fibers exhibiting axoaxonic densities. Other constituents of the perivascular compartment were club-shaped pinealocyte processes filled with clear vesicles, microtubules, an occasional mitochondrion, glial processes, and collagen fibers. “Synapselike” contacts were observed between the axons and pinealocyte processes. Abundant pinocytotic vesicles in the capillary endothelium indicated active pinocytosis. Myelinated nerve fibers were lacking. The pineal ultrastructure of Desmodus is in part unlike that reported for other mammals, including bats.     

Junctional systems in the pineal gland of the Wistar rat (Ratus ratus). A freeze-fracture and thin section study

Intercellular junctions between neighbouring pinealocytes, glial cells, glial cells and pinealocytes as well as between nerve endings and parenchymal cells of the pineal gland of Wistar rats were investigated on freeze-fracture replicas and thin sections by transmission electron microscopy. Gap junctions, tight junctions and the annular gap junctions have been revealed. In addition, chemical synapses between nerve endings and pinealocytes have been observed.