三角鲂( Megalobrama terminalis) 脑垂体的超微结构

研究三角鲂(Megalobrama terminalis）脑垂体的超微结构，脑垂体由神经垂体和腺垂体构成，神经垂体组织中存在A1、A2和B型神经分泌纤维和一种脑垂体细胞，腺垂体由促肾上腺皮质激素分泌细胞(ACTH)、催乳激素分泌细胞(PRL)、生长激素分泌细胞(GH)、促甲状腺激素分泌细胞(TSH)、促性腺激素分泌细胞(GTH)、促黑色素分泌细胞(MSH)、PAS-反应细胞和一种非分泌类型的星状细胞(SC)构成，并讨论三角鲂神经垂体和腺垂体的结构特点。     

赤点石斑鱼脑垂体超微结构的初步研究

 应用透射电镜技术观察不同时期的性成熟赤点石斑鱼（Epinephelus akaara）脑垂体的超微结构。结果表明,性成熟赤点石斑鱼脑垂体近椭圆形,由神经垂体和腺垂体两部分组成。神经垂体主要由神经纤维、脑垂体细胞和微血管组成。其中神经分泌纤维存在A(A1、A2)和B型神经分泌纤维。腺垂体中外侧部（PPD）腺细胞由嗜酸性的GH细胞和嗜碱性的TSH细胞及GTH细胞3类细胞构成。在不同的时期,GTH细胞内的分泌颗粒明显不同。     

鲇脑垂体发生形态学的光镜和激光扫描共聚焦显微观察

应用光镜和激光扫描共聚焦显微镜时鲇脑垂体发生形态学进行观察：鲇脑垂体由两个不同部位的胚胎细胞形成,原始口腔背壁外呸层分离出来的细胞构成腺垂体的前外侧部(RPD)和中外侧部(PPD),从间脑腹面漏斗体分离出来的细胞卡构成腺垂体中间部(PI)及神经垂体．3d龄仔鱼脑垂体的形态业已建成,属前后型．5d龄仔鱼脑垂体可区分出神经垂体及腺垂体,腺垂体可区分出RPD、PPD、和PI3个区域,并开始出现毛细血管．此时,PPD内的生长激素(GH)细胞已经分化．11d龄稚鱼脑垂体中除PPD内GH细胞已分化外,未见其它促激素分泌细胞分化．15d龄稚鱼脑垂体PPD内的促肾上腺皮质素(ACTH)细胞及催乳激素(PRL)细胞已分化．20d龄稚鱼脑垂体内各种激素分泌细胞完全分化．11d龄以前仔鱼脑垂体属前后型,15d龄和20d龄的稚鱼脑垂体内RPD、PPD和P13部分呈直状排列．性成熟鲇脑垂体结构旱背腹型．     

瓦氏黄颡鱼脑垂体组织学和组织化学研究

对不同季节瓦氏黄颡鱼成鱼脑垂体进行组织学和组织化学研究.结果表明:瓦氏黄颡鱼脑垂体为背腹型腺体.神经垂体居中,前腺垂体位于垂体背面前部和后缘,由PRL细胞和ACTH细胞组成;中腺垂体位于垂体中部及背面后部,包括GH细胞、GTH细胞和TSH细胞,后腺垂体位于垂体腹面后方,组织学研究仅见一种分泌细胞.前腺垂体ACTH细胞形态、中腺垂体GTH细胞形态和数量在繁殖前后有明显变化,与生殖活动密切相关.     

初孵扬子鳄脑垂体P物质的免疫组织化学研究

用免疫组织化学方法观察了P物质在初孵扬子鳄脑垂体的分布特点.P物质阳性细胞分布于初孵扬子鳄脑垂体内侧腺垂体部,阳性纤维分布于初孵扬子鳄脑垂体外侧的神经部.结果表明P物质可能对垂体内分泌细胞有调节作用.     

中国对虾眼柄的神经分泌结构

研究了中国对虾眼柄神经分泌结构特征。眼柄神经分泌结构由神经分泌细胞和窦腺两部分组成。依据细胞及其核直径和细胞质特征等将神经分泌细胞分为６种类型,它们多以集群方式分布,少数则分布较为分散。窦腺位于眼柄视神经节内髓外侧,呈椭圆囊状。依据神经分泌细胞轴突末梢直径和其内颗粒特征将窦腺内轴突末梢分为４种类型。     

南方鲇成鱼垂体的组织学与组织化学

运用组织学、组织化学技术对南方鲇成鱼垂体结构在生殖周期中的变化进行了研究.结果表明:南方鲇垂体为背腹型腺体,由神经垂体和腺垂体组成,神经垂体位于腺垂体中央;腺垂体前外侧部位于腺体前部,由PRL、ACTH细胞和少量GH、GTH细胞组成;中外侧部位于腺体中部及后部腹面区域,由GH、GTH和TSH细胞组成;中间部位于腺体后部背面,包括MSH、GTH细胞和首次在鱼类报道的大型泡状细胞.GTH和ACTH细胞结构在生殖周期中发生明显的变化,与生殖活动密切相关.     

鲤鱼神经垂体的超微结构研究

经电子显微镜观察，提出鲤鱼神经垂体由有髓神经分泌纤维和三种无髓神经分泌纤维以及垂体细胞和毛细血管组成，神经分泌纤维与垂体细胞之间存在着突触联系，神经分泌纤维之间只有细胞间连接。在神经垂体组织中还存在Ⅰ型和Ⅱ型两种结构与功能不同的垂体细胞，另外在血管间道内观察到了很少见的特殊空泡结构。     

尼罗罗非鱼腺垂体的显微和超微结构研究

对尼罗罗非鱼(Tilapia nilotica)的腺垂体进行显微和超微结构研究.通过Heidenhain-Azen和PFA-AB-PAS-OG染色,比较腺垂体的腺细胞类型及在腺垂体前叶、间叶和过渡叶的分布.在电镜水平上对腺垂体七类内分泌细胞的超微结构和对前叶存在的一种非分泌细胞(星状细胞)作描述和讨论.结果表明,同属罗非鱼内分泌腺细胞在腺垂体的分布和染色特征是相一致的.     

卵巢发育过程拟穴青蟹前脑神经分泌细胞超微结构的变化

利用透射电镜,比较观察了拟穴青蟹(Scylla paramamosain)卵巢未发育期、将成熟期和成熟期前脑神经分泌细胞的超微结构.结果表明:在未发育期,前脑神经细胞尚未观察到神经分泌颗粒.在将成熟期.前脑Ⅱ型、Ⅲ型细胞均出现大量的神经分泌颗粒.在成熟期,Ⅱ型、Ⅲ型细胞神经分泌颗粒大量释放.拟穴青蟹卵巢成熟发育过程前脑Ⅱ型、Ⅲ型细胞超微结构的变化,提示Ⅱ型、Ⅲ型细胞可能是促性腺激素细胞,参与生殖内分泌调控.     

Relaxin affects the release of oxytocin and vasopressin from the neurohypophysis

The hormone relaxin has recently been shown to inhibit not only uterine muscle contraction, but also the release of oxytocin into the plasma. Intravenous injection of porcine relaxin in anaesthetized lactating rats inhibits milk ejection and injection of relaxin into the cerebral ventricles disturbs the pattern of the milk ejection reflex. Recent experiments performed in vivo indicate that relaxin might act not only in the uterus, but also in the hypothalamus and possibly in the neurohypophysis. We tested this hypothesis in vitro by studying the effect of relaxin on hormone release from isolated neural lobes of the pituitary and isolated neurosecretory nerve endings of the neurohypophysis from the rat. We report here that relaxin has a dual effect on neurohypophysial hormone secretion. Under basal conditions, vasopressin and oxytocin release was inhibited by relaxin but, when the nerve endings were depolarized, vasopressin and oxytocin secretion was potentiated. We also found that relaxin acts at a stage before the increase in cytoplasmic free Ca2+ that is necessary for inducing hormone release, possibly by gating the calcium channel.     

Magnocellular axons in passage through the median eminence release vasopressin

Vasopressin (arginine vasopressin, AVP) is present in two types of nerve fibres in the median eminence (ME). First, it is found in nerve terminals that originate in the parvicellular neurones of the hypothalamic paraventricular nucleus (PVN) and abut on the pericapillary space surrounding the fenestrated capillaries of the primary pituitary portal plexus in the external zone (EZ) of the ME. These neurones also synthesize corticotropin-releasing factor (CRF), which acts synergetically with vasopressin to stimulate release of adrenocorticotropin (ACTH) from the pituitary gland (see ref. 7). Second, vasopressinergic axons of the magnocellular neurosecretory system pass through the internal zone (IZ) of the ME to terminate in the neurohaemal contact zone of the neurohypophysis. The involvement of vasopressinergic magnocellular neurones in the control of ACTH secretion is much debated. Of particular interest in this context is the origin of the vasopressin found in pituitary portal blood. Although it has been demonstrated that vasopressin and CRF are present in the same neurosecretory granules of EZ fibres, parallel determinations of vasopressin and CRF in pituitary portal blood have shown alterations of the concentration of vasopressin without a concomitant change in that of CRF. Such a dissociation suggests that either differential release of vasopressin and CRF can occur from a single population of nerve endings, or there are fibres in the pituitary-stalk ME which release vasopressin but not CRF. Here we present evidence for the latter. Our results indicate that stimuli causing depolarization of the axonal membrane in vitro elicit release of vasopressin from nerve fibres in the external and internal zones of the ME.     

Evidence for opiate receptors on pituicytes

A hypothalamo-neurohypophyseal enkephalinergic pathway has been described and the pars nervosa of the rat pituitary contains enkephalin-like material which may coexist in vasopressin and oxytocin terminals. At the level of the pars nervosa itself, stereospecific opiate receptors with properties very similar to those of brain receptors have been described, and opiates have been shown to inhibit the release of both vasopressin and oxytocin. The location of the opiate receptors involved has been presumed to be pre-terminal on the neurosecretory fibres. Using an autoradiographic technique to visualize opiate receptors, however, we now report that destruction of the neurosecretory fibres following pituitary stalk section does not result in a significant change in the neural lobe opiate receptor population. This suggests that the opiate receptors within the neural lobe may be present on pituicytes rather than on neurosecretory fibres.     

威廉环毛蚓Pheretima guillelmi(Michaelsen)神经内分泌系统的研究

以威廉环毛蚓为实验材料,对其神经内分泌系统的显微、亚显微结构及其对体表水交换的影响作了初步研究.通过大量的实验,说明在威廉环毛蚓的中枢神经系统中存在三种不同类型的细胞,即A、B和C三种细胞.A细胞数量最多,位于脑神经节、咽下神经节和腹神经索中.B细胞主要位于咽下神经节.C细胞主要位于咽下神经节和腹神经索中.神经内分泌活动与季节有关,A细胞和C细胞的分泌活动随季节变化而不同,B细胞的内分泌活动受季节的影响不大.蚯蚓体表的水交换受神经内分泌调控,这种因子仅存在于脑神经节内.     

法国鹌鹑脑垂体神经叶的超微结构研究

用电子显微镜技术,对法国鹌鹑脑垂体神经叶的超微结构进行了研究,观察结果表明,脑垂体神经叶由无髓神经纤维及末梢、垂体细胞,室管膜细胞、毛细血管、结缔组织构成,无髓神经纤维末梢内含许多神经分泌颗粒,大多终止于有孔型毛细血管的基膜外,这为分泌物质放入血提供了有利条件,神经叶中漏斗隐有面有一层室管膜细胞,室管膜细胞基部与神经末梢紧密相接,此外胞质中可见微吞饮小泡,因此认为,室管膜细胞可能参与社会分泌物质的释放。     

Capacitance steps and fusion pores of small and large-dense-core vesicles in nerve terminals

The vesicles that package neurotransmitters fall into two distinct classes, large dense-core vesicles (LDCVs) and small synaptic vesicles, the coexistence of which is widespread in nerve terminals. High resolution capacitance recording reveals unitary steps proportional to vesicle size. Measurements of capacitance steps during LDCV and secretory granule fusion in endocrine and immune cells have provided important insights into exocytosis; however, extending these measurements to small synaptic vesicles has proven difficult. Here we report single vesicle capacitance steps in posterior pituitary nerve terminals. These nerve terminals contain neuropeptide-laden LDCVs, as well as microvesicles. Microvesicles are similar to synaptic vesicles in size, morphology and molecular composition, but their contents are unknown. Capacitance steps of two characteristic sizes, corresponding with microvesicles and LDCVs, were detected in patches of nerve terminal membrane. Both types of vesicles fuse in response to depolarization-induced Ca(2+) entry. Both undergo a reversible fusion process commonly referred to as 'kiss-and-run', but only rarely. Fusion pores seen during microvesicle kiss-and-run have a conductance of 19 pS, 11 times smaller than LDCV fusion pores. Thus, LDCVs and microvesicles use structurally different intermediates during exocytosis.