Immunofluorescence study of LRH-producing neurons in prosimians (Tupaia and Galago)

Summary Reactive LRH neurons were characterized in prosimians (Tupaia and Galago) by immunofluorescence using rabbit immunesera against unconjugated synthetic LRH, or LRH conjugated with bovine serum albumin. These neurons, which vary individually in number in one species, are mainly concentrated in the rostral hypothalamus (medial preoptic area and anterior hypothalamic area) and in the lamina terminalis. In contrast to the simians and man, immunoreactive perikarya were not routinely found in the mediobasal hypothalamus of the prosimians investigated in the present study. Reactive axons of the hypothalamo-hypophyseal tract are more numerous and conspicuous in the retrochiasmatic area and in the postinfundibular eminence. They give rise to radiating collaterals ending mainly around the capillaries of the primary portal plexus of the median eminence and of the infundibular stem (where they are generally more numerous). Reactive axons of the preopticoterminal tract, originating from the perikarya of the lamina terminalis, end around the capillaries of the vascular organ or below and between the ependymal cells lining its ventricular side.In Galago a small but very distinct tract of reactive axons runs under the optic chiasma, between the lamina terminalis and the ventral labium of the infundibulum. Very fine reactive extrahypothalamic axons were observed in the posterior part of the habenular ganglia, along the preamygdaloid portion of the stria terminalis and along the blood vessels of the parolfactory area.This work was supported by a grant from the Foundation pour la Recherche Médicale Française. The author acknowledges the help of Miss D. Croix for the preparation of LRH-BSA conjugates and the radioimmunological study of the immunosera and A. Pillez (C.N.R.S.) for sectioning and staining the genital tracts     

Projections of the central cerebellar nuclei to the intralaminar thalamic nuclei in cats

Projections of the central cerebellar nuclei to the intralaminar thalamic nuclei were studied in cats with the use of light and electron microscopy. Almost all intralaminar nuclei were shown to obtain cerebello-thalamic projections. The entire complex of the central cerebellar nuclei serves as a source of such projections; yet, involvement of different nuclei is dissimilar. Destruction of the central and, especially, caudal regions of the fastigial nucleus evoked in the intralaminar thalamic nuclei degenerative changes in the nerve fibers (from swelling and development of varicosities up to total fragmentation). Pathological phenomena could be noticed in the most caudal regions of the above thalamic nuclear group, including the medial dorsal nucleus. Projections of the cerebellar interpositus nucleus were directed toward nearly the same regions of the intralaminar nuclei; degeneration was more intensive (covered thecentrum medianum) when posterior regions of the interpositus nucleus were destroyed. Destruction of the lateral cerebellar nucleus evoked a similar pattern of pathological changes, but degeneration was also observed in some structures of the ventral and anterior nuclear groups of the thalamus. Electron microscopic examination showed that degeneration of dark and light types developed in the fiber preterminals and terminals. It can be concluded that the central cerebellar nuclei project not only to the ventral complex of the thalamic nuclei, but also to the anterior, medial, and intralaminar nuclear groups (rostral and caudal portions).     

Ontogeny and morphology of the round window and aqueduct of cochlea in Tupaia and other mammals

Studied the morphogenesis of the Fenestra rotunda and of the Aquaeductus cochleae in a series of 23 dated embryos and postnatal stages of Tupaia belangeri. The ontogeny of the Fenestra rotunda is the result of the caudal growth of the Processus recessus (DE BEER 1937). The Processus arises from the caudal ridge of the floor of the cochlear part of the otic capsule. On the 28th d of ontogeny (the gestation period of Tupaia belangeri is 43 d), it is fused with the lateral edge of the parachordal plate. On the 40th d, the Processus recessus joins the ventral surface of the canalicular part of the otic capsule, which develops a small cartilaginous process to meet it. In Tupaia, the Processus recessus is a large cartilaginous plate in a nearly horizontal position. It does not reach the plane of the Foramen perilymphaticum. The Processus recessus can be regarded as a part of the parachordal plate that was shifted laterally together with the Recessus scalae tympani by the enlargement of the cochlear part of the otic capsule in the ancestors of living mammals. The Processus forms the floor of the Aquaeductus cochleae, by which the laterally shifted Recessus scalae tympani of mammals remains connected with the cranial cavity. The Aquaeductus cochleae contains the Ductus perilymphaticus connecting the Cavum perilymphaticum of the inner ear with the Cavum leptomeningeum. The Fenestra rotunda of mammals is homologous with the lateral aperture of the Recessus scalae tympani of reptiles. In some mammals (e.g. Micropotamogale), the Membrana tympani secundaria spans the lateral aperture of the Recessus scalae tympani, as in many reptiles. Both the Membrana tympani secundaria of reptiles and that of mammals are homologous. Secondarily, in a large number of therian mammals (e.g. Myotis [Frick 1952]), the tympanic cavity extends into the Recessus scalae tympani displacing the Membrana tympani secundaria medially from the lateral aperture of the Recessus scalae tympani (= Fenestra rotunda of mammals) and even into the plane of the Foramen perilymphaticum. Thereby the Fossula fenestrae rotundae is formed, which in bounded medially by the Membrana tympani secundaria.     

小脑间位核对淋巴细胞功能的调节作用

目的:研究小脑深部核团之一间位核对淋巴细胞功能的调节作用,以拓宽对小脑功能的认识进而增加神经免疫学的知识.方法:在大鼠双侧小脑间位核内注射海人酸(KA)以损毁间位核内神经元的胞体,并设对照组,于小脑间位核内注入等量生理盐水.在手术后的第8、16、32 d分别用血细胞计数法检测动物外周血中淋巴细胞的数量;用四甲基偶氮唑(MTT)比色法检测动物肠系膜淋巴结细胞对刀豆蛋白A(Con A)刺激的增殖反应;用ELISA法检测动物血清中抗绵羊红细胞(SRBC)特异性IgM抗体的生成能力;用流式细胞术测定脾脏自然杀伤(NK)细胞的活性.结果:小脑间位核损毁后的第8、16、32 d,动物外周血中淋巴细胞数都明显低于损毁手术前的淋巴细胞数,也显著低于生理盐水对照组相应时间段的淋巴细胞数.在小脑间位核注射KA后的第8、16、32 d,动物的肠系膜淋巴结细胞由Con A诱导的增殖反应、血清中特异性抗SRBC IgM抗体的生成能力和脾脏NK细胞杀伤靶细胞YAC-1的活性均明显低于生理盐水对照组,但比较损毁后不同时间段的T、B和NK细胞功能的变化,没有发现显著的差异.结论:小脑双侧间位核损毁可导致总淋巴细胞数以及T、B和NK细胞功能均发生不可逆的降低,充分说明小脑间位核可调节淋巴细胞的功能,并提示在正常体内,小脑间位核对淋巴细胞功能具有增强效应.     

Development of human cerebellar nuclei. Morphometric study

The morphometric development of the human cerebellar nuclei was examined in 9 fetuses (16-40 weeks of gestation; WG), an infant (2 months old) and 2 adults (16 and 63 years old). With the morphological observation of serial sections of the brain containing the cerebellar nuclei, the authors measured sections to get several morphometric parameters: the volume of nuclear column and number, packing density and cell body area of neurons. Each nucleus (dentate, emboliform, globose and fastigial nucleus) was recognized even at 16 WG. Nerve cells containing Nissl bodies were observed in all nuclei after 23 WG. Degenerative changes were detected in some neurons for every nucleus at 21 and 23 WG. Three stages were observed in the developmental course of nuclear volume and neuronal packing density: the primary or undifferentiated stage at 16 WG, the secondary stage with variability at 21-32 WG and the tertiary stage with monotonous increase (nuclear volume) or gradual decrease (neuronal packing density) after 35 WG. No significant correlation between neuronal number and gestational age was noticed for every nucleus. The analysis of cell body area (neuronal size) demonstrated that the dentate neurons developed after the intermediate or fastigial neurons. It is concluded that there is a critical period between slightly before 20 WG and slightly after 30 WG, matched with the secondary stage in the development of the cerebellar nuclei.