摘要:

AbstractSulfated glycosaminoglycans deposition during rat postnatal cerebellar developmental is affected by altered thyroid states and undernutrition. These ontogenetic alterations seem not to be specific but to be one aspect of the general acceleration, slowing down and reduction of the cerebellar development occurring in thyroid‐deficient, hyperthyroid and undernourished rats, respectively.

ISSN:0736-5748    

DOI:10.1016/0736-5748(89)90053-1

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractThe early postnatal pattern of hyaluronic acid (HA) deposition in rat cerebellum is affected by thyroid deficiency, thyroxine treatment and undernutrition. The modification of HA ontogenesis apparently reflects the smaller number of cells formed in undernourished rats, or alterations of cell maturation (accelerated in thyroxine‐treated and slowed down in thyroid‐deficient rats). The developmentally regulated:loss of tissue water is also affected in the three conditions; this can be correlated with the roughly simultaneous disappearance of extracellular, but not of total, HA.

ISSN:0736-5748    

DOI:10.1016/0736-5748(89)90054-3

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractAlteration of rat postnatal cerebellar development produced by undernutrition, thyroxine treatment and thyroid deficiency also involves ganglioside deposition. The distribution of the different ganglioside types is apparently unaffected but quantitative alterations are present that reflect the reduction of cell number and cell process surface in the adult, and either acceleration or slowing down or reduction of cell formation and maturation occurring during cerebellar development in the three experimental situations.

ISSN:0736-5748    

DOI:10.1016/0736-5748(89)90055-5

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractPrimary dissociated cultures derived from 15‐day‐old rat embryo spinal cord with or without dorsal root ganglia (DRG) were grown on polylysine, Primaria®and laminin substrates. On polylysine and Primaria substrates, spinal cord neurons formed aggregates connected by bundles of neurites in a distinctive pattern similar to that observed in cultures derived from embryonal rat brain and neonatal rat cerebellum. After 2 days in culture, the number of cells stained with GFAP antibodies progressively increased within the vimentin‐positive monolayer surrounding the neuronal aggregates. These astrocytes had the typical appearance of astrocytes in primary dissociated cultures derived from late fetal or early neonatal murine brain, i.e. large flat or stellate cells with thick processes staining equally well with GFAP and vimentin antibodies. Astrocytes found within the neuronal aggregates in 4–5 day cultures were markedly different, i.e. small stellate cells with slender processes forming a delicate mesh throughout the aggregate. These GFAP‐positive cells stained only weakly with vimentin antibodies. Spinal cord neurons formed aggregates on laminin substrates but failed to extend neurites and rapidly degenerated. The large flat cells in the surrounding monolayer gradually invaded the aggregates. These cells stained with both GFAP and vimentin antibodies. DRG neurons developed equally well on Primaria and laminin substrates, extending their neurites on the vimentin‐positive flat cells forming the monolayer regardless of their reactivity with GFAP antibodies.

ISSN:0736-5748    

DOI:10.1016/0736-5748(89)90056-7

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractIn the rat hypothalamus, neuropeptide Y‐containing neurons first appeared on day 14.5 of gestation in the arcuate nucleus and in the dorsolateral hypothalamic area. Until birth neuropeptide Y‐containing cell bodies increased in number in the arcuate, dorsomedial‐lateral and paraventricular nuclei, but disappeared thereafter, but some cells remaining in the arcuate nucleus. In animals treated neonatally with monosodiuml‐glutamate to destroy the arcuate nucleus, neuropeptide Y‐immunoreactivity became evident in many cells scattered in the magnocellular paraventricular and dorsomediallateral hypothalamic nuclei on day 16 but not on days 60 and 120. These neuropeptide Y‐immunoreactive neurons which appeared in the paraventricular nucleus were also vasopressin‐positive. Neuropeptide Y fibers, on the contrary, remarkably diminished in number on day 16, particularly in the paraventricular and dorsomedial‐lateral nuclei, and the medial preoptic area, but made a considerable recovery on days 60 and 120. Hence it is probable that, in normal ontogenetic progress, the development of the neuropeptide Y fibers in these areas is inhibitorily affected by that of arcuate neuropeptide Y neurons.

ISSN:0736-5748    

DOI:10.1016/0736-5748(89)90057-9

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractRetinal growth from expiants attached to different substrates was evaluated in the absence and the presence of various concentrations of taurine. Fiber thickness was higher in poly‐l‐lysine, collagen and laminin than in the other substrates tested. Explants on wheatgerm, soybean, and red kidney bean lectins did not show emission of neuntes at 5 days in culture; growth on laminin was very poor at this period of time. By day 10 nerve growth index was possible to evaluate on soybean and laminin. Outgrowth from retinal explants on wheatgerm lectin was only observed in the presence of taurine. The percentage of growing explants on laminin was increased by the amino acid. Emission of neurites from explants on concanavalin A and lentil lectin was constant from 5 to 10 days in culture and was not accelerated or increased by taurine. Growth on poly‐l‐lysine and collagen was stimulated by the addition of taurine in a concentration‐dependent manner. The amino acid stimulates outgrowth from expiants attached to peanut lectin in a bell‐shaped concentration dependency similar to that observed on poly‐l‐lysine. The effect of taurine on retinal expiants is substrate‐dependent, as an indication of the interaction of soluble molecular components plus charge and structure of the extracellular matrix in order to modulate the outgrowth from regenerating tissue.

ISSN:0736-5748    

DOI:10.1016/0736-5748(89)90058-0

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractCholine acetyltransferase (ChAT) activity in developing spinal cord explantsin vitrois shown to be dependent on the presence of co‐cultured immature limb tissue. Frog tadpole spinal cord explants grown on collagen or polylysine expressed stage‐appropriate levels of ChAT activity only when in the presence of the limb mesenchyme target. Neither skeletal muscle nor polylysine, both of which enhance neurite growth accompanied by increases in cord protein, were capable of maintaining the level of ChAT activity characteristic of these spinal cordsin vivo. The results demonstrate that developmentally significant levels of ChAT can be maintainedin vitrounder appropriate conditions that may act in part through the maintenance of cholinergic motor neurons.

ISSN:0736-5748    

DOI:10.1016/0736-5748(89)90059-2

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractThe neuritic growth patterns obtained on substrates made of several glycosaminoglycans (GAGs) bound to type I collagen were analysed and compared in primary cultures of chick embryo dorsal root ganglion grown in serum‐free supplemented medium. In 2‐day cultures grown on type I collagen or heparan sulphate (HS)‐ collagen surfaces, ganglionic expiants exhibit a dense, symmetrical network of long, parallel neuritic processes and very few flat migrating non‐neuronal cells. In contrast, on either dermatan sulphate (DS), chondroitin‐6‐sulphate (C6S) or hyaluronic acid (HA)‐bound collagen substrates, neurons form irregular nerve fibre patterns; indeed, neuntes follow convoluted paths and often, after abrupt turns, totally reverse their direction of extension. Experiments were carried out in which a choice was given to growing neural processes between collagen or GAG‐collagen substrates. While growth cones elongating over type I collagen easily cross the border with HS‐bound collagen surface and indiscriminately extend on this substrate, in contrast, neurites generally avoid surfaces coated with DS, C6S or HA and change their direction of growth in order to stay on collagen. The binding of DS, C6S or HA, but not HS, to type I collagen thus decreases its ability to promote neurite elongation. The interaction of neuronal cells with these extracellular matrix components by restricting neurites in their paths of extension may, therefore, play a role in the patterning of the nervous circuitry.

ISSN:0736-5748    

DOI:10.1016/0736-5748(89)90060-9

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractA pure culture of oligodendrocytes has been developed starting from brain hemispheres of newborn rats. Various effects of acidic and basic fibroblast growth factors (FGFs) on the development of oligodendrocytes have been examined and compared. Both factors elicited similar effects, i.e. stimulation of the proliferation, inhibition of the specific activity of the marker enzyme 2′,3′‐cyclic nucleotide 3′‐phosphodiesterase and decrease of the ratio of myelin basic protein positive cells. These results indicate that FGFs are very potent mitogens for oligodendrocytes, even in the absence of other cell types, but that they elicit a negative effect on the cell maturation, possibly related to their strong effect on proliferation.

ISSN:0736-5748    

DOI:10.1016/0736-5748(89)90061-0

出版商:Wiley    

年代:2003

数据来源: WILEY

ISSN:0736-5748    

DOI:10.1016/0736-5748(89)90062-2

出版商:Wiley    

年代:2003

数据来源: WILEY