ISSN:0736-5748    

DOI:10.1016/0736-5748(84)90027-3

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractThe presence and storage of adrenergic neurotransmitter (monoamines) in cultured human fetal sympathetic neurons was investigated by chromate‐dichromate cytochemistry, formaldehyde‐induced fluorescence and potassium permanganate fixation. Monoamines were specifically identified in the neurons by the presence of an electron dense precipitate following cytochemical treatment. Reaction product was found in cell somas and processes in all chromate—dichromate treated cultures. The size range and morphology of the precipitate indicated a vesicular storage site within large dense core vesicles. Neurons fluoresced after treatment with formaldehyde vapors, further confirming the presence of monoamines. When potassium permanganate was employed as the fixative, occasional positive dense core vesicles were found but their frequency was greatly reduced from that seen in the chromate‐dichromate treated cultures. These findings show that cultured human fetal sympathetic neurons retain an adrenergic phenotype during long‐term serum‐free culture. In addition, the storage site for the adrenergic neurotransmitter in the developing neuron is within large dense core vesicles. The lack of dense core vesicles in potassium permanganate fixed material is believed to be due to the depletion of monoamines during fixation.

ISSN:0736-5748    

DOI:10.1016/0736-5748(84)90028-5

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractA monoclonal antibody technique has been used to locate a neural antigen which appears to be involved in developmental processes.Hybridomas were prepared using chick embryo sympathetic neurons as an immunogen and one clone, H3, was found to secrete antibodies which bound to neurons of the peripheral and central nervous system. The antibodies bound to both membrane and cytoplasmic sites of neurons but only to cytoplasmic sites of glial cells. When added to newly prepared cultures of embryonic sympathetic neurons the H3 antibodies impaired both neurite outgrowth and long‐term neuronal viability. No such effect was seen when the antibodies were added to established, differentiated neurons.

ISSN:0736-5748    

DOI:10.1016/0736-5748(84)90029-7

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractThe characteristics of taurine and hypotaurine uptake were studied during astrocyte maturation in cultures grown in normal, serum‐containing medium or in serum‐free medium in the presence of 0.1 mmol/l dibutyryl cyclic AMP (dBcAMP). The uptake of both amino acids consisted of one saturable high‐affinity component in both control and treated cultures. The dBcAMP treatment produced no marked modification of the transport systems. In the treated cultures the kinetic parameters of taurine and hypotaurine uptake remained unaltered during maturation. In the control cells the transport constant and maximal velocity of taurine uptake were greater in 21‐day‐old than in 16‐day‐old cultures, while the changes in hypotaurine transport were the opposite. The uptakes were strictly sodium‐dependent and also considerably decreased when potassium ions were omitted from incubation medium. The uptake of both amino acids was affected more by potassium omission in the dBcAMP‐treated than in the control cultures. Also the results with metabolic poisons suggest that physiological ion gradients sustained by an active Na+, K+‐pump are essential for the normal uptake of taurine and hypotaurine.

ISSN:0736-5748    

DOI:10.1016/0736-5748(84)90030-3

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractThis report documents and quantitates the naturally occurring death of neurons in the cochlear and vestibular ganglia during the normal development of the chick embryo. The data are compared with the amount of cell loss in the cochlear and vestibular nuclei to evaluate the possibility that the death of the neurons in the same sensory pathway may be related to the formation of their connections. Neurons of the cochlear and vestibular ganglia of the chick were counted and their cell bodies measured with light microscopic methods at the beginning of their period of synapse formation, embryonic day 8 (E8), at the end of the period of synapse formation (E14), and again at a more mature stage, post‐hatching day 14 (P14).The number of neurons declined between E8 and E14 in the cochlear ganglion by 25% (from 11170 to 8353) and in the vestibular ganglion by 24% (from 12687 to 9613). The neuronal population remained relatively stable between E14 and P14. Cell counts at each age were accompanied by morphological descriptions of the neurons and of their synaptic targets in the sensory epithelia of the inner ear. During the period of cell loss the mean diameters of the cell bodies in the cochlear ganglion increased slightly, from 9.5 to 111 μm and reached 17.6 μm at P14, while those in the vestibular ganglion increased from 10.4 to 13.3 μm and reached 20.9 μm at P14. The period of cell loss in the cochlear and vestibular ganglia coincides with the stages in their development when the sensory neurons have already contacted their target cells in the primary sensory nuclei and in the receptor epithelium. It is during this period that the transformation from the immature axonal endings to the definitive types of synapses begins. Thus the present data are consistent with the view that the formation of central as well as peripheral synapses is involved in determining the extent of neuronal death during the development of sensory neurons.

ISSN:0736-5748    

DOI:10.1016/0736-5748(84)90031-5

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractThe acetylcholine receptor (AChR) fromTorpedo marmorataelectric organ exists in a light form (α2βγδ) of apparent molecular weight 250,000. The association of two light forms via an intermolecular δ‐δ disulfide bridge results in the AChR heavy form. In adultTorpedoelectric organ extracts the heavy form constitutes about 70% of the AChR. We report that, in contrast, embryonic electric organ extracts contain only about 30% of the heavy form, the rest being light form. In addition, amongst a library of 38 monoclonal antibodies (mAbs), all of those that distinguished between embryonic and adult AChR did so only because they precipitated the heavy form of the AChR better than the light form.

ISSN:0736-5748    

DOI:10.1016/0736-5748(84)90032-7

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractDuring the first postnatal week hydrocortisone causes a massive increase in the number of small intensely fluorescent (SIF) cells. The purpose of the present study was to investigate whether the number of SIF cells can be increased with hydrocortisone also prenatally and after the first postnatal week.Because it was desirable to apply the same kind of treatment before and after birth, the embryos and neonatal rats were injected only once and were studied 4 days later. Pregnant rats were injected daily during the last 7 days of pregnancy and the superior cervical ganglia of their embryos were studied thereafter. After birth, the effect of 7 daily injections of hydrocortisone was also studied.The number of embryonal brightly fluorescent cells, the probable prenatal precursors of the SIF cells. could not be increased either with a single injection into the embryos, or in embryos of pregnant rats treated with hydrocortisone. A single injection of hydrocortisone into newborn and 4‐day‐old rats caused a massive increase in the number of SIF cells as studied in 4‐ and 8‐day‐old rats, respectively. The increase in the number of SIF cells was smaller but still statistically significant in 12‐day‐old rats injected with hydrocortisone on postnatal day 8. Daily injections of hydrocortisone for 7 days caused on the second, but not on the third postnatal week, a statistically significant increase in the number of SIF cells.After 7 injections of hydrocortisone. on postnatal days 3–9 or 40–46. no increase in the number of SIF cells was observed in 47‐day‐old rats, as compared with saline‐treated controls of the same age, but 7 injections of hydrocortisone both on days 3–9 and 40–46 resulted in a significant increase in the number of small intensely fluorescent cells on day 47.It is concluded that hydrocortisone‐induced increase in the number of SIF cells is limitedin vivoto the first two postnatal weeks, while exposure to hydrocortisone at birth restores the responsiveness of these cells to increase in number even later after a second exposure to hydrocortisone.

ISSN:0736-5748    

DOI:10.1016/0736-5748(84)90033-9

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractRats were bred for three consecutive generations (F1, F2, F3) on different amino acid enriched diets (tryptophan‐enriched, phenylalanine‐enriched, tyrosine‐enriched, valine‐isoleucineleucine‐enriched). The concentrations of the putative amino acid transmitters glycine, glutamate, aspartate, γ‐aminobutyric acid, and taurine were measured in the brain stem of the developing offsprings by thin layer micro‐chromatography of the dansylated amino acids. The concentrations of the investigated amino acid transmitters in the brain stem of the developing offspring of the amino acid imbalanced rats differed significantly from the values found in normal rats. The alterations from the normal developmental profiles were most pronounced in the rats bred on the valine‐isoleucine‐leucine‐enriched diet. Also the growth rate of the developing brain in each generation was affected by the different dietary amino acid supply. In the third generation at 20 days of age, with the exception of the rats bred on the tyrosineenriched diets, brain weights were generally decreased.

ISSN:0736-5748    

DOI:10.1016/0736-5748(84)90034-0

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractA previously described serum‐free, defined medium (G2 medium) containing transferrin, selenium, hydrocortisone, biotin, fibroblast growth factor (FGF) and fibronectin developed for the growth of human and rat derived glioma cells was investigated for its ability to support proliferation of astrocytes in primary cultures of neonatal rat cerebrum. These cells were able to grow in G2 medium. Enhanced proliferation and repeated subcultivation were obtained after adding insulin and/or epidermal growth factor (EGF) to the G2 medium at concentrations of 5 μg/ml and 10 ng/ml, respectively.In these modified media (called G4 and G5 medium) astrocytes showed a higher degree of morphological differentiation as compared to serum supplemented medium. Cell type specificity was determined by immunocytochemical staining of glial fibrillary acidic (GFA) protein, which could already be demonstrated 5 days after plating cells. G4 and G5 represent the first serum‐free defined media in which astrocytes proliferate and differentiate without preceding or intermediate contact to serum supplemented medium. Modification of the culture substratum by adding hyaluronic acid and chondroitin sulfate A to G4 medium (G2 medium + insulin) enhanced proliferation of astroglial cells by a factor of about 1.5. In the presence of epidermal growth factor no response to the altered culture dish surface was observed and the addition of fibronectin, otherwise a stringent plating requirement, was no longer necessary.

ISSN:0736-5748    

DOI:10.1016/0736-5748(84)90035-2

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractWe have investigated the effect of PS‐D induced in gestating rats by treatment with clomipramine or with the platform technique on the process of DNA synthesis taking place in fetal organs. This parameter was taken as a biochemical index of ongoing cellular proliferation. In brain and, to a minor extent, in liver and kidney the rate of fetal DNA synthesis was markedly increased in both experimental groups. The effect was more prominent in the clomipramine group. PS‐D treatment of gestating rats, notably by the platform technique, left long‐lasting effects in the offspring with regard to organ weight and DNA concentration as well as to learning capacity. It is concluded that the occurrence of PS in gestating rats may exert a significant influence on fetal development.

ISSN:0736-5748    

DOI:10.1016/0736-5748(84)90036-4

出版商:Wiley    

年代:2003

数据来源: WILEY