摘要:

AbstractThe ultrastructural localization of phenylethanolamine N‐methyltransferase (PNMT), the enzyme used in the final step in the synthesis of adrenaline, was examined in the medial nuclei of the solitary tracts (m‐NTS) and in the dorsal motor nuclei of the vagus. Adult rats were anesthetized with Nembutal (50 mg/kg intraperitoneally), and the brains were fixed by vascular perfusion with a solution containing 3.75% acrolein and 2% paraformaldehyde in 0.1 M phosphate buffer. Coronal Vibratome sections were collected through the intermediate portions of the m‐NTS at the level of the area postrema. These sections were immunocyto‐chemically labeled employing a rabbit polyclonal antiserum against PNMT and the peroxidase‐antiperoxidase method. Immunoreactivity was detected in perikarya, dendrites, and axon terminals in the intermediate portion of the m‐NTS. The labeled perikarya were either small (10–15 μm diameter) and oval or large 20–30 μm) with two or more proximal processes. The PNMT‐containing dendrites received synaptic input from unlabeled, small (0.5–1.0 μm) and large (2–3 μm) vagal‐like afferents as well as from a few terminals, which also showed PNMT immunoreactivity.Axons and axon terminals containing immunoreactive PNMT were more frequently observed than the perikarya or dendrites in the m‐NTS and were the only labeled profiles in the dorsal motor nuclei. In both regions the PNMT‐labeled terminals formed principally symmetric synapses with unlabeled dendrites. However, a few asymmetric axodendritic and symmetric axosomatic synapses also were detected. These findings indicate that the adrenergic neurons may have multiple, but principally inhibitory, actions on other neurons within cardiovagal

ISSN:0360-4012    

DOI:10.1002/jnr.490150402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractA partially purified myelin basic protein serum factor (MBP‐SF), cross‐reactive with residues 65–74 (TTHYGSLPQK) of myelin basic protein, has been employed in an immunochemical study to identify the nature of the cross‐reacting determinant, more precisely. To probe the structural requirements of this determinant, Scatchard inhibition analyses and competitive peptide inhibition radioimmunoassays were employed with a series of peptide analogs of the 65‐74 region and with three different reagent antisera: a rabbit anti‐rat myelin antiserum (#My05) and two antisera, one rabbit (#162) and one chicken (#66), raised against synthetic peptide S24 (TTHYGSLPQKG). Scatchard inhibition analyses with MBP‐SF revealed specific inhibition of binding of125I‐S24 to #162 and #My05, butnotto #66. Further delineation of the structural requirements of the cross‐reactive determinant, employing a liquid‐phase radioimmunoassay, revealed a unique reactivity pattern for the chicken anti‐S24 antiserum which, unlike #162 and #My05, did not cross‐react under high‐affinity conditions with synthetic peptide S20 (GSLPQK, representing the C‐terminal half of S24). This, in concert with the Scatchard data, is suggestive of the presence of a cross‐reactive determinant centered

ISSN:0360-4012    

DOI:10.1002/jnr.490150403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractThe effect of exogenous monosialo ganglioside GM1on neurotoxin‐induced lesioning of bulbo‐spinal serotonergic neurons of newborn rats was studied by means of biochemical and immunocytochemical techniques. 5,7‐dihydroxytrypatamine (5,7‐HT, a selective serotonin neurotoxin) treatment of newborn rats caused a pronounced reduction of 5‐hydroxytryptamine (5‐HT) and 5‐hydroxyindoleacetic acid (5‐HIAA) levels in the thoracic and lumbar spinal cord, while an increase of 5‐HT and 5‐HIAA was found in the pons medulla. These biochemical alterations were regionally correlated with similar changes in 5‐HT nerve terminal density analyzed by image analysis. GM1administration (30 mg/kg for 4 consecutive days) antagonized the reduction of 5‐HT and 5‐HIAA levels induced by 5, 7‐HT treatment in the lumbar spinal cord of 2‐month‐old rats, as well as the decrease of 5‐HT nerve terminal density in both thoracic and lumbar spinal cord of 1‐ and 2‐month‐old rats. A minor counteracting effect of GM1was found in the pons medulla where the neurotoxin induced an increase of 5‐HT and 5‐HIAA levels. These data support the hypothesis that GM1may have a preventing action on retrograde degenerative processes following chemical lesion and/or a growth

ISSN:0360-4012    

DOI:10.1002/jnr.490150404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractThe ependymal cells in rat host spinal cord were studied after transplantation of fetal cerebral cortex homografts. Adult Sprague‐Dawley male rats had pieces of E14 fetal rat cortex pressure‐injected into the spinal cord at T6. The tissue was prepared for light and electron microscopy and studied for over 2 months postimplantation. At 7 and 14 days postimplantation (DPI), there were dividing ventricular‐ependymal cells lining cysts in the host spinal cord. After 21 days, cell division was no longer observed in these cells, and only mature ependymal cells lined these cysts. Mature ependymal cells were either: columnar, pseudocolumnar, cuboidal, squamous, or pseudomorphic; had cilia and villi on only one surface of the cell and shared tight junctions when contiguous. These data show that ependymal cells were mature cellular components of adult spinal cord after transplantation of fetal CNS grafts. In addition, ventricular‐ependymal cells continued to divide within the parenchyma of the graft, indicating continued growth of transplanted fetal cerebral cortex in host spin

ISSN:0360-4012    

DOI:10.1002/jnr.490150405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractThe mechanisms of presistence and of demyelination in Theiler's virus (TV)‐induced chronic neurologic disease (a murine model for multiple scelerosis) are, as yet, disputed. We investigated the tropism and persistence of TV in brain cell culture to better understand the pathogenesis of this disease. Using anti‐genic markers to identify specific cells in culture, we have demonstrated that TV infects, lytically, neurons and oligodendrocytes and persistently astrocytes and macrophages. These results suggest that host cell factors play a key role in the mechanism of demyelination and the persistence of TV in the nervous sys

ISSN:0360-4012    

DOI:10.1002/jnr.490150406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractRecent studies have suggested that cell to cell communication in the immune system is mediated by cell surface receptors for glycosaminoglycans (GAGs) [Parish et al, 1984]. The intention of this study was to see whether similar recognition molecules for GAGs are present on sympathetic neurones. A mechanical dissociation technique was used to isolate neurones from superior cervical ganglia (SCG) of rats aged between gestational day 19 and postnatal day 21. Receptors for GAGs on sympathetic neurones were detected by the ability of neurones to form rosettes with sheep red blood cells coupled with one of 12 different GAGs. It was found that SCG cells bind to all the GAGs tested. In addition, a range of developmental binding patterns for the various GAGs was found.

ISSN:0360-4012    

DOI:10.1002/jnr.490150407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractMonoclonal antibodies selectively reacting with the high molecular weight neurofilament proteins (NF 150K and NF 200K) on immunoblots of bovine spinal cord extracts were obtained upon immunization of mice with chicken brain antigen and with highly purified NF 150K or NF 200K isolated from bovine spinal cord by anion exchange chromatography. Antibodies reacting with NF 200K or with both NF 150K and NF 200K were selected for this study. The antibodies were screened on immunoblots for reactivity with phosphorylated epitopes by dilution of the supernatants in sodium potassium phosphate as well as by treatment of nitrocellulose transfers with alkaline phosphatase. Abolishment of staining under these conditions was taken as evidence of reactivity with phosphorylated epitopes. With phosphate/phosphatase‐sensitive antibodies, NF 200K immunoreactivity was a late event in rat optic nerve development. It was first observed at day 18 on immunoblots of sodium dodecyl sulfate extracts analyzed by gel electrophoresis. Conversely, with phosphate/phosphatase‐insensitive antibodies, NF 200K immunoreactivity was already present on day 10, the earliest age in this study. With one monoclonal reacting with phosphorylated NF 150K and NF 200K, NF 150K immunoreactivity was already present on day 10. It is proposed that NF 200K expression precedes NF 200K phosphorylation in developm

ISSN:0360-4012    

DOI:10.1002/jnr.490150408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractMyelin basic protein (MBP) is one of the most important myelin components. Based on our previous studies, we hypothesized that neurons might have regulatory effects on the production of MBP by oligodendrocytes, and we conducted studies designed to verify this hypothesis. Oligodendroglia‐rich cultures from total brain of neonatal rats or mice and pure cultures of embryonic rats or chicks were prepared. Cultures of mouse fibroblasts and astrocytes were prepared as well. We show here that MBP production by oligodendrocytes was greatly enhanced by treatment with either pure neurons, rat neuronal conditioned medium, or chick neuronal conditioned medium, while chemically defined, hormonally supplemented medium or medium conditioned by astroctyes and fibroblasts had no effect on MBP expression. We conclude that the production of MBP by oligodendrocytes is regulated by a nonspecies specific soluble neuronal factor. The conservation of this phenomenon from avian to rodent species implies its critical role in myelination and suggests its potential application as a treatment in demyelinatio

ISSN:0360-4012    

DOI:10.1002/jnr.490150409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractEmbryonic chick skeletal myotubes grown in cell culture require transferrin to provide iron for proliferation and differentiation. We demonstrate here that cultured myotubes contain transferrin receptors as demonstrated by the finding of specific, saturable, and reversible high‐affinity binding sites. Scatchard analysis of equilibrium binding data indicates an apparent Kdof 37 nM and one muscle cell equivalent contains 7,500 transferrin receptors. Myotubes exhibit a Kd100 times higher for apotransferrin than for iron‐saturated transferrin.Internalization of specifically bound transferrin is temperature dependent and occurs rapidly at 37°C with a steady state reached after 10 min. Internalization studies using either125I‐ovotransferrin or55Fe‐ovotransferrin suggest that transferrin is internalized, depleted of iron, and recycled intact to the extracellular medium as shown in other cell systems. Autoradiography of muscle cell cultures incubated with125I‐ovotransferrin at 4°C reveals clusters of receptors along the myotubes.The possible mechanisms by which transferrin is supplied to muscle in vivo are discussed in light of the evidence that motor neurons contain

ISSN:0360-4012    

DOI:10.1002/jnr.490150410

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractThe high molecular weight microtubule‐associated proteins (MAPs) consist of MAPs 1A, 1B, 1C, 2A, and 2B. The proteins have been prepared from rat brain by using taxol and resolved by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis. The individual proteins were purified by electro‐elution from stained fixed gels and shown to migrate at their original mobility without proteolysis. Amino acid compositions of purified MAP 1 and 2 component proteins are reported and com

ISSN:0360-4012    

DOI:10.1002/jnr.490150411

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY