摘要:

AbstractThe gene for the mouse myelin proteolipid protein has been isolated and the seven exons have been sequenced. Since the sequence of a rat proteolipid protein cDNA and partial sequence of the human proteolipid protein gene have been determined, it was possible to demonstrate a very high degree of conservation for the protelipid protein gene exons among species. While there are some nucleotide changes, the protein coding region of the mouse gene encodes protein that is totally conserved relative to both rat and human prteolipid proteins. The regulatory and noncoding regions of the proteolipid protein gene are also highly conserved. The upstream regulatory and 5′‐noncoding region of the gene is 92% homologous to the comparable region of the human proteolipid protein gene, and the 3′‐noncoding region of the mouse gene is approximately 90% homologous to a rat proteolipid protein cDNA through 2,200 nucleotides of 3′‐noncoding DNA.S1 nuclease protection experiments indicated that the major 5′‐end for proteolipid protein mRNAs from mouse, rat human, ro baboon is approximately 147–160 nucleotides upstream from the initial methionine codon of the protein coding region. Other S1 nuclease protection experiments indicated the possible existence of an alernative splice site within exon 3, which may produce mRNA for DM20. This mRNA is approximately 100 nucleotides shorter than that for the protelipid protein, and it is missing the latter half of exon 3, that is, amino acids 116–150 of the proteolip

ISSN:0360-4012    

DOI:10.1002/jnr.490180302

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

年代:1987

数据来源: WILEY

摘要:

AbstractA full‐length clone for the human proteolipid protein (PLP) was isolated from a cDNA library constructed from poly (A)+RNA isolated from fetal spinal cords obtained at 15–24 weeks of conceptional age. The sequence of the human PLP cDNa was determined, and the deduced amino acid sequence was found to be identical with that of rat PLP. Comparison of human and rat PLP cDNA clones indicated that the coding regions retaind 97% homology and that there were also other areas of conserved sequence. The human 5′‐untranslated region was 93% homologous to that of the rat. The 3′‐untranslated region was, overall, 73% homologous to that of the rat with areas containing>84% homology in the first 400 and last 200 nucleotides. The most variability within the 3′‐untranslated region occurred between nucleotides 2,000–2,500, where homology with the rat cDNA dropped to 55%. Expression of PLP in the human spinal cord between 11 and 23 weeks after conception was examined and compared with the expression of the myelin basic protein (MBP). RNA was isolated from pooled human spinal cords obtained at three periods of development: 11–14 weeks, 17–19 weeks, and 21–23 weeks. Northern blot analysis revealed a 3.2‐kilobase (kb) PLP mRNA that was present at higher abundance in the 21–23‐week samples. The 17–19‐week RNA than in the 17–19‐week or the 11‐14‐week samples. The 17‐19–week RNA sample also contained a PLP‐hybridizing band at 2.2 kb which may possibly have arisen by utilization of alternative polysdenylation signals. Messenger RNA for MBP was detectable at 11–14 weeks but was readily evident in both the 17–19‐ and 21–23‐week age groups. Immunoblot analysis of whole spinal cord homogenates indicated that polypeptides for MBP

ISSN:0360-4012    

DOI:10.1002/jnr.490180303

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

年代:1987

数据来源: WILEY

摘要:

AbstractAstrocytes from either fetal or newborn rat brain adhered preferentially to surfaces coated with active laminin. Neurites from septal neurons did not show a preference for active over inactive laminin. However, when given a choice between laminin and an astrocytic surface, septal cells preferred to extend neurities over astroglial processes. Hence, laminin paths can guide astrocyte migration, which, in turn, can guide neurite elongation.

ISSN:0360-4012    

DOI:10.1002/jnr.490180304

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

年代:1987

数据来源: WILEY

摘要:

AbstractWe have analyzed the changes in surface antigenic properties of cerebellar bipotential precursors of oligodendrocytes and type‐2 astrocytes during their differention into oligodendrocytes in serum‐free cultures and relationship between antigen expression and proliferation of these cells. Double immunofluorescence experiments with different monoclonal fluroescence experiments with different monoclonal antibodies (mabs) performed at various stages in vitro and immunocytolysis experiments provided evidence for the following antigenic development profile: at early stages in culture the progenitor cells are recognized by the mabs A2B5 and LB1 (which bind to surface gangliosides) but not by other mabs known to label immature or mature oligodendrocytes (04, 01, and anti‐galactocerebroside [GalC]). A few days later, the precursors start to express the 04 antigen; at this stage they maintain a bipotential nature and, in the presence of serum, they differentiate into type‐2 astrocytes. If maintained in serum‐free medium, the progenitor cells enter the oligodendrocyte differentiation compartment, acquiring GalC postivity. Soon after compartment GalC+, the cells lose both bipotentiality and the surface antigens binding A2B5 and LB1. They conserve, however, the antigen binding 04. Experiments of [3H]thymidine autoradiography combined with immunofluorescence showed that a greater proportion of the LB1+cells incroporated the radioactive nucleoside into their nuclei as compared to the 04+cells. No incorporation was present in GalC+oligode

ISSN:0360-4012    

DOI:10.1002/jnr.490180305

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

年代:1987

数据来源: WILEY

摘要:

AbstractWe have recently reported the immunolocalization of nerve growth factor (NGF) in mouse kidney by light microscopy. In the present study, we have investigated the ultrastructural localization of NGF by the preembedding immunoperoxidase method for electron microscopy. NGF immunoreactivity was present in the connecting tubule cells of the distal nephron. These cells showed immunostaining associated with the Golgi complex, vesicles, rough endoplasmic reticulum (RER), and polyribosomes. The intercalated cells, in contrast, lacked immunoreactivity.

ISSN:0360-4012    

DOI:10.1002/jnr.490180306

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

年代:1987

数据来源: WILEY

摘要:

AbstractA chloride‐dependent transport process for glutamate has been identified in partially purified rat brain synaptosomes. This process shares many characteristics with the chloride‐dependent sequestration process for glutamate in brain sonicates, which was previously thought to represent a quisqualate receptor, such as sensitivity to specific inhibitors and regulation by anions. Increases the concentrations of chloride led to and increase in the apparent Vmaxwithout affecting the KT. Synaptosomes preincubated with [3H]‐L‐glutamate exhibit an efflux of the radiolabel, which was stimulated by a substrate for the carrier in the incubating medium, indicating the bidirectional nature of the transport. The chloride‐dependent transfer process is restricted to the brain, and regional and developmental profiles clearly distinguish it from the sodium‐dependent high‐affinity uptake process for glutamate. Nevertheless, the effects of excitotoxic lesions strongly suggest a neuronal localization of the chloride‐depe

ISSN:0360-4012    

DOI:10.1002/jnr.490180307

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

年代:1987

数据来源: WILEY

摘要:

AbstractPrimary dispersed cell cultures were established from fetal diencephalic tissue derived from two stocks of outbred rats. The overall growth pattern, as followed by phase‐contrast microscopy and visualized by immunocytochemistry for neurofilament proteins and neuron specific enolase, depended on the age of the donor animal. Stock differences were not revealed by these methods. In contrast, when the cultures were immunostained in order to assess the yield of a specific type of cell, i.e., magnocellular hypothalamic neurons, striking differences were observed between the two stocks of rats. Whereas neurophysin‐immunoreactive cells could be grown in culture established from fetal Chbb: Thom rats at embryonic days 14, 15, and 18, no such cells could be detected in cultures derived from CrI: CD (SD) BR rats older than embryonic day 14. These findings may reflect differences in the differentiation schedule and/or requirements for certain epigenietic and trophic factors between magnocellular neuroblasts derived from the two stock of r

ISSN:0360-4012    

DOI:10.1002/jnr.490180308

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

年代:1987

数据来源: WILEY

摘要:

AbstractAn increase in neurotrophic activity for the survival of dissociated sensory neurones has been found in the spinal cord of morphine dependent rats. This activity is not due to morphine itself and is not due to an increase in the nerve growth factor as antibodies to nerve growth factor fail to block the response. A new hypothesis is presented that some of the spinal effects of morphine dependence may be due to and increase in the level of neurotrophic factors as a response to an apparent denervation of the target cells in the spinal cord.

ISSN:0360-4012    

DOI:10.1002/jnr.490180309

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

年代:1987

数据来源: WILEY

摘要:

AbstractPeripheral nerve section causes a degenerative atrophy of substance P sensory input and of met‐enkephalin interneurons in the dorsal horn of the spinal cord. Radioimmunoassay of both peptides indicates that the decrease in peptide levels ranges from 30 to 50%, that it occurs several days after lesioning, and that it is simultaneous for the two peptides. Quantitative immunocytochemistry performed by computer‐assisted analysis of met‐enkephalin‐positive boutons shows that following sciatic nerve lesions there is a decresed density of immunoreactive boutons per unit area in densit of immunoreactive boutons per unit area in the substantia gelatinosa of the dorsal horn in the lumbar cord ipsilateral to the lesion. Within 24 h of nerve injury there is a significant and transient enhancement of serotonin turnover, as indicated by the increased levels of 5‐hydroxyindolacetic acid in the lumber cord, without any change in serotonin concentrations. The restoration of normal serotonin metabolism at d 10 postlesioning coincides with the peptidergic loss. However, if, prior to nerve resection, serotonin stores are depleted by p‐chlorophenylalanine treatment, the damage to met‐enkephalin interneurons in fully prevented, while substance P loss does still occur. These results suggest that signals caused by the section of a peripheral nerve are directly responsible for substance P loss in the spinal cord and are, presumably, rapidly transported into the CNS, causing an activation of the serotoninergic raphe neurons projecting to spinal cord. The activation of this system is likely responsible for the degenerative atrophy of the met‐enkephalin interneurons. These results further confirm our previus suggestion (Di Giulio et al: Peptides 6:24–256, 1985;Brain Res342:405–408, 1985) that the peptidergic loss induced by perpheral nerve section may be intraspinally regulated, and that pain sensations which develop after nerve lesions may be related to intraspinal alterations, such as the atrophy of met‐enkephalin‐containing interneurons, rather than to the formation of a large neuroma by the injured axons. As a matter of fact the increased serotonin turnover is triggered within 24 h, while neuroma formation requires several days

ISSN:0360-4012    

DOI:10.1002/jnr.490180310

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

年代:1987

数据来源: WILEY

摘要:

AbstractThe effects of electroconvulsive shock (750 msec, 130 V, 150 pps) on the endogenous content of rat cerebral lipids were studied 2, 5, 10, 20, 30, 60, and 300 sec after stimulation. Rapid enzyme inactivation in situ was attained by high‐power head‐focused microwave irradiation (6.5 kW, 2450 MHz). At 10 sec, phosphatidylinositol 4,5‐bisphosphate (PIP2) mass had decreased by 249 nmol per g wet wt, mainly due to loss of arachidonate and stearate. At the same time, the stearoyl‐arachidonoyl glycerol accumulated, although to a lesser extent than the loss exhibited in PIP2. Changes in phosphatidylinositol and in phosphatidylinositol 4‐phosphate mass were not statistically significant. Free fatty acids and diacylglycerold accumulated to 395 nmol per g wet wt; arachidonic and stearic acids composed 322 nmol of these lipids. Hence, the reduction in content PIP2is sufficient to account 80% of the increases in free fatty acid and diacylglycerol mass. Thirty‐three and 12 nmol of accumulated free palmitic and scosahexaenoic acids, respectively, are not accounted for by the loss of PIP2. Sixty seconds after stimulation, PIP2content returned to 90% of control levels, while diacylglycerol tended to remain below control levels. Free fatty acids had not returned to control levels by 60 sec, with the exception of docosahexaenoic acid. At 300 sec, PIP2, diacylglycerol, and free fatty acids had all returned to control levels. It is proposed that the elctroshock‐induced release of neurotransmitters is associated with stimulation of phospholipases A1and A2at the presynaptic membrane followed by receptor‐linked phosphodiesteratic cleavage of PIP2at the postsynaptic membrane, and that Ca2+influx resulting from membrane depolarization activates the deacylation of stearoyl‐arach

ISSN:0360-4012    

DOI:10.1002/jnr.490180311

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

年代:1987

数据来源: WILEY