摘要:

AbstractPrevious work has demonstrated that white matter in the adult mammalian CNS inhibits cell adhesion and neurite outgrowth. This phenomenon has been investigated most recently by culturing neurons on cryostat sections of the adult CNS. Employing this same technique, we have found, in accord with others, that neurons seldom adhere to or grow on central nervous system white matter but will attach and grow on gray matter. In the experiments presented here, embryonic rat hippocampal neurons were grown on cryostat sections from the adult rat CNS, in the presence of brain derived glial cocultures. It was found that the white matter in cryostat sections can be modified by interaction with medium conditioned by brain‐derived glial cells. Neurons plated on sections pretreated by such media show significant increases in both attachment and neurite outgrowth. The activity contained in glial conditioned medium is likely complex in nature. While the majority of the activity can be eliminated by heat treatment and trypsinization, neural adhesion but not neurite initiation is affected by protease treatment. Therefore, cell attachment and neurite outgrowth may be regulated by different factors in the conditioned media. © 1994 Wiley‐Liss,

ISSN:0360-4012    

DOI:10.1002/jnr.490370103

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

年代:1994

数据来源: WILEY

摘要:

AbstractSJL/J mice were immunized with human PLP as well as encephalitogenic PLP peptides 139–151 and 178–191 and the resulting antibody responses examined for immunochemical specificity employing a panel of 17 synthetic PLP peptide ligands. All animals had demonstrable circulating titers of antibodies early in the humoral immune response to their respective encephalitogens, however, there was no clear qualitative correlation between antibody responses and the induction of EAE. In the majority of PLP immunized animals, determinant‐specific antibody populations, including those against encephalitogenic centers, were not detectable in the presence of an anti‐PLP antibody response. Antiencephalitogenic peptide antibodies were present in both 139–151 and 178–191 immunized animals regardless of clinical/histologic status. Neither group produced cross‐reactive anti PLP antibodies as detected by ELISA. In animals immunized with peptide 139–151, only anti‐139–151 antibody specificities were noted. In contrast, all animals immunized with peptide 178–191 had an antibody population cross‐reactive with three other PLP peptides: 97–110, 209–217, and 215–228. As humoral immune responses can be demonstrated against PLP‐specific encephalitogenic epitopes, the significance of these B cell responses should be considered in the context of their potential role in the development, modulation, and/or potentiation

ISSN:0360-4012    

DOI:10.1002/jnr.490370104

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

年代:1994

数据来源: WILEY

摘要:

AbstractSchwann cells support and facilitate axonal growth during development and successful regeneration in the peripheral nerve. In the regenerating rat sciaticnerve, Schwann cells provide a trophic milieu for primary sensory, sympathetic, and motoneurons. We have characterized a neurotrophic activity produced by adult rat sciatic nerve Schwann cells and a spontaneously immortal Schwann cell clone (iSC). This activity elicits neurite outgrowth from chick embryo explants of both CNS and PNS. The iSC activity has been concentrated by cation‐exchange chromatography and compared to known neurotrophins in bioassay. Pooled bound fractions elicit neurite outgrowth from sympathetic, ciliary and motoneurons. In collagen matrix cocultures of iSC and E4 ventral horn(before motor axon extension to muscle targets), the iSC activity can direct the initial axonal extension from motoneurons. The data presented suggest that Schwann cell‐produced activity may mediate motoneuron axonal extension before contact with their peripheral source of neurotrophin. © 1994 Wiley‐Lis

ISSN:0360-4012    

DOI:10.1002/jnr.490370105

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

年代:1994

数据来源: WILEY

摘要:

AbstractDetermination of the topographic orientation of proteolipid protein (PLP) within myelin is part of an overall understanding of the functions of PLP and the roles of its multiple domains in diseases that primarily affect central nervous system (CNS) myelin. As part of an analysis of PLP orientation, two mouse monoclonal antibodies (mAb) and a rabbit antiserum against a synthetic peptide corresponding to PLP residues 103–116 (YKTTICGKGLSATV) were tested for their reactivity on compact CNS myelin. By ELISA, the antibodies react with intact PLP and PLP residues 103–116, but not with other PLP peptides. Ultrathin cryosections of adult rat optic nerve were immunostained and antibody binding was localized using appropriate second antibodies coupled to 1 nm gold particles that were visualized by silver enhancement. Localization of the particles on the major or intermediate dense lines was determined by three in dependent observers. Using the PLP peptide mAb and the polyclonal antibody, we demonstrated that ≥71% of the particles were localized on the major dense line. At least 66% of particles directed against myelin basic protein, which is known to occur on the major dense line, were also found in that location. These semiquantitative morphologic observations suggest that PLP residues 103–116 occur on the cytoplasmic face of the myelin membrane. © 1994 Wiley

ISSN:0360-4012    

DOI:10.1002/jnr.490370106

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

年代:1994

数据来源: WILEY

摘要:

AbstractHeat‐induced expression of 72‐kDa heat shock protein (HSP72) was investigated in a panel of neuronal and non‐neuronal cell lines by immunoblotting and immunocytochemistry using monoclonal antibodies directed to HSP72. By immunoblotting, HSP72 expression was observed in most cell lines of mouse (SN6.1b, CL8c4.7, NSC34.6, B2A, C2C12), RAT (PC12, C‐6, L3), and human (NB‐1, GOTO, IMR‐32, Hela) origin under the heat‐stressed condition. The mouse neuroblastoma cell line N18TG2, however, did not express HSP72 under the heat‐stressed condition. By immunocytochemistry, HSP72 was undetectable in the heat‐stressed N18TG2 cells, while it was identified in the heat‐stressed SN6.1b cells, a clonal hybrid neuron between N18TG2 and mouse septal cholinergic neuron. By exposure to a priming sublethal heat shock, SN6.1b cells but not N18TG2 cells acquired a significant level of tolerance to a subsequent lethal heat shock. These results suggest that heat‐induced expression of HSP72 may contribute to acquisition of the thermotolerant state in SN6.1b cells.

ISSN:0360-4012    

DOI:10.1002/jnr.490370107

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

年代:1994

数据来源: WILEY

摘要:

AbstractPlatelet‐activating factor (PAF, 1‐O‐alkyl‐2‐acetyl‐sn‐glycero‐3‐phosphocholine), undetectable in resting neural tissue, accumulates in brain during seizures. A hetrazepine, BN‐50730, is shown here to displace [3H]PAF‐specific binding from microsomal, but not from synaptosomal membranes, indicating selectivity for a high affinity intracellular binding site. Rats pretreated with BN‐50730 by intraperitoneal or intracerebroventricular injection exhibited an inhibition of the electroconvulsive shock (ECS)‐induced expression of c‐fosandzif‐268 in hippocampus. A much more pronounced, dose‐dependent inhibition of ECS‐inducedzif‐268 mRNA in hippocampus by intracerebroventricular injection of of BN‐50730 was observed. It is concluded that, in the hippocampus, PAF IS A MEDIATOR OF THE EXPRESSION OFzif‐268 and, to a lesser extent, c‐fosthrough an intracellular specific binding site. Thus, PAF may be a messenger in signal regulated zinc‐finger transcription factors, and in other immediate‐early genes involved in long‐term syna

ISSN:0360-4012    

DOI:10.1002/jnr.490370108

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe neurotoxic effects of oxygen radical on spinal cord neuron cultures derived from fetal mouse have been studies. Oxygen radicals, superoxide radical and hydrogen peroxide, were generated by adding xanthine oxidase and hypoxanthine in the culture medium. Exposure of neurons to this oxygen radical generating system resulted in a significant cell death and decrease of choline acetyltransferase (ChAT) activity in a time‐dependent manner in spinal cord neuron cultures. The decrease in cell viability and ChAT enzyme activity induced by the oxygen radicals was blocked by scavengers such as superoxide dismutase (SOD), catalase, and tetrakis (2‐pyridylmethyl) ethylenediamine (TPEN), a metal chelator. Antagonista of theN‐methyl‐D‐aspartate (NMDA) receptor, including MK801 (a noncompetitive NMDA antagonist),D‐2‐amino‐5‐phosphonovaleric acid (APV) (a competitive NMDA antagonist), and 7‐chlorokynurenic acid (an antagonist at the glycine site associated with the NMDA receptor), similarly blocked oxygen radical‐induced decrease in cell viability and ChAT activity in spinal cord neuron cultures. These results indicate that both oxygen radicals and excitotoxic amino acids were involved in the oxidant‐ititiated neurotoxicity of spinal cord neurons.

ISSN:0360-4012    

DOI:10.1002/jnr.490370109

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

年代:1994

数据来源: WILEY

摘要:

AbstractTreatment of PC12 cells with Bay K 8644 for 12 hr or more leads to an almost 80% decrease in the subsequent ability of Bay K 8644 to stimulate the uptake of radioactive calcium into the cells. This effect is a property of the s(−)isomer of Bay K 8644; pre‐treatment with the R(+)isomer, now known to be a calcium channel blocker, has the opposite effect. This treatment is specific in that is does not intergfere with the stimulation of calcium uptake by potassium, ATP, or nerve growth factor. Such treatment is accompanied by a 90% decrease in the ability of Bay K 8644 to stimulate the release of norepinephrine. The characteristics of the binding of [3H]isradipine to control and to treated cells indicates that the decrease in the effect of dihydropyridines is accompanied by a marked decrease in the number of dihydropyridine binding sites with no apparent change in the affinity of the remaining sites. The continued ability of depolarizing levels of potassium to stimualte calcium uptake and the induction of the protooncogene c‐fos in Bay K 8644‐treated cells indicates that the L‐type calcium channels are still intact, but are simply unresponsive to dihydropyridine agonists. © 1994 Wiley‐Liss, Inc.This article is a US Government work and, as such, is in the public domain in the United State

ISSN:0360-4012    

DOI:10.1002/jnr.490370110

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe regulation of phosphoinositidase C (PIC) activity by guanosine‐5′‐(3‐O‐thio)triphosphate (GTPγgMS) was characterized in a cholate‐solubilized peripheral myelin‐enriched fraction from rat sciatic nerve. The GTP analog maximally enhanced PIC‐catalyzed hydrolysis of exogenous phosphatidylinositol‐4,‐5‐bisphosphate (PIP2) in a dose‐dependent manner only within a narrow range of cholate concentrations. Maximal stimulation was attained at 0.6 μM GTPγS and could be completely prevented by 1 μM guanosine‐5′‐(2‐O‐thio)diphosphate. Neither adenylyl‐imidodiphosphate nor adenosine triphosphate (ATP) enhanced PIC activity. Carbamoylcholine (1 mM)added together with GTPγS increased the extent of PIP2hydrolysis over that elicited by GTPγ increased the extent of PIP2hydrolysis over that elicited by GTPγS alone and this stimulation was blocked by the muscarinic receptor antagonist, atropine (50 μM). In detergent solubilized myelin preparations from streptozotocin induced diabetic rats, a higher concentration of the guanine nucleotide analogn was required to achieve stimulation comparable to that obtained with corresponding preparations from normal animals. These results suggest that sciatic nerve myelin possesses muscarinic receptors coupled via a GTP‐binding protein to PIC and that this system can be reconstituted in detergent‐solubilized extracts. It is possible that the function of G Proteins in cell signaling is impaired in experimen

ISSN:0360-4012    

DOI:10.1002/jnr.490370111

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe neuroprotective properties of acetyl‐L‐carnitine (ALCAR) were investigated in primary cell cultures from rat hippocampal formation and cerebral cortex of 17‐day‐old rat embryos. Chronic exposure to ALCAR (10–50 μM), reduced the cell mortality induced by 24 hr fetal calf serum deprivation. Protection was partial when the neuronal cells, chronically treated with ALCAR (50 μM,) were exposed to glutamate (0.25‐1 mM)and kainic acid (250–500 μM) for 24 hr. The neurotoxity induced by N‐methyl‐D‐aspartate (NMDA, 250 μm) was attenuated by the acute co‐exposure with ALCAR (1mM), the chronic treatment with ALCAR (50 μM)significantly reduced the neuronal death induced by NMDA (0.25–1mM) Cell mortality was also investigated in ALCAR‐treated hippocampal cultures chronically treated with β‐amyloid fragment 25–35. ALCAR appeared to have neuroprotective activity. This suggests an explanation of the positive results obtained with ALCAR in the treatment of alzheime

ISSN:0360-4012    

DOI:10.1002/jnr.490370112

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

年代:1994

数据来源: WILEY