ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

One hindlimb of a rat was subjected to tourniquet compression (150, 200 and 300 mmHg; 2 h). After 6 days a 10 mm sciatic or tibial nerve graft from the compressed limb was sutured to bridge a 3–4 mm gap in the sciatic nerve of the non-compressed limb. The distances of regenerating sensory axons were measured 6 days post surgery (tibial grafts, 8 days). Compression at 200 and 300 mmHg led to significantly longer regeneration distances than those seen in controls. Incorporation of BrdU and expression of p75 receptor by non-neuronal cells (Schwann cells) in sciatic nerves 6 days after compression (150 and 300 mmHg; 2 h) was also increased as a sign of Schwann cell activation. Tourniquet compression may be used as a non-invasive method to enhance nerve regeneration in nerve grafts.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Mutations in human Cu,Zn-superoxide dismutase (SOD1) cause ≈20% of familial amyotrophic lateral sclerosis (FALS) cases. The mechanism of late-onset disease manifestation despite the innate mutation has no clear explanation. The relationship between homocysteine (HC) and amyotrophic lateral sclerosis (ALS) has not been investigated, in spite of the similarity in their pathogenesis. We investigated the effect of HC on the motor neuronal cell-line transfected with SOD1 of either wild-type or one of two mutant forms (G93A and A4 V). In the MTT assay, HC induced significant cytotoxicity in A4V, but not in G93A, as compared with wild-type, even at the physiological concentration of 10 μM. This HC-induced cytotoxicity was inhibited by the antioxidant trolox and the Cu (I) chelator bathocuproinedisulfonate. Here we show that the vulnerability of the A4 V mutant involves the cytotoxic copper-mediated pathway, and that HC may be a lifelong precipitating factor in some forms of FALS, suggesting the possible treatment modality with vitamin supplements.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Inheritance of the apolipoprotein (apoE) ϵ4 allele is a risk factor for developing Alzheimer's disease (AD). The purpose of the present study was to determine effects of apoE-isoforms on the transbilayer distribution of cholesterol in synaptic plasma membranes (SPM) using mice expressing human apoE3 and apoE4. Total SPM cholesterol levels did not differ among the wild-type and apoE3 and apoE4 knock-in mice. However, a striking difference was observed in the transbilayer distribution of SPM cholesterol. ApoE4 knock-in mice showed an ∼2-fold increase in exofacial leaflet cholesterol compared with apoE3 knock-in mice and wild-type mice. The results of this study suggest that pathogenic effects of apoE4 on AD development could be closely linked to alteration of cholesterol distribution in SPM.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Agmatine produces an antidepressant-like effect when assessed in the forced swimming test (FST) and in the tail suspension test (TST) in mice (dose range 0.01–50 mg/kg, i.p.), without accompanying changes in ambulation in an open-field. I.c.v. injection of agmatine (1–100 nmol/site) also reduced the immobility time in the FST. Agmatine significantly enhanced the anti-immobility effect of imipramine, but did not affect that of MK-801. The anti-immobility effect of agmatine assessed in the FST was not affected by pre-treatment with prazosin. In contrast, agmatine's antidepressant-like effect was completely prevented by pre-treatment of animals with yohimbine, GMP or L-arginine. Taken together these data demonstrate that agmatine elicited a significant antidepressant-like effect through a mechanism that seems to involve an interaction with NMDA receptors, the L-arginine-nitric oxide pathway and &agr;2-adrenoceptors.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Hippocampal cytoarchitectural abnormalities may be part of the cerebral substrate of schizophrenia. Amongst the chemical components being abnormal in brains of schizophrenics are altered calcium concentrations and reduced expression of the neurotrophin receptor, trkB. We studied by immunohistochemical methods the distribution of visinin-like protein-1 (VILIP-1), which is a calcium sensor protein and at the same time a trkB mRNA binding protein, in hippocampi of nine schizophrenic patients and nine matchedcontrol subjects. In normal hippocampi VILIP-1 immunoreactivity was found in multiple pyramidal cells and interneurons. A portion of VILIP-1 immunoreactive interneurons co-express calretinin (60%) and parvalbumin (<10%). In schizophrenics fewer pyramidal cells but more interneurons were immunostained. Our data point to an involvement of the protein in the altered hippocampal circuitry in schizophrenia.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The childhood spinal muscular atrophies (SMAs) are autosomal recessive neurodegenerative conditions characterized by progressive degeneration of lower motor neurons. The gene encoding NAIP (neuronal apoptosis inhibitory protein) has been proposed to be a modulator of the severity of SMA and is frequently deleted in type I SMA. In this study we have assessed NAIP (murine homologue of NAIP) transcript levels during mouse embryogenesis. NAIP mRNA is present in the developing brain and spinal cord of E9.5–E14.5 mouse embryos as detected by variousin situhybridization techniques. It is also found in the embryonic branchial arches, the nasal epithelium and in the future digits. At E16.5, NAIP mRNA transcripts were found in the marginal zone of the lateral ventricle, the follicles of the vibrissae, in the retina and in the intestinal villi. These results are the first report of NAIP gene transcript levels in embryogenesis. If motor neuron attrition occurs in the second and third trimester of gestation in SMA, the observation of NAIP transcription in the mouse spinal cord between E9.5 and E14.5 is consistent with a role for NAIP in modifying this disorder.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The functional role of BK channels, which are consistently expressed in glioma cells, is not clear. Here we show that the BK channels are regularly active in human 1321N1 astrocytoma cells at physiological membrane potentials. The proliferation of the cells at the physiological external [K+] of 5 mM is compared with that at the elevated external [K+] of 20 mM, simulating the situation in rapidly growing, necrotic tumoursin vivo. High extracellular [K+] in the range 10–30 mM significantly increases the proliferation of 1321N1 cells. This K+induced proliferation can be completely abolished by applying the specific BK channel blockers iberiotoxin (IBTX) or 1 mM tetraethylammonium (TEA). Neither blocker has any effect on cell growth at 5 mM [K+]e. These findings indicate a particular role of BK channels in astrocytoma cell proliferation.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Immunohistochemistry for calcitonin gene-related peptide (CGRP) was performed on the dorsal root ganglion (DRG) and spinal cord in wildtype and knockout mice for Brn-3a. CGRP-immunoreactive (-IR) neurons were abundant in the DRG of wildtype, heterozygous and knockout mice. Cell size analysis revealed that CGRP-IR neurons were of various sizes in wildtype and heterozygous mice. In the knockout mice, however, most of CGRP-IR neurons were small. In the spinal cord of knockout mice, the number of CGRP-IR fibers increased in the dorsal column but decreased in the deep part of the dorsal horn. The loss of Brn-3a may have different effects on CGRP-IR expression in small and large DRG neurons.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

This study was undertaken to investigate whether kainic acid (KA) may regulate the expression of several proteins which plays an important role in cell-cycle progression in cerebellar granule neurons (CGNs). KA induced decrease in MTT values in a concentration dependent way. Flow cytometric analysis showed that KA was able to induce 30% apoptosis in CGNs. Apoptotic nuclear condensation were detected 24 h of exposure to KA (200 μM). An associated marked increase in DNA synthesis, measured by BrdU incorporation, was observed. Western blot analysis showed that KA induced an increase in the expression of Cdk2, cyclin E and E2F-1. It is proposed that, in post-mitotic cells like CGNs, re-entry cell cycle could be responsible for the apoptotic effect of KA.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID