摘要:

Cortical infarction produces secondary neuronal damage in the thalamus. In this study we examined the thalamus of the rat following 2 h occlusion of the middle cerebral artery (MCA), and found degeneration and gliosis in the ipsilateral ventropostero-medial thalamic nucleus in those rats that showed cortical infarction 7 and 14 days after occlusion. This was accompanied by isolated cells with fragmented DNA, as revealed byin situlabelling of nuclear DNA fragmentation, and showing morphological features of apoptosis, i.e. chromatin condensation, extreme nuclear shrinkage and apoptotic bodies. In addition, cells immunoreactive for c-Jun showing morphological signs of apoptosis were observed. These results provide evidence of apoptosis in the ipsilateral thalamus following cortical infarction, and suggest that c-Jun is involved in this process.

ISSN:0959-4965    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Pretreatment by a sublethal insult is associated with induction of stress proteins and with protection from subsequent injury. Heat pretreatment protects the brain from subsequent ischemia, and is shown here to protect primary astrocyte cultures from subsequent oxygen-glucose deprivation. To determine whether the expression of a single stress protein, HSP-70, could account for much of this protection, we expressed HSP-70 or β-galactosidase in astrocytes using retroviral vectors. Only 12% of astrocytes expressing HSP-70 died after 7 hours of oxygen-glucose deprivation compared to 65% of astrocytes expressing β-galactosidase and 82% of normal astrocytes. Our data provide direct evidence that selective expression of HSP-70 enhances the survival of astrocytes challenged with heat or oxygen-glucose deprivation.

ISSN:0959-4965    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

The HIV-1 envelope protein gp120 produces neuronal cell damage in primary cultures of a variety of cell types including hippocampal and retinal ganglion cell neurons. The properties of primary cell cultures are, however, often markedly different from those of cells living in their normal environment. We now report that gp120 induces widespread chromatin condensation and lesions in pyramidal granular neurones and in interneurones of rat hippocampal organotypic slice cultures. This damage is clearly of an apoptotic (programmed cell death) type. The use of anin vitroorganized structure will enable the molecular and cellular mechanism of action of gp120 to be examined in conditions which are particularly suitable and relevant to thein vivosituation.

ISSN:0959-4965    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Cell death and neurofibrillary tangle formation are prominent features of Alzheimer's disease (AD). It has been suggested that DNA damage may reflect neuronal vulnerability. In this context, the Ced homologue Bcl-2 is able to repress a number of cell death programs. Recently we found both numerous nuclei exhibiting DNA damage within neurons in the AD brain and increases in Bcl-2 immunoreactivity. In this study, we examined the relationship between Bcl-2 expression and nuclear DNA damage or tangle formation. Nuclei exhibiting DNA damage were associated with an up-regulation of Bcl-2 expression, whereas tangle-bearing neurons were associated with a down-regulation of Bcl-2 expression.

ISSN:0959-4965    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

L-DOPA kills dopamine neurones in culture but is the most effective drug for the treatment of Parkinson's disease, where it exhibits no clear toxicity. While glial cells surround and protect neuronesin vivo, neurones are usually culturedin vitroin the absence of glia. We treated fetal midbrain rat neurones with L-DOPA, mesencephalic glia conditioned medium (CM) and L-DOPA + CM. L-DOPA reduced the number of tyrosine hydroxylase-positive (TH+) cells and [3H]DA uptake, and increased quinone levels. L-DOPA + CM restored [3H]DA uptake and quinone levels to normal, and increased the number of TH+cells and terminals to 170% of control. CM greatly increased the number of TH+cells and [3H]DA uptake. Mesencephalic glia therefore produced soluble factors which are neurotrophic for dopamine neurones, and which protect these neurones from the toxic effects of l.-DOPA.

ISSN:0959-4965    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

The left vagus nerve was stimulated during transient forebrain ischaemia in gerbils. The animals were exposed to 3 min of forebrain ischaemic insult at 37.5 C. On day 5 post-ischaemia, the animals were perfusion-fixed for qualitative and quantitative histopathological analyses. High current stimulation of the vagus nerve inhibited ischaemic neuronal damage in the hippocampal CA1 sector (p < 0.01), but low current stimulation did not (p < 0.01). These effects might have been due to inhibition of the effects of excitatory amino acids during ischaemia. These results indicate that vagus nerve stimulation might be protective to neurones subjected to ischaemic insult.

ISSN:0959-4965    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

To examine our hypothesis that dopamine activity in the lateral hypothalamic area (LHA) may play a role in enhancing the process of eating, a fetal cell suspension of predominantly dopaminergic cells was bilaterally transplanted into the LHA of study rats via direct injection; controls had carrier medium injection. Thereafter, mean daily food intake was 1 g per day greater in dopaminergic cell transplanted rats vs. controls for each day of the 10-week observation period. This resulted in a significantly greater cumulative body weight gain in study rats vs. controls (386 ± 5.1 g vs. 354 ± 3.8 g, respectively). On sacrifice at the end of the study, transplanted cells in the LHA were viable. Our data suggest that bilateral LHA dopaminergic cell transplant which presumably resulted in chronically and persistently enhanced dopaminergic activity in the LHA is associated with overeating and consequently, an excess weight gain.

ISSN:0959-4965    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Intracellular techniques were used to study the actions of dopaminergic D1agonists on the afterhyperpolarization (AHP) that follows action potentials in rat neostriatal neurones. Dopamine or Cl-APB (10 μM), or 1–10 μM 6-C1-PB all increased AHP amplitude. This effect was blocked by 1 μM SCH-23390, a D1antagonist, but not by 1 μM sulpiride, a D2antagonist. Both 500 μM dibutyryl cAMP and 5 μM BayK 8644 induced a similar AHP increase. BayK 8644 occluded the effect of agonists. The results suggest that the action of dopamine is mediated via the recently described protein kinase A enhancement of L-type Ca2+channels. The results partially explain the decrease in firing frequency induced by dopamine and a possible site of antagonism with cholinergic modulation.

ISSN:0959-4965    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Altered dopamine (DA) transporter densities have been implicated in mechanisms of vulnerability and relapse in human alcoholics. The regional distribution and density of the DA transporter was studied in alcohol-preferring vervet monkeys to investigate baseline status and regulation of the DA transporter at different stages of chronic alcohol drinking. Combined ligand binding andin vitroautoradiography of the cocaine congener [125I]RTI-55 (β-CIT) demonstrated a significant increase in DA transporter densities in abstinent alcohol-preferring monkeys over those in alcohol-avoiding monkeys. Chronic alcohol consumption down-regulated DA transporter densities, and this effect was reversed by acute withdrawal. These results demonstrate that the DA transporter is regulated by alcohol exposure and suggest that increased DA transporter densities may be a phenotypic marker of alcohol preference in vulnerable monkeys.

ISSN:0959-4965    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

We compared the cortical fields activated by simple, self-paced index-finger flexions with those activated during visually triggered movement and rest using PET. Of 12 fields detected during self-paced movement compared to rest, three were located in the classically defined motor areas: primary motor area (M1), premotor cortex (PM) and supplementary motor area (SMA). The latter extended into the cingulate motor area (CMA). Four corresponding clusters were also found when triggered movement was subtracted from self-paced movement. The change in regional cerebral blood flow (rCBF) was greater in SMA than in PM during self-paced movement compared with either control. We conclude that repetitive, self-paced index-finger flexions can activate SMA, PM and CMA, and that this movement activates SMA more strongly than PM.

ISSN:0959-4965    

出版商:OVID    

年代:1996

数据来源: OVID