摘要:

THE amygdala is a key structure in the brain's integration of emotional meaning with perception and experience.1Patients with depression have impaired functioning in emotional tasks involving the amygdala,2and have abnormal resting amygdala blood flow.3To better understand the anatomical basis for these functional changes we measured the volumes of the total amygdala and of the core amygdala nuclei in 20 patients with a history of depression and 20 pair-wise matched controls. Depressed subjects had bilaterally reduced amygdala core nuclei volumes and no significant differences in total amygdala volumes or in whole brain volumes. Since patients with a depression history have bilateral hippocampal volume reduction4the volume loss in this closely related structure suggests a shared effect on both structures, potentially glucocorticoid-induced neurotoxicity5mediated by the extensive reciprocal glutamatergic connections.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

A silent process involving both neural and vascular structures in diabetic retina persists for several years before clinically detectable retinopathy. Recordings of the electroretinogram (ERG) and visual evoked potential (VEP) provide early warning of abnormalities in the visual pathway of diabetic patients and animal models. Treatment of streptozotocin-diabetic rats for 1 or 2 months with the heat-shock protein coinducer bimoclomol, a drug ameliorating experimental neuropathy, prevented and corrected the abnormal increase in latency and reduction of amplitude of ERG and VEP waves both in acute and chronic experiments. Improvements may be explained by cytoprotective effect of bimoclomol on retinal glia and/or neurons against diabetes-related ischemic cell damages. These findings suggest that bimoclomol may have future therapeutic use in diabetic retinopathy.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

CO-LOCALIZATION of CCKBand D2receptor mRNAs was analysed in adjacent sections of nucleus caudate putamen of the rat by means ofin situhybridization. A distinct subpopulation of D2mRNA containing striatal nerve cells (in the order of 10%) was shown to co-express CCKBand D2receptor mRNAs. All the CCKBreceptor mRNA-positive nerve cells were co-localized with D2 receptor mRNA. These results give one morphological substrate to the previously demonstrated CCKB/D2receptor interactions in the striatum.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

GLUTAMATERGIC excitotoxicity has been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS). However, activation of metabotropic glutamate receptors (mGluRs) is neuroprotective in several paradigms. We therefore tested the effect of selective mGluR agonists on cultured chick embryonic motor neurons. Activation of group I mGluRs with (s)-3,5-dihydroxyphenylglycine (DHPG) and group III mGluRs with L-2-amino-4-phosphono-butanoate (L-AP4) promoted a modest but significant, dose-dependent delay of apoptosis, which could be blocked by specific mGluR antagonists. Group II or selective mGluR5 stimulations were ineffective. Correspondingly,in situhybridization experiments showed only expression of mGluR1 (group I) and mGluR4 and 7 (group III) in human motor neurons. Dissection of the pathways involved in this survival effect may help to elucidate the pathogenesis of ALS.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

CAPSAICIN has been suggested to act not only on thin primary afferents but also on the hypothalamus, but the neurotransmitter(s) of central capsaicin-sensitive neurons are unknown. The present study was conducted to determine whether any central, especially hypothalamic, glutamatergic terminals were sensitive to capsaicin. Capsaicin evoked glutamate release from slices of hypothalamus and lumbar dorsal horn, but not cerebellum. Such capsaicin action was Ca2+dependent and inhibited by the capsaicin antagonist capsazepine. Vanilloid receptor subtype 1 mRNA was widely distributed in the brain, with a marked level in the hypothalamus and cerebellum, but not in the spinal cord. The results suggest that there are glutamatergic terminals sensitive to capsaicin in the hypothalamus.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

EARLY-ONSET familial Alzheimer's disease (early-onset FAD) has been linked with mutations in the presenilin gene, PS1. Mutations in PS1 may affect the processing/ trafficking of β-amyloid precursor-protein (βAPP) and favour the production of toxic amyloid β-fragments that are associated with neural degeneration. This study reports the expression of a PS1-like cDNA in the carp (Cyprinus carpio) retina (the encoded protein shows 76% identity to the human PS1 protein). Carp PS1 mRNA was localized byin situhybridization to the photoreceptor cell, inner nuclear and ganglion cell layers. Expression of the PS1 gene in the rat retina was also confirmed. The retinal expression of PS1 raises the possibility that PS1 mutations also lead to neural degeneration in the retina.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

THE role of NMDA and non-NMDA receptors of the area postrema (AP) in the control of respiration and gastric motility was investigated in anaesthetized rabbits using microinjections (10–20 nl) of specific agonists or antagonists. NMDA (20 mM) or AMPA (10 mM) caused excitatory effects on respiration and gastric relaxation. Selective blockade of NMDA or non-NMDA receptors, respectively with D (–)-2-amino-5-phosphonopentanoic acid (D-AP5; 10 mM) and 6-nitro-7-sulphamoyl-benzo(f)quinoxaline-2,3-dione (NBQX; 5 mM), decreased respiratory frequency and increased gastric tone. Both these effects were more marked following non-NMDA receptor blockade and were prevented by vagotomy. These findings show that NMDA and non-NMDA receptors are present on AP neurones and have a role in the tonic control of respiration and gastric motility.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

THE anterior superior temporal polysensory area (STPa) has been hypothesized to be an integration site for signals coming from the dorsal and ventral visual pathways. To determine whether neurons in STPa were selective for simple two-dimensional geometrical shapes and whether this area might integrate different visual cues, cells were tested with motion-and luminance-defined shapes. Many neurons were activated by the shape stimuli under at least one condition; however, very few showed selectivity for a particular shape under either condition. Only one neuron responded selectively to shapes defined by both cues. Thus selectivity for simple shapes is not a prevalent property of STPa neurons and the integration of luminance and motion signals does not appear to occur at the single neuron level in STPa.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

THE expression of major histocompatibility complex (MHC) class I molecules on adult mouse Schwann cells (SCs) was examined using immunofluorescence analysis. MHC class I molecules were not expressed on the surface of untreated SCs. Interferon (IFN) γtreatment induced expression of the molecules on the SCs. Expression of genes coding for the molecules involved in MHC class I-mediated antigen presentation was also analysed in SCs by reverse transcription-polymerase chain reaction (RT-PCR). Expression of MHC class I heavy chain genes was faintly detected in untreated SCs. IFN γ treatment augmented the expression. In addition, IFN γ induced expression of the genes fo β2-microglobulin, the peptide transporter TAP-1 and the proteasomal subunit LMP-2, whose expression was not detected in untreated SCs. The expressions of MHC class II molecules and their genes were not detected even after IFN γ treatment. These data suggest that MHC class I-mediated antigen presentation machinery functions in adult mouse SCs and that the SCs themselves work as antigen presenting cells and as targets for cytotoxic T cells in some physiological conditions.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

FK506 is an immunosuppressive drug that binds to FK506 binding protein (FKBPs), a subgroup of cytosolic proteins called immunophillins. Previous works have revealed that FK506 protects neural cells from ischemia or excitotoxicity. Here we report that FK506 (10−6M) and not cyclosporine A (10−6M) blocks neuronal apoptosis induced by serum deprivation in rat neuronal cultures. In addition the immunohistochemical staining of C-jun protein in deprived cultures is markedly attenuated by FK506. The proportion of C-jun-positive neurons in control cultures, in serum-deprived cultures (48 h) and in serum-deprived cultures exposed to FK506 (10−6M) were 12.5%, 56.5% and 16.5%, respectively. The down-regulation of C-jun could play a major role in the anti-apoptotic action of FK506 in stressed neuronal cultures.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID