ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

We immunohistochemically examined the distribution of nerve fibers among supporting cells of the cochlea by using the bloc-surface preparation. The existence of these nerve fibers was not very clear in the standard avidin–biotin complex (ABC) method. However, the standard ABC method complemented with silver intensification procedure provided very fine details of the nerve fibers. The nerves started to appear at low density about 55% of the distance from the apex, and their density gradually increased toward the upper turn. In each portion, the nerve fibers increased in thickness and length as well as the number of synapses made with the nuclei. Moreover, the distribution of these nerves in the fetal cochlea was similar to that in the adult. However, the functional significance and importance of these nerves remains to be determined. Our study also indicates that the silver intensification procedure combined with the standard ABC method is useful for the detailed observation of stereoscopic innervation in thick tissue preparations like such as the cochlea.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Facial nerve lesions lead to a retrograde response characterized by activation of glia surrounding axotomized motoneurons and up-regulation of immunological cell surface molecules such as major histocompatibility complex (MHC) antigens. Cytokines, in particular interferon-&ggr;, are potent inducers of MHC expression and glial activation. We have here tested whether axotomy-induced activation is changed in transgenic mouse strains lacking components of the IFN-&ggr; signaling pathway, STAT4 or STAT6. No differences regarding astrocyte activation, ß2-microglobulin or MHC class I expression were discernible as compared to wild type controls. In contrast, there were conspicuous differences in the reaction between the examined wild type strains (C57BL/6J, BALB/c and 129/SvJ), suggesting considerable polymorphisms in the genetic regulation of these events, however, not involving IFN-&ggr;, STAT4 or STAT6.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Subjects were presented with terminal words that identified a sentence to reflect their true selves or another irrelevant individual. Subjects were asked to push one button if the statement reflected their true identity and another if it did not. The ERP to the terminal word consisted of a double-peaked positivity. Both the initial P300 (peaking between 300–350 ms) and a later P550 (peaking between 550 and 575 ms) were significantly larger to words that reflected the subject's true identity. When subjects were asked to take on a new identity, the P300 became larger to new, false words but the later P550 was large to both the false and the true words. The P550 to true identity words became smaller over a period of 3 days as subjects rehearsed their new roles. However, the P550 remained large to the false identity words although it was now attenuated relative to the true identity words. The late positivities may reflect a complex decisional process involving at least two stages. The initial stage might the initial yes–no decision. The later positivity may reflect the personal relevance of the terminal word. In this case, one's own true identity only begins to lose its relevance after time, and enacting the false identity then increases the positivity to this new identity.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

We used fMRI to study the human imitation of hand/arm postures and finger configuration, subjects imitated hand/arm postures in the hand condition, and they imitated finger configurations in the finger condition. Compared with the control condition, only the finger condition showed significant activation in Broca's area and symmetrical activation in the bilateral inferior parietal lobes, while the hand condition showed left lateralised superior parietal activation pattern. Our findings suggest that Broca's area might be involved more in the imitation of finger configuration than that of hand/arm postures. The result of parietal activation patterns was fully consistent with formerly reported clinical findings, and the relationship between the lesion laterality and the patients' perfomance of hand/finger action imitation.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The present study examined the sleep–wake cycle effects of microinjections of yohimbine, an adrenergic antagonist, and atropine, a cholinergic antagonist, into the cerebral ventricle of clomipramine-induced depressed rats. Yohimbine microinjection caused a significant reduction in the total duration and the number of REM sleep episodes compared to control saline injections. Atropine microinjection caused a significant reduction in the total duration and the number of REM sleep episodes without changing the REM sleep latency compared to control saline microinjection. These results show for the first time that the REM sleep disturbances observed in clomipramine-treatment induced depressed rats can be attenuated by increasing and decreasing the brain noradrenergic and cholinergic activities, respectively.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

New synapse formation may underlie learning and memory. To examine specific synaptic plasticity by motor learning, we conducted quantitative analysis of synapses between parallel fibers and Purkinje cell dendritic spines in cerebella of rats trained to complete various obstacle courses. Synapses between parallel fibers and Purkinje cell spines were classified into single synapse boutons, multiple synapse boutons, and multiple synapse spines by their different contact features. Acrobat-trained animals had more single and multiple synaptic boutons, without change of multiple synapse spines, than motor control animals. These results may suggest that motor learning induces specific synaptogenesis and Purkinje cell spines are primary sites in motor learning-dependent cerebellar synaptic plasticity.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The present study examined thein vivoeffects of ATP on the striatum of Sprague–Dawley rats. Intrastriatal administration of ATP produced dose-dependent striatal lesions as confirmed by cresyl violet staining. Additional immunostaining using neuronal nuclear protein (NeuN), OX-42 and GFAP antibodies revealed that ATP caused death of both neurons and glial cells. The nonmetabolizable ATP analogue ATP&ggr;S and P2X receptor agonist &agr;,&bgr;-methylene ATP (&agr;,&bgr;-MeATP) mimicked ATP effects, whereas either P2Y receptor agonist ADP or P1 receptor agonist adenosine did not. The P2 receptor antagonist reactive blue 2, but not pyridoxal-phosphate-6-azophenyl-2′,4′-disulphonic acid (PPADS) attenuated ATP-induced striatal injury. These results suggest that intrastriatal administration of ATP causes P2X receptor-mediated cell death in the striatum and support the hypothesis that extracellular ATP can be an important mediator of neuropathological events of brain injuries.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

We initially isolated CTL1 from the electric lobe ofTorpedobrain through functional complementation of a yeast mutant deficient in choline transport. Here, we present the first characterization of an antibody to the C-terminal ofTorpedoCTL1. When full length torpedo CTL1 was expressed in oocytes, a broad 60 kDa band appeared concomitant with the detection of immunoreactivity at the plasma membrane. InTorpedo, the native protein was prominent throughout the CNS and along the electric nerves. CTL1 immunolabeling was particularly conspicuous in the myelin sheath surrounding the electric nerve and in central myelinated structures. The association of the presumptive choline transporter, CTL1, with myelin membranes suggests a role for this new protein in lipid production.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The recent discovery of two mutations associated with autosomal dominant Parkinson's disease (PD) has led to the hypothesis that the &agr;-synuclein gene plays a role in the pathogenesis of PD. Here we report a novel triplet CAA repeat within the unusually large intron 5 sequence of the &agr;-synuclein gene. Microsatellite analysis revealed a high degree of polymorphism within the Irish population with seven alleles detected, ranging from eight to 17 CAA repeats. Analysis of the allele/genotype frequency differences observed between an Irish idiopathic PD cohort (n = 98) and a healthy aged control group (n = 92) revealed no strong association with either group. All PD subjects displaying homozygous profiles were examined for expansion of the trinucleotide repeat, but no expansion was observed. These results would suggest that polymorphism of the &agr;-synuclein gene may not play as significant a role in the pathogenesis of idiopathic PD as previously hypothesised.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID