ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Adult female rats sustained aspirative fimbria-fornix lesions and, 2 weeks later, received intrahippocampal grafts of fetal septal or mixed septal-raphe cell suspensions. Twenty-four months later, the extracellular concentration of hippocampal acetylcholine (ACh) was determined by microdialysis. Basal ACh levels (5–65 fmol/5 μl in sham-operated rats) were strongly reduced after lesioning (3–7 fmol/5 μl). In septally transplanted and septal-raphe co-transplanted rats, hippocampal ACh concentrations were restored to near-normal levels (15–25 fmol/5 μl), indicating long-term functional survival of hippocampal transplants. After administration of citalopram (100 μM by infusion) and fenfluramine (20 mg/kg i.p.), the hippocampal ACh efflux was increased by 2- to 3-fold in all groups of rats. The relative increase of ACh was highest in cotransplanted rats, an effect which was possibly due to functional interactions between grafted raphe and septal neurons.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Spinal cord injury (SCI) leads to an increase in extracellular excitatory amino acid (EAA) concentrations, resulting in glutamate receptor-mediated excitotoxicity and central sensitization. To test contributions of group I metabotropic glutamate receptors (mGluRs) in SCI induced release of glutamate and in behavioral outcomes of central sensitization following injury, we administered 1-aminoindan-1,5-dicarboxylic acid (AIDA; 0.1 nmol intraspinally), a potent group 1 mGluR antagonist, to rats immediately after spinal cord contusion injury. EAAs were collected by microdialysis and quantified using HPLC. AIDA significantly decreased extracellular glutamate but not aspartate concentrations and significantly attenuated the development of mechanical but not thermal allodynia. These results suggest mGluRs play an important role in injury-induced EAA release and in central sensitization following SCI.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Systemic administration of nitroglycerin, a nitric oxide donor, triggers in migraineurs a delayed attack of unknown mechanisms. Subcutaneous nitroglycerin (10 mg/kg) produced a significant increase of nitric oxide synthase (NOS)- and c-fos-immunoreactive neurons in the cervical part of trigeminal nucleus caudalis in rats after 4 h. This effect was not observed in the thoracic dorsal horn. Similar increase of NOS and c-fos was obtained in the brain stem after a somatic nociceptive stimulus, i.e. on the side of the formalin injection in the lip. Nitric oxide is thus able to increase NOS availability in second order nociceptive trigeminal neurons, which may be relevant for central sensitization and the understanding of its effect in migraine.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

We evaluated motor cortical excitability of the unaffected hemisphere in three patients with intractable epilepsy who underwent hemispherectomy, using transcranial magnetic stimulation (TMS) and PET. TMS of the unaffected hemisphere evoked motor responses not only in the contralateral muscles but also in the ipsilateral ones in all the patients. A PET study in one patient showed activation of the unaffected motor cortex by movement of either arm. All of these responses were enhanced after the hemispherectomy, probably due to motor cortical disinhibition by transection of the corpus callosum. The PET study also showed postoperative activation of the premotor area of the unaffected hemisphere. These phenomena indicate posthemispherectomy neuroplastic reorganization leading to preservation of the motor function after the operation.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

To identify cortical structures that subserve residual motor and sensory function in patients with congenital hemiparesis due to a porencephalic cyst, we examined, using [15O]H2O, PET and somatosensory evoked potentials (SEPs) in three patients with left-sided hemiparesis who had undergone hemispherectomy. Motor stimulation of the affected hand produced ipsilateral activation in the premotor area in all patients, the SMA in two patients, and SII in two patients. Vibrotactile stimulation resulted in activation of the ipsilateral SII in all subjects. Median nerve stimulation of the affected hand produced ipsilateral long-latency SEPs in fronto-centro-parietal areas, whereas stimulation of the non-affected hand produced normal early cortical potentials in the contralateral hemisphere. Our results suggest that residual function in the paretic hand is warranted through non-primary motor and sensory areas, and higher order associative areas in the intact hemisphere.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Presenilin I (PSI) has been shown to interact with microfilament-associated proteins of the filamin family. Here, we investigated a possible association of PSI with the cytoskeleton. Immunoblotting of detergent-insoluble fractions of rat brain homogenate revealed enrichment of neuron-specific 36 and 14 kDa proteolytic fragments of PSI, whereas 30 and 20 kDa fragments were found in the detergent-soluble fraction. Specific severing of microfilaments with gelsolin in the detergent- insoluble pellet and subsequent centrifugation led to the detection of both actin and PSI fragments in the supernatant. In addition, invitrotranslated PSI cosedimented with actin filaments. Our findings provide biochemical evidence for the association of PSI fragments with actin filaments.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Immunohistochemical techniques were employed to examine the distribution of RNA-binding proteins A2 and B1 in the rat forebrain. Intense A2 and B1 immunolabeling were observed in the nucleoplasm of the neurons in the cerebral cortices, hippocampal formation, olfactory regions, caudate-putamen as well as the supraoptic nucleus of hypothalamus. In contrast, within the bed nucleus of the stria terminalis, as well as the medial and lateral habenular nucleus of thalamus, immunoreactivity for both proteins was weak. Within the globus pallidus and thalamic nucleus immunoreactivity for A2 was hardly detectable despite of intense B1 immunolabeling, while within the endopiriform nucleus and lateral and basolateral nucleus of amygdala intensity of B1 immunolabeling was relatively weak compared to A2. Our study suggests that the distribution of A2 and B1 are not constant throughout the forebrain and this diversity may reflect the post-transcriptional regulation of cell-specific gene expression of neuronal cells.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Cerebellar granule neurons in primary culture underwent apoptosis when exposed to C2-ceramide. Addition of exogenous phosphatidylcholine (PtdCho) resulted in a dose-dependent full prevention of neuronal death. Exogenous PtdCho also prevented apoptosis induced by farnesol,N-oleoylethanolamine, and sphingomyelinase, but did not prevent apoptosis induced after lowering the potassium concentration in the medium to non-depolarizing levels. Moreover, C2-ceramide inhibited labeling of [32P]PtdCho in cells incubated with [32P]orthophosphate, with the same potency to that causing apoptosis. Although cell viability did not decrease during the first few hours, inhibition of PtdCho synthesis was already patent after a 1 h exposure to C2-ceramide. Taken together, these results strongly suggest that inhibition of PtdCho synthesis constitutes one of the primary events by which C2-ceramide triggers apoptosis in cerebellar granule neurons.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID