摘要:

RATS were deprived of sleep for 96 h by the platform technique and total glutathione (GSHτ) levels were measured in seven different brain areas. Glutathione levels were found to be significantly reduced in the hypothalamus of sleep-deprived animals when compared with large platform (−18%) or home cage (−31%) controls. Deprived rats also had reduced GSHπ levels in thalamus compared with home cage controls only. Glutathione levels did not differ among the three groups in any of the other brain areas examined. These results indicate that specific brain areas may be differentially susceptible to oxidative stress after sleep deprivation. The apparent vulnerability of the hypothalamus to these effects may contribute to the functional effects of sleep deprivation.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

BOTH adenosine A1and A2receptor populations are located in the striatum and can modify locomotor activity, and they may form a therapeutic target for Parkinson's disease (PD). Administration of the selective adenosine A2Aantagonist (E)-1,3-diethyl-8-(3,4-dimethoxystyryl)-7-methyl-3,7-dihydro-1H-purine-2,6-dione (KW-6002) to MPTP-treated common marmosets increased locomotor activity. In contrast, administration of the selective A1receptor antagonist 1,3-dipro-pyl-8-cyclopentylxantine (DPCPX) had no effect on locomotion. Administration of the adenosine A2Areceptor agonist 2-[p-[2-(2-aminoethylamino) carbonylethyl] phenethyl amino]-5'-N-ethylcarboxamidoadenosine (APEC) dose dependently suppressed basal locomotor activity. A minimally effective dose of APEC (0.62 mg/kg, i.p) completely reversed the increase in locomotor activity produced by administration of KW-6002. The adenosine A2Areceptor appears to be an important target for the treatment of basal ganglia disorders, particularly PD.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

CATECHOL-O-METHYLTRANSFERASE (COMT, EC 2.1.1.6) is a ubiquitous enzyme crucial to catechol metabolism. Two isoforms exist in the human central nervous system (CNS) and they are encoded by two transcripts(1.3 and 1.5 kb) in most human tissues. Using two α-32P-labeled probes, we found only the 1.5 kb transcript in all 16 regions of the human CNS using commercially available Northern blots. Spinal cord had the highest and amygdala had the lowest levels of expression. The other CNS regions shared a similar level of expression. The distributions of COMT gene expression relative to whole brain between both probes were significantly correlated. Our study shows that the expression of the 1.5 kb transcript is crucial for COMT activity in all regions of the human CNS.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

DURING tactile exploration cells in human somatosensory cortex S-I receive input from skin receptors and from proprioceptive feedback. To study the extent to which these sources contribute to cell activation we used functional magnetic resonance imaging (fMRI) in order to visualize the spatial extent and amplitude of activation in S-I during active finger movement and passive stimulation of finger tips. In all subjects (n=6) we measured activation elicited by unilateral single finger tapping (active task) and mechanical stimulation of the palm of the index finger (passive task). In the finger tapping condition all subjects showed a strict contralateral activation of somatosensory cortex S-I and motor cortex M-I. In the passive stimulation experiment we found activation of the contralateral somatosensory cortex S-I only. Although subjects were trained to perform the finger movement with the same frequency and pressure in comparison to the passive stimulation, the activation within S-I induced by finger movements was always significantly larger than that induced by passive stimulation. This result implies that activation of somatosensory cortex originates to a large extent from proprioception while tactile input plays a minor role in S-I excitation

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

THE nuclear factor-kappa B (NFkB) and the signal transducer activator of transcription 3 (STAT3), are putative transcription factors activated by growth factors and cytokines, and involved in glial gene expression changes after neuronal injury. Immunocyto-chemical analysis of NFκB and STAT3 from 2 h to 14 days after excitotoxic damage to the postnatal rat brain showed STAT3-and NFkB-positive glial cells at 2 h post-lesion, increasing in number to reach a maximum at day 1. Immunoreactivity then decreased but the glial scar remained positive. Glial STAT3 immunoreactivity was located in the nucleus up to 1 day post-lesion and in the nucleus, cytoplasm and cell processes from day 3. Glial NFκB immunoreactivity was mainly cytoplasmatic.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

A strong synergistic interaction between the bicuculline-sensitive GABA receptor (GABAAreceptor) and the strychnine-sensitive glycine receptor was observed in third-order neurons acutely isolated from crucian carp retina, with the use of the whole-cell patch-clamp recording technique. In 58 of 153 cells, 10 μM GABA or glycine separately applied to amacrine/ganglion cells failed to induce any responses or only induced small currents (< 20 pA), while co-application of these two chemicals resulted in much larger responses (403.05 ± 319.98 pA). The current induced by the co-application was mediated by chloride channels, and both GABAAand glycine receptors were involved in the potentiation. The underlying mechanisms of this interaction and its possible physiological role are discussed.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

SYSTEMIC administration of 3-nitropropionic acid (3NPA) in rats produces bilateral striatal lesions which are similar to those seen in Huntington's disease (HD). We examined the effects of systemic 3NPA on the expression of cytochrome oxidase (COX-II and COX-IV), succinate dehydrogenase (SDH) and astrocytic glial fibrillary acidic protein (GFAP) mRNAs and on the activity of COX and SDH as assessed by the density of histochemical staining. COX-II and COX-IV mRNA was reduced in rats with 3NPA-induced lesions, but not in those without, whereas SDH, but not COX, staining was significantly and dose-dependently reduced in both 3NPA treated groups. GFAP mRNA expression was increased in both intact striatum and cortex but was absent from the lesion core

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

THE conditioned place preference (CPP) induced by cocaine 2.5mg/kg was measured in rats pre-exposed to ethanol (14 days with only 10% v/v ethanol followed by a free choice between ethanol solution and water for 14 days). Rats were divided according to their alcohol intake during the free choice period into low-drinking (< 3 g/kg per day), intermediate-drinking and high-drinking (> 4 g/kg per day) rats. Cocaine-induced CPP was not modified in high-drinking rats relative to controls. Low-drinking rats had a lower CPP than high-drinking rats and controls. We conclude that pre-exposure to alcohol did not sensitize to the cocaine rewarding effects, and that alcohol low-drinking rats showed the lowest preference for cocaine.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

IMMUNOCYTOCHEMISTRY was used to identify glial cell line-derived neurotrophic factor (GDNF) in rat spinal cord. Strong GDNF labeling was found in fibers and terminals in laminae I and II (outer) and to a lesser extent in the remaining laminae. A few spinal ganglion cells also contained GDNF. After dorsal root transection GDNF disappeared from the dorsal horn and after dorsal root ligation there was accumulation of GDNF only on the ganglion side of the ligation. These findings demonstrate anterograde transport of GDNF within primary afferent fibers, which constitute the only source of GDNF labeling in the dorsal horn. The strong presence of GDNF in the superficial dorsal horn may indicate that GDNF has a role in pain transmission in the adult rat spinal cord.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

TO investigate the sites of nitric oxide synthase (NOS) expression after a spinal cord (SC) injury, NADPH-d diaphorase histochemistry was performed in the SC of adult rats sacrificed at different times from 1h to 90 days after both SC contusion or transection. NOS could first be seen 12h after injury in axonal swellings (AS) (club shaped structures at the tip of damage axons, associated with tissue destruction). NOS expression reached a maximum 3 days after injury, and gradually disappeared after 7 days. Finally, AS collapsed leaving behind micro-cysts. NOS expression and the consequent production of nitric oxide could be involved in the pathophysiology of the secondary damage, and/or could reflect a failed attempt for axonal regeneration

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID