ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Study of neurotransmitter role in food intake regulation in a leptin signaling deficient model, such as the Zucker rat, would benefit in the understanding of mechanisms of human obesity, in which leptin resistance is a common syndrome. We studied dopamine (DA) and serotonin (5-HT) concentrationsin vivoin the ventromedial nucleus (VMN) of the hypothalamus, as they relate to eating after food deprivation in obese and lean 9-week-old male Zucker rats. DA and 5-HT concentrations were measured by HPLC via microdialysis before and during refeeding in 24-h food-deprived rats. Before food was provided, mean baseline DA and 5-HT levels were lower in obese than in lean rats (9.2 ± 0.9vs15.1 ± 1.9 pg/10 μl,p< 0.01, and 0.68 ± 0.05vs1.17 ± 0.02 pg/10 μl,p< 0.001, respectively). Food intake was accompanied by a decrease in DA levels in both obese and lean rats to 64% (p< 0.01) and 65% (p< 0.02) of their baseline levels respectively. 5-HT levels were significantly increased during eating by 41% in obese and 35% in lean rats (p< 0.01) from the baseline levels. Thus in obese rats with altered leptin signaling we found an unaltered pattern of DA and 5-HT release associated with food deprivation and refeeding, but with presence of their low levels. This points to an impaired postsynaptic monoaminergic action to produce an adequate metabolic response in obese Zucker rats in response to feeding state.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The expression of the cyclin-dependent kinase inhibitor p21WAF1/CIP1mRNA after traumatic brain injury in rats was investigated using anin situhybridization technique, along with regulating gene p53 and stress response gene hsp70 mRNA levels. At 3h postinjury, p21WAF1/CIP1mRNA was markedly increased in the cortex, white matter, thalamus, CA2, a part of CA1,3 and dentate gyrus of the injured side. Hybridization signals remained elevated at 6 h in injured cortex and hippocampus and returned to the baseline by 24 h post-insult. On the other hand, p53 mRNA induction was not observed in any brain sections throughout the post-injury time course. Slight expression of hsp70 mRNA was detected in the injured cortex 3-6 h following injury and this was similar to the temporary pattern of p21WAF1/CIP1mRNA expression. This study showed p21WAF1/CIP1mRNA to be transiently induced after traumatic brain injury, independent of p53, this possibly being an early stress response to protect cells by arresting them in the cycle and allow DNA repair.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Recently, an Ile93Met substitution has been identified in the ubiquitin carboxy-terminal hydrolase L1 (UCHL1) gene in a single German PD family with autosomal dominant inheritance. To determine whether mutations in theUCHL1gene are causative for Parkinson's disease (PD) a detailed mutation analysis was performed in a large sample of German sporadic and familial PD patients. We found no disease-causing mutation in the coding region of theUCHL1gene. Direct sequencing revealed six intronic polymorphisms in theUCHL1gene. Analysis of an S18Y polymorphism in exon 3 of theUCHL1gene in sporadic PD patients and controls showed carriers of allele 2 (tyrosine) significantly less frequent in patients with a reduced risk of 0.57 (CI = 0.36–0.88;p= 0.012, pc = 0.047, χ2= 6.31). Our study shows that sequence variations in the coding region of UCHL1 are a rare event. A protective effect of a certain UCHL1 variant in the pathogenesis of sporadic PD is suggested, underlining the relevance of UCHL1 in neurodegeneration.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

N,N(Me)2-Dimethyl-tyrosine-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid-OH (N,N(Me)2-Dmt-Tic-OH) is a very selective δ opioid dipeptide with elevated antagonist activity. We have radiolabelled this compound by catalytic tritiation of the N,N(Me)2-Dmt(3',5′−12)-Tic-OH precursor. The ligand labelled rat brain membranes with a Kdvalue of 0.42 nM and a Bmaxof 63.12 fmol/mg protein. The new tritiated ligand showed high affinity for the δ opioid receptor whereas its binding at μ and κ opioid receptors was weak. N,N(Me)2-Dmt-Tic-OH was able to inhibit the agonist-stimulated binding of the non-hydrolysable GTP analogue [35S]GTPγS, thus attenuating the activation of G proteins via opioid receptors. This simple opioid dipeptide in both normal and labelled form may serve as a useful tool to study δ opioid receptorsin vitroandin vivo.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Perineuronal nets are extracellular structures enwrapping the soma and proximal dendrites of some neurons known to be parvalbumin immunoreactive. The composition of the nets is not completely known, but it can change between different neurons. We studied the heterogeneous composition of a specific component of perineuronal nets, the signaling molecule Janusin (or Tenascin R), by means of a double immunofluorescence using lectin fromWisteria floribundaas a general marker for perineuronal nets and an antibody against Janusin. The presence of two kinds of perineuronal nets, one rich in Janusin (the majority) and a second one devoid of this glycoprotein, indicates differential roles of these neurons, as well as differences in their afferents, or a difference in their functional state.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Studies in zebra finches failed to demonstrate the involvement of the NIf, a higher-order song nucleus afferent to the HVc, in the production of learned song. The song of the Bengalese finch, a related species, has a higher level of temporal organization; multiple song phrases are organized into a song. We hypothesized that the Nlf might control this complexity. To test this, we bilaterally lesioned the Nlf in adult male Bengalese finches. The songs of birds with multi-phrase organization changed into simpler, mono-phrase songs. This is the first demonstration of the Nlf's involvement in the production of birdsong. Zebra finch songs are syntactically simple and deterministic, and this might have caused the difficulty in demonstrating the function of the Nlf in zebra finches.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The chromosome 15q24 region, containing the CHRNA3/A5/B4 gene cluster, coding for the α3, α5 and β4 subunits of neuronal nicotinic acetylcholine receptors, has been reported to be linked to autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) in one family. However, nor the gene nor the mutation involved have been identified. We report the refined mapping of CHRNA3/A5/B4 cluster. Segregation analyses of CHRNA3/A5/B4 polymorphisms in families showing recombinations for 15q24 Généthon STR markers allowed to position the cluster in a 0.6 cM interval, between STRs D15S1027 and D15S1005. This location is external to the 15q24-ADNFLE-linked region, therefore excluding the involvement of this cluster in the pathogenesis of ADNFLE in the 15q24-linked family. Moreover, these data provide more precise information for further linkage studies.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

We investigated the contribution of ATP-sensitive potassium channels (KATP) and calcium-activated potassium channels (Kca2+) to cortical spreading depression (CSD)-associated hyperemia using the rat closed cranial window model. The peak CBF response was enhanced by 12 ± 5, 13 ± 4, and 28 ± 8% (p< 0.01) of the control with 10−6, 10−5and 10−4mol/l glibenclamide (glyb), a KATPantagonist, respectively. We also calculated the area under the CBF curve to fully represent the extent of hyperemia during CSD. The area increased by 30 ± 8 (p< 0.05), 72 ± 31 (p< 0.05) and 88 ± 20% (p< 0305) of the control with 10−6, 10−5and 10−4mol/l glyb, respectively. However, charybdotoxin (CTX), a Kca2+antagonist showed no effect. The effect of glyb was inhibited by pretreatment with 5 mg/kg indomethacin. We conclude that activation of KATP, perhaps associated with neurons, plays an inhibitory role in the CSD-associated hyperemia via an indomethacin-sensitive mechanism.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

We show here by whole field monitoring of free intracellular Ca2+([Ca2+]i), locally recorded field potential (fp) and external [Ca2+], that low-[Mg2+] induces seizure like events (SLEs) accompanied by simultaneous fluctuations of [Ca2+]iand [Ca2+]ein cultured hippocampal slices. Within a SLE, complex [Ca2+]efluctuations are seen throughout phases of Ca2+depletion (tonic) and Ca2+recovery (clonic) of the extra-cellular space. Information theory entropy-based analyses revealed strong asymmetric associations of [Ca2+]iand [Ca2+]ekinetics. By contrast, signal-associations between SLEs were found to be weak and of symmetric nature distinguishing seizure-like and interictal events by extensive coupling and decoupling of [Ca2+]iand [Ca2+]efluctuations, respectively.

ISSN:0959-4965    

出版商:OVID    

年代:2000

数据来源: OVID