摘要:

We examined the timing of apoptosis and the expression of the DNA repair proteins poly(ADP-ribose) polymerase (PARP) and Ku80 in sections of frontal and temporal lobes from patients who had suffered severe brain ischaemia due to a cardiac arrent.In situ endlabelling(ISEL) was used to detect apoptotic cells, and immunohistochemistry to assess PARP and Ku80. ISEL of scattered neurons and glia was demonstrable predominantly during the first 24 h after ischaemia. PARP and Ku80 immunoreactivity increased markedly after cerebral ischaemia, PARP particularly in the regions of greatest susceptibility to hypoxic injury: the CA1 field of the hippocampus and the depths of noecortical sulci. The up-regulation of PARP is in keeping with experimental observations concerning the key role of this enzyme in mediating ischaemic cell death.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant muscular dystrophy characterized by late onset ptosis, proximal muscle weakness and swallowing difficulties. This disease has been recently linked to chromosome 14q11.2-q13 in French-Canadian pedigrees. We studied three unrelated American families with OPMD of Hispanic descent and our results indicate that in this ethnic group, this disease also maps to chromosome 14q11.2-q13 (marker MYH7.24; Zmax= 3.98; &thetas;max= 0). These results represent an independent demonstration of disease linkage in a second distinct ethnic group. Furthermore, our analysis demonstrates a unique haplotype that is shared by affected individuals from all three families suggesting a founder effect for OPMD in this population. Meiotic recombinants and radiation hybrid mapping permit the narrowing of the critical region to 1 Mb which will facilitate positional cloning of the OPMD disease gene.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

It has been suggested that hyperexcitability in dorsal root ganglion (DRG) neurons due to altered sodium channel expression contributes to some chronic pain syndromes. To understand the role of the voltage-gated sodium channel α-SNS in inflammatory pain, we investigated the expression of α-SNS mRNA and tetrodotoxin-resistant (TTX-R) sodium current in small DRG neurons, which include nociceptive cells, following injection of carrageenan into the hind paw of the rat usingin situhybridization and patch-clamp recording. α-SNS mRNA expression in DRG neurons projecting to the inflamed limb was significantly increased 4 days following carrageenan injection, compared with DRG neurons from the contralateral side or naive (uninjected) rats (mean ± s.d. optical density ratio: ipsilateral/contralateral, 1.77 ± 0.17; ipsilateral/naive, 1.88 ± 0.36). The amplitude of the TTX-R sodium current in small DRG neurons projecting to the inflamed limb was significantly larger than on the contralateral side 4 days post-injection (31.7 ± 3.3vs20.0 ± 2.1 nA). The TTX-R current density was also significantly increased. These results demonstrate the increased expression of α-SNS sodium channels in small DRG neurons following injection of carrageenan into their projection field, and suggest that α-SNS is involved in the development of hyperexcitability associated with inflammation.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Using whole-cell patch-clamp techniques, we show that oligosphere-derived oligodendrocyte progenitor cells (OP) display GABA-, glutamate-, 5-HT-, glycine- and acetylcholine-gated inward currents. When OP differentiate into oligodendrocytes (ODC), the amplitude of peak currents elicited by saturating concentrations of these transmitters decreases except for 5-HT. Intracellular Ca2+concentration changes induced by microperfusion of glutamate, 5-HT, TRH, met-enkephalin and substance P were monitored using a fluo-3-based calcium imaging system. When OP cells differentiate into ODC, a global decrease of the proportion of responding cells is observed. During type-2 astrocytes commitment, this proportion decreases for 5-HT, TRH- and metenkephalin stimulations whereas it remains constant for substance P and glutamate. These data demonstrate a development regulation of neurotransmitter- and neuropeptide-induced responses within the oligodendroglial lineage.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Genetic susceptibility plays an important role in the development of schizophrenic psychoses, and the neural maldevelopment hypothesis is suggested by neuropathological and neuroimaging findings. We investigated the association between a null mutation in the ciliary neurotrophic factor (CNTF) gene and functional psychoses including schizophrenia and schizoaffective disorder. The frequency of mutant allele was significantly increased in patients with schizoaffective disorder, but not in those with schizophrenia in comparison with controls. TheCNTFnull mutation resulting in CNTF deficiency may confer potential susceptibility to schizoaffective disorder.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

(S)-4-Carboxy-3-Hydroxy-Phenylglycine [(S)-4C3HPG] is a potent competitive antagonist at the metabotropic glutamate receptor 1 subtype (mGlu1 receptor) and an agonist at mGlu2/3 receptor. We evaluated histologically the effect of this compound on transient global ischaemia in gerbils and observed pronounced neuroprotection in the CA1 layer of the hippocampus. When (S)-4C3HPG (1 μM) was administered intra-cerebroventricularly (i.c.v.) 20 min before clamping both common carotid arteries neuronal density was comparable with that in sham-operated animals. A single injection (1 μM) 65 min after ischaemia also significantly reduced neuronal damage. The results suggest that metabotropic glutamate receptors play a role in the deleterious cascade which leads to neuronal damage of pyramidal cells in the CA1 layer of the hippocampus after transient global ischaemia.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

This study examined the directional modulation of dorsal premotor (PMd) cells as a function of time in an instructed delay, reaching task that systematically varied direction and accuracy constraints. In two monkeys, the activity of 150 PMd cells was recorded and the preferred direction (PD) of the firing as a function of time, the PD trajectory, was calculated. Forty-one cells had nearly continuous significant directional tuning of at least 1 s duration (mean duration 1694 ± 754 ms) that began in the instructed delay period and continued into the movement period. The PD gradually changed in time (mean change of 47.7 ± 40.8°), a change best described as a rotation. The change in the directional tuning as a function of time is consistent with the hypothesis that the PMd plays a role in the non-standard mapping of sensory stimuli into motor commands.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Conditioned fear stimuli suppress motor activity. The fear stimuli suppress vasopressin and facilitate oxytocin and prolactin release. These fear responses are impaired by selective destruction of noradrenergic neurones. Adenosine 5′-triphosphate is co-released from noradrenergic nerve terminals with noradrenaline. Thus the possibility arises that the behavioural and neuroendocrine responses may be mediated by purinergic rather than noradrenergic synapses. We examined whether suramin, an inhibitor of P2 and NMDA receptors, blocks conditioned fear responses. Suramin injected i.c.v. 30 min before testing stimuli impaired conditioned fear responses. The role of purinergic P2 receptors in expression of the behavioural and neuroendocrine responses to conditioned fear stimuli is discussed.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Neural retinas of the golden hamster (Mesocricetus auratus) express circadian rhythms of melatonin synthesis when cultured in constant darkness. Retinas from wild-type hamsters synthesize melatonin with a period close to 24 h, while retinas obtained from hamsters homozygous for the circadian mutationtau, which shortens the free-running period of the circadian activity rhythm by 4 h, synthesize melatonin with a period close to 20 h. The retinal circadian oscillators of both wild-type andtaumutant hamsters are temperature compensated; however, temperature compensation is adversely affected by the mutation.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Functional reorganization of auditory attention was studied in 12 congenitally blind subjects and 12 controls using high-density event-related potentials during a highly focused dichotic listening task. Reaction times for the attend-ear intensity-deviant targets were markedly faster for the blind. Brain activity associated with sustained attention (N1 effect, Nd), and with the automatic detection of deviants in an unattended channel (MMN), did not exhibit reorganization. In contrast, marked plasticity changes were reflected in late auditory attentional processing (attend-ear targets), in the form of a prolonged negativity (200–450 ms post-stimulus) that was absent in the sighted subjects. The plasticity changes in the blind had a time course indicating progressive recruitment of parietal and then occipital regions, providing new evidence for cross-modal sensory reorganization in the blind.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID