摘要:

DIAZEPAM-BINDING inhibitor (DBI) and its processing products, including the octadecaneuropeptide (ODN), are polypeptides called endozepines which have multiple biological effects, including regulation of mitochondrial steroidogenesis and modulation of GABA-gated chloride channels. Concentrations of ODN-like immunoreactivity (ODN-Li) were measured by radioimmunoassay in the frontal cortex of nine drug-free suicides and nine drug-free sudden-death victims. The level of ODN-Li was higher in the right than in the left frontal cortex, in both suicide (p< 0.05) and control (p< 0.02) subjects. No significant differences were found between suicides and controls either in the right and left cortex, or when considering the gender and the post-mortem diagnosis of depression.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

THE role of repeated nicotine administration on sleep and major depression was studied. Six non-smoking normal volunteers (NV) and six non-smoking major depressed patients (MD) with a Hamilton Rating Scale for Depression > 18 served as subjects. All subjects underwent the following sleep procedures: acclimatization, control night, four nicotine nights (17.5 mg, transdermal patches) and one withdrawal night (WN). Nicotine increased REM sleep time in both groups and also on the WN. Hamilton scores showed an average reduction of 43.9% in the depressed patients. These findings suggest that nicotine receptor activation may be important in major depression and shows for the first time that nicotine patches may be useful in the treatment of depression.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

USING intracellular recordings in guinea pig brain slices, the pharmacology of electrophysiologically identified and immunohistochemically confirmed non-cholinergic nucleus basalis neurons was studied to determine their response to the major neurotransmitters of the subcortical afferents to this region. The cells were differentiated into three types: Type A cells (∼44%) were depolarized by noradrenaline (NA) and muscarine, Type B cells (∼23%) were depolarized by NA but hyperpolarized by muscarine, and Type C cells (∼15%) were hyperpolarized by both agonists. These cell types were also differentially responsive to serotonin (hyperpolarizing B, C) and histamine (depolarizing A, B). Accordingly, the non-cholinergic neurons share certain discharge properties but appear nonetheless to comprise distinct types which respond differentially to the major modulatory neurotransmitters and thus play potentially different roles in cortical modulation across the sleep–wake cycle.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Based on the results of recentin vitrostudies, tau has been proposed to be involved in regulating signal transduction through the phospholipase C-γ (PLC-γ) signaling pathway. The present study provides support for the physiological relevance of this hypothesis by demonstrating the existence of a tau-PLC-γ complexin situin a human neuroblastoma cell line. Both PLC-γ and PLC-δ, but not PLC-β, co-purified with microtubule-associated proteins. PLC-γ, but neither PLC-δ nor PLC-β, co-immunoprecipitated with tau, and the PLC co-precipitating with tau was enzymatically active. Additionally, both tau and MAP-2 co-precipitated with PLC-γ. These studies indicate that tau associates, either directly or indirectly, with PLC-γin situ, suggesting that tau may be appropriately localized to participate in the regulation of signal transduction through the PLC-γ pathwayin vivo.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The purpose of this study was to investigate the effects of acute and repeated electroconvulsive shock (ECS) on corticotropin releasing factor (CRF), proopiomelanocortin (POMC) and proenkephalin (PENK) gene expression in selected regions of the brain and pituitary of the rat. Acute ECS increased CRF gene expression in the paraventricular nucleus (PVN) by 20%, an effect that was further enhanced to 38% when rats received repeated ECS treatment. Acute and repeated ECS increased POMC gene expression in the arcuate nucleus (ARC) by 49–59% but failed to alter these mRNA levels in the anterior lobe (AL) of the pituitary gland. PENK gene expression was increased by 35% in the nucleus accumbens (NA) and by 180% the ventromedial nucleus (VMN) after acute or repeated ECS treatment but no significant changes were found in the PVN or striatum (ST). Taken together, these results indicate a differential CRF and opioid gene expression regulation after acute or repeated ECS treatment that may be relevant to their therapeutic or side effects in depression.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Although different mechanisms have been proposed, it has been suggested that apolipoprotein J (ApoJ) and metallothionein II (MTII), expressed by astrocytes, are protective proteins. Alterations in their expression may contribute to the involvement of astrocytes in epileptogenesis. We studied the expression of MTII and ApoJ genes 7 days following status epilepticus induced in rats by intra-amygdala injection of kainate (KA). ApoJ mRNA levels were increased in both cortex (77%,p< 0.01) and hippocampus (64%,p< 0.02), whereas, in contrast to previous findings 3 days after KA injection, DNA fragmentation was not detected on agarose gel electrophoresis. These results show that ApoJ is induced along with early genes during massive apoptosis, and remains induced after the acute phase. MTII mRNA levels were altered only in hippocampus (62%,p< 0.05), whereas KA-treated rats had no seizure for 7 days. The sustained induction of MTII mRNA shows that zinc homeostasis is not returned to normal or alternatively that astrocytes maintain an altered phenotype in spite of normal zinc release. Polyadenylated RNA and β-actin mRNA levels were in contrast unaltered in cortex or hippocampus at this time point. These specific variations in ApoJ and MTII mRNA expression during the latent period suggest that they are part of long term biochemical and/or phenotypic alterations in astrocytes, following a single episode of severe seizures.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

UNDER natural viewing conditions primates make frequent exploratory eye movements across complex scenes. We recorded neural activity of 62 cells in visual areas V1, V2 and V4 in an awake behaving monkey that freely viewed natural images. About half of the cells studied showed a modulation in firing rate following some of the eye movements made during free viewing, though the proportions showing a discernible modulation varied across areas. These cells were also examined under controlled viewing conditions in which gratings or natural image patches were flashed in and around the classical receptive field while the animal performed a fixation task. Activity rates were generally highest with flashed gratings and lowest during free viewing. Flashed natural image patches evoked responses between these two extremes, and the responses were higher when the patches were confined to the classical receptive field than when they extended into the non-classical surround. Thus the reduction of activity during free viewing relative to that obtained with flashed gratings is partly attributable to natural images being less effective stimuli and partly to suppressive spatio-temporal neural mechanisms that are important during natural vision.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

RECENT work has suggested that, in addition to spatial tonotopy, pitch and timbre information may be encoded in the temporal activity of the auditory cortex. Specifically, the post-stimulus latency of the maximal cortical evoked neuromagnetic field (M100 or N1m) is a function of stimulus frequency. We investigated the additional effect of varying the stimulus intensity on the M100 response. A 37-channel biomagnetometer recorded neuromagnetic fields over the temporal lobe of healthy volunteers in response to monaurally presented tones. The frequency dependence of the M100 latency remained remarkably invariant even at low stimulus intensity. Thus, for peri-threshold stimuli, frequency information appears encoded in the temporal form of the evoked response.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

TUMOUR necrosis factor-α (TNF-α) levels in mammalian brain increase during neuroinflammatory diseases. We used the competitive polymerase chain reaction (PCR) to quantify the amount of TNF-α in stimulated and unstimulated brain mast cells (BMC). A cDNA fragment shortened by a deletion of 56 bp was used as an internal TNF-α-specific standard. The immunological stimulus resulted in enhanced TNF-α mRNA expression and increased release of histamine and TNF-α. This is the first time that BMC showing functional FCϵRI-bound IgE receptors have been purified. Our results support the hypothesis that BMC mediators might induce an initial response in neuroinflammatory diseases.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

ACTIVATION of phospholipase C (PLC) in response to stimulation of δ-opioid, m4 muscarinic and α2 adrenergic receptors was observed in NG108-15 cells. Treatment with PLC specific inhibitors, U73122 and ET-18-OCH3, blocked δ-opioid receptor-mediated activation of G proteins with no effect on opioid binding to the receptors. U73122 treatment also suppressed functional responses of m4 muscarinic and α2 adrenergic receptors in NG108-15 cells. Furthermore, the G protein activation mediated by μ- and δ-opioid receptors and opioid receptor-like receptor (ORL1) were abolished by U73122 in SK-N-SH neuroblastoma cells. Inhibition of adenylyl cyclase induced by high concentrations of GTP was blocked by U73122, suggesting that blockade is at the level of G proteins. Our results thus indicated that inhibition of PLC leads to blockade of Gi protein activation mediated by opioid receptors or other Gi-coupled receptors.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID