摘要:

NEUROPEPTIDE Y (NPY) and endogenous opioids (EOPs) such as methionine-enkephalin (Met-enk) regulate similar physiological responses, but it is not known whether nociceptive and immune responses also show analogy after intracerebroventricular (i.c.v.) application. Dose–response studies show that Met-enk stimulates the blood granulocyte and splenic natural killer (NK) cell function of Lewis rats at a low dose (102ng/kg, i.c.v.), whereas a high dose (105ng/kg) causes suppression of innate immune functions associated with analgesia in the hot-plate test. At 15 min, 1 h and 24 h after i.c.v. application, both Met-enk (102ng/kg) and NPY (1 ng/kg) produced similar effects: An initial suppression of innate immune function was followed by a long lasting stimulatory action on cell functions and serum inter-leukin-6 (sIL-6) levels. Thus, central NPY application resembles Met-enk-induced immunostimulation at doses not affecting nociception, suggesting an involvement of both peptides in shaping stress-induced immunomodulation of the non-analgetic form, possibly via activation of a common immunomodulatory effector mechanism.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

FENAMATE compounds have been reported to inhibit ion channels in a number of tissues, including a non-selective cation channel in the mammalian outer hair cell (OHC). We have further investigated the effects of 3′-5-dichlorodiphenylamine-2-carboxylic acid (DCDPC) on OHC currents using the whole-cell configuration of the patch clamp technique. Extracellular application of 10μM DCDPC rapidly and reversibly activated an inward current at hyperpolarized potentials. The DCDPC-activated current appeared in the shorter OHCs from the basal turns of the cochlea. The reversal potential of the inward current was dependent on the external K+ion concentration. An outwardly rectifying K+ current, found predominantly in OHCs from apical turns, was reversibly inhibited by DCDPC. These results suggest that DCDPC has a significant effect on OHC physiology at all tonotopic locations along the basilar membrane and so may have implications for cochlear function during fenamate intake.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

GUINEA pigs received gentamicin to induce a profound hearing loss (61 dB auditory threshold shift at 18kHz). Concomitant administration of maleic or tartaric acid dissolved in dimethyl sulfoxide (DMSO) significantly reduced the threshold shift to< 40 dB. The results have several important implications. First, they support the hypothesis of a free-radical mechanism of gentamicin toxicity since the protective compounds are metal chelators and scavengers. Second, they caution against these and similar chemicals, commonly found in drug preparations, as vehicles in tests of aminoglycoside toxicity. For example, a recent study by others describing attenuation of aminoglycoside ototoxicity by NMDA antagonists may have been influenced by the presence of maleate, tartrate and DMSO. Third, they suggest simple antioxidants as a potentially efficient and inexpensive clinical prophylaxis of aminoglycoside-induced hearing loss.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

PSILOCYBIN, an indoleamine hallucinogen, produces a psychosis-like syndrome in humans that resembles first episodes of schizophrenia. In healthy human volunteers, the psychotomimetic effects of psilocybin were blocked dose-dependently by the serotonin-2A antagonist ketanserin or the atypical antipsychotic risperidone, but were increased by the dopamine antagonist and typical antipsychotic haloperidol. These data are consistent with animal studies and provide the first evidence in humans that psilocybin-induced psychosis is due to serotonin-2A receptor activation, independently of dopamine stimulation. Thus, serotonin-2A overactivity may be involved in the pathophysiology of schizophrenia and serotonin-2A antagonism may contribute to therapeutic effects of antipsychotics.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

THE endothelium is recognized as a major source of endothelin in the vasculature. In this report we show for the first time that endothelin can be demonstrated with immunoelectronmicroscopy in perivascular nerves. About 36% of the axon profiles (varicosity/intervaricosity) examined in the rat basilar artery showed immunolabelling with a polyclonal antibody to endothelin-1. Endothelin-labelled axon varicosities were characterized by the presence of small spherical agranular vesicles (42 ± 1 nm); some varicosities also contained large granular vesicles (++ ±5 nm) with labelled cores. Immunolabelling was mostly distributed in the axoplasm and in association with the membrane of synaptic vesicles (the lumen of the small agranular vesicles was immuno-negative). The presence of endothelin in perivascular nerves of the basilar artery suggests a neuronal as well as endothelial role in the physiological control of the vessel wall.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

THE roles of the basal ganglia and cerebellum in timing remain subject to debate. It has been suggested that temporal range may dissociate them, since cerebellar research has focused on intervals of < 1 s, compared with many seconds used in much basal ganglia research. Here we show increased but scalar variability of time estimates in patients with focal lesions of the lateral cerebellar cortex and nuclei when trained to remember durations in the seconds range, compared with patients with lesions of the mesial cerebellum and vermis. This distortion is discussed on the basis of previously reported cerebellar deficits in different time ranges and contrasted to distortions occurring in patients with basal ganglia lesions performing similar tasks over similar time ranges.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

THE activator protein-1 (AP-1) binding activities induced by a separate challenge with SKF38393 and quinpirole after 1 weeks’ abstinence from chronic methamphetamine (4 mg/kg/day, 14 days) were increased significantly in the striatum, nucleus accumbens and cingulate cortex compared with the saline-treated controls. Quinpirole-, but not SKF38393-induced AP-1 binding activities were still significantly higher after a 4-week abstinence period in the chronic methamphetamine group than in the chronic saline control group. Downward sniffing, which occurred following a quinpirole-challenge, was significantly intensified after both a 1 and 4 weeks’ abstinence from chronic methamphetamine. These results indicate that chronic administration of methamphetamine induces alterations of the interactions of dopamine D1 and D2 receptors which are reflected as enhanced AP-1 binding activities.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

THE odours of adult males, which accelerate the timing of puberty of female mice, activate c-fosin the accessory olfactory bulb (AOB). To test the hypothesis that NMDA receptors are involved in the male odour-induced increase in c-fosexpression, we studied the effects of the non-competitive NMDA receptor agonist MK-801 on male odour-induced c-fosexpression in the AOB of juvenile female mice. Surprisingly, MK-801 increased FOS-like immunoreactivity (FLI) within the AOB in the absence of male odour and had no effect on male odour-induced c-fosexpression. We suggest that MK-801 increases AOB mitral cell activity by disinhibiting GABAergic granule cells, resulting in increased c-fosexpression throughout the AOB.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

RECENTLY it has been reported that a missense G(88)C mutation within exon 3 and a missense G(209)A mutation within exon 4 of the α-synuclein gene were linked to familial Parkinson's Disease (PD). We decided to investigate if these and any other mutations in exons 3 and 4 of the α-synuclein gene could be detected in sixty two sporadic PD and dementia with Lewy bodies (DLB) patients. Four cases of familial DLB were also studied, two of which were from the same family. Single stranded conformational polymorphism, DNA sequencing analyses and PCR-RFLP of exons 3 and 4 failed to reveal any nucleotide changes. However, three nucleotide differences occurred in the intron 4 sequence compared to the published sequence. This study adds further support to the idea that these particular mutation in the a-synuclein gene are a rare case of PD and now, as we have shown here, also of DLB.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

HIGH-DENSITY EEG recordings revealed sensory specific modulation of anticipatory parieto-occipital ∼10 Hz oscillatory activity when visually presented word cues instructed subjects in an intermodal selective attention paradigm. Cueing attention to the auditory features of imminent compound audio-visual stimuli resulted in significantly higher ∼1 0 Hz amplitude in the period preceding onset of this stimulus than when attention was cued to the visual features. We propose that this parieto-occipital ∼1 0 Hz activity reflects a disengaged visual attentional system in preparation for anticipated auditory input that is attentionally more relevant. Conversely, lower ∼1 0 Hz activity during the attend—visual condition may reflect active engagement of parieto-occipital areas in the anticipatory period. These results support models implicating parieto-occipital areas in the directing and maintenance of visual attention.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID