ISSN:0959-4965    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Fetal cerebellar cell suspensions, prepared from wild-type (+/+) mice, were implanted bilaterally into the cerebellum of Purkinje cell degeneration' (pcd) mutant mice, a model of adult-onset recessively inherited cerebellar ataxia, to study the functional effects of the grafts on motor coordination and fatigue resistance in a rotating rod treadmill paradigm. The viability of transplanted Purkinje cells was verified with immunocytochemistry for calbindin-D28kand for glutamate receptor 2/3 subunits and within situhybridisation histochemistry for insulin-like growth factor I mRNA, biochemical markers normally expressed by Purkinje cells in the cerebellum. Sham injections of vehicle did not appreciably modify the performance ofpcdmutants in the rota-rod tests. On the other hand, bilateral cerebellar grafts led to a 3.5-fold increase in the time period that recipientpcdmice were able to stay on the rotating drum based on the comparison of mean scores (of three trials) or a 5.5-fold increase based on the comparison of maximum scores (of the three trials). These findings provide evidence for a motor enhancement in thepcdmouse model of hereditary cerebellar ataxia following intracerebellar transplantation of primordial Purkinje cells.

ISSN:0959-4965    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

The effect of intraventricular fetal mesencephalic grafts placed in the previously 6-hydroxydopamine (6-OHDA) lesioned striatum on the kinetics of [3H]dopamine (DA) uptake into striatal synaptosomes prepared from the non-lesioned (contralateral) striatum was studied in rats. Using WIN 35,065 as specific [3H]DA uptake inhibitor, the equilibrium dissociation constant (Km) of [3H]DA uptake into synaptosomes of the non-lesioned (contralateral) striatum did not differ between grafted and non-grafted controls 7 months after grafting. However, the maximal rate of specific [3H]DA uptake (Vmax) was markedly decreased in the non-lesioned striatum of grafted animals. This result indicates that fetal mesencephalic grafts reduce the [3H]DA uptake in the non-lesioned (contralateral) striatum by reducing the number of functional DA transporters.

ISSN:0959-4965    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Inositol phospholipid-specific phospholipase C (PLC) generates two important second messengers, inositol triphosphate and diacylglycerol. The recently cloned rat PLCβ4 cDNA is highly homologous to the norpA cDNA ofDrosophila melanogaster. We have mapped the PLCβ4 gene expression in rat brain tissue sections byin situhybridization. The PLCβ4 gene is expressed at high abundance in cerebellar Purkinje cells and neurones of the substantia nigra, the median geniculate bodies and the thalamic nuclei. PLCβ4 transcripts are also detected in the mammillary nuclei, the neocortex, the habenula and the olfactory bulbs. The specific pattern of gene expression we have observed should help to clarify the relationships between the PLCβ4 and various constituents of second-messenger systems involved in transduction mechanisms triggered by the stimulation of seven transmembrane domain receptors. The strong gene expression in Purkinje cells and retinal neurones suggests that PLCβ4 may be involved in the pathogenesis of mouse and human neurological diseases characterized by ataxia and retinal degeneration.

ISSN:0959-4965    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Nitric oxide (NO), a free radical gas that acts as a neural messenger, is produced from l-arginine by the enzyme nitric oxide synthase (NOS). The present study describes the autoradiographic localization throughout rat brain of the binding of [3H]l-NG-nitro-arginine ([3H]l-NOARG), a reversible NOS inhibitor, and confirms the heterogeneous distribution of the NOS enzyme. [3H]l-NOARG binding was enriched in discrete neuronal populations and the distribution observed was identical to that previously described for NOS using immunohistochemistry,in situhybridization and NADPH-diaphorase staining. [3H]l-NOARG autoradiography should be a useful method for the further characterization and quantification of NOS in brain and other tissues.

ISSN:0959-4965    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

The prefrontal cortex (PFC) receives dopaminergic (DA) afferents from the ventral tegmental area (VTA) and excitatory inputs from the hippocampal formation. The present electrophysiological experiments performed in anaesthetized rats demonstrate that activation of the mesocortical DA system blocked the spontaneous activity of PFC neurones and the excitatory responses induced by hippocampal stimulation. These data indicate that there is a convergence in the effects of hippocampal and DA mesocortical afferents on common PFC neurones. Furthermore, a population of PFC neurones responding to hippocampal stimulation could be identified as projecting to either the nucleus accumbens and/or the VTA, suggesting that the hippocampus exerts an indirect influence on these two structures through the PFC.

ISSN:0959-4965    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

In order to test the putative interaction between galanin and the vasodilatatory basalocortical cholinergic system, anaesthetized ventilated rats received a microinjection into the substantia innominata of 0.9% NaCl, 50 nmol carbachol, 50 nmol carbachol and 200 ng galanin, or 200 ng galanin. Cerebral blood flow (CBF) was measured with [14C]iodoantipyrine by the tissue sampling technique immediately following the intracerebral infusions. Under coinjection conditions, the flow increases observed after carbachol microinjection in the ipsilateral temporal and frontoparietal cortices were found to be significantly reduced (−37%,p≤ 0.02 and −25%,p≤ 0.05 respectively) compared with carbachol stimulated rats. The infusion of galanin by itself had no effect on CBF. These results demonstrate that galanin inhibits the vasodilatatory basalocortical cholinergic system an thus may possibly influence CBF by indirect mechanisms.

ISSN:0959-4965    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Converging evidence points to hypofunction of the left prefrontal cortex in depression. Repetitive transcranial magnetic stimulation (rTMS) activates neurons near the surface of the brain. We questioned whether daily left prefrontal rTMS might improve mood in depressed subjects and report a pilot study of such treatment in six highly medication-resistant depressed inpatients. Depression scores significantly improved for the group as a whole (Hamilton Depression Scores decreased from 23.8 ± 4.2 (s.d.) at baseline to 17.5 ± 8.4 after treatment; t = 3.03, 5DF,p= 0.02, two-tailed pairedt-test). Two subjects showed robust mood improvement which occurred progressively over the course of several weeks. In one subject, depression symptoms completely remitted for the first time in 3 years. Daily left prefrontal rTMS appears to be safe, well tolerated and may alleviate depression.

ISSN:0959-4965    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

The injury associated with implantation of an inert gelatin matrix (gel foam) into normal mouse striatum induces a long-lived increase in binding of [3H]mazindol to presynaptic dopamine uptake sites, probably due to proliferation of striatal dopaminergic terminals. Because of the known effects of leukaemia inhibitory factor (LIF) on catecholaminergic cells, we tested the hypothesis that LIF may alter the striatal dopaminergic response to injuryin vivo. Application of LIF to mouse striatum in a gel foam implant abolished the usual injury induced proliferation of dopamine uptake sites. The ability of LIF to prevent proliferation of dopamine terminals may have important implications for our understanding of neural regeneration, the aetiology of Parkinson's disease and its treatment by intrastriatal grafting.

ISSN:0959-4965    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Spatial attention during visual search was examined in 14 persons with mild Alzheimer's disease (AD) and 28 healthy older subjects, 14 aged 65–74 (young-old), and 14 aged 75–85 (old-old). Subjects searched for single feature (color) or conjunction (color + letter) targets in displays of 10 or 15 letters. Precues of differing sizes were used to provide localizing information of varying precision. Effects of display size and cue size on reaction time (RT) for color search were similar in AD subjects and controls. For color + letter search, however, AD patients showed minimal effects of cue size, pointing to an impairment in AD in the spatial focusing of attention during visual search. Pathology affecting the association parietal and extrastriate areas may mediate impairment of spatial attention and visual search in AD.

ISSN:0959-4965    

出版商:OVID    

年代:1995

数据来源: OVID