大鼠大脑皮质星形胶质细胞条件培养液促进小脑皮质神经元的生长

本研究从大鼠大脑皮质分离、纯化星形胶质细胞,再经培养后收集星形胶质细胞的无血清条件培养液。用盖玻片培养法与快速自动比色微量分析法研究了星形胶质细胞条件培养液对小脑皮质神经元生存以及神经元活力的影响。发现星形胶质细胞条件培养液能够明显提高小脑皮质神经元的体外存活率,增强神经元的活力。表明星形胶质细胞具有神经营养性作用。     

Immunochemical Characterization of Pyruvate Dehydrogenase Complex in Rat Brain

Pyruvate dehydrogenase complex (PDHC) in rat brain was studied immunochemically, using antibodies against the bovine kidney PDHC, by immunoblotting, immunoprecipitation, inhibition of enzyme activity, and enzyme-linked immunoabsorbent assay (ELISA). The immunoblots showed that the antibodies bound strongly to the alpha peptide of the pyruvate dehydrogenase (E1) component, and to the dihydrolipoyl transacetylase (E2) and the dihydrolipoyl dehydrogenase (E3) components of PDHC. A similar immunoblotting pattern was observed in all eight brain regions examined. On immunoblotting of the subcellular fractions, these PDHC peptides were observed in mitochondria and synaptosomes but not in the postmitochondrial supernatants. This agrees with other evidence that brain PDHC is localized in the mitochondria. These results, together with those from sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the immunoprecipitin, also showed that the alpha E1, beta E1, and E3 peptides of rat brain PDHC are very similar in sizes to those of the bovine kidney PDHC, being 42, 36, and 58 kD, respectively. The size of the E2 peptide, 66 kD, is different from that of bovine kidney E2, 73 kD. The relative abundance of PDHC protein in nonsynaptic mitochondria was compared by enzyme activity titration and ELISA. Both methods demonstrated that the amount of PDHC antigen in the mitochondria from cerebral cortex is greater than that in the olfactory bulb mitochondria. This is consistent with the results of the activity measurement. The ELISA also showed that the PDHCs in both mitochondrial populations are antigenically similar.(ABSTRACT TRUNCATED AT 250 WORDS)     

升温诱发高血压大鼠脑梗塞发病的神经内分泌机制

目的：研究气温骤升导致高血压大鼠发生脑梗塞的神经内分泌机制。方法：采用易卒中型肾血管性高血压（RHRSP）模型,放置于人工模拟气温骤升的高温环境中诱发脑梗塞,检测高温刺激前后大鼠ACTH、CORT、TSH、T3、T4的变化。结果：突然升温使生理组大鼠ACTH和CORT水平表现升高的趋势。模型组高血压大鼠CORT、TSH、T3、T4水平在升温中均呈现升高趋势,但是ACTH水平却明显降低（P〈0.05）。升温后发生脑梗塞大鼠的ACTH和T4水平与升温前比明显下降（P〈0.01）,而TSH水平明显高于升温前水平（P〈0.05）,T3水平不变。结论：高血压机体应激反应系统紊乱,甲状腺刺激素和肾上腺皮质激素的异常波动,是突然高温促发高血压机体脑梗塞发病的重要神经内分泌机制。     

Right-hemispheric dominance for visual remapping in humans

We review evidence showing a right-hemispheric dominance for visuo-spatial processing and representation in humans. Accordingly, visual disorganization symptoms (intuitively related to remapping impairments) are observed in both neglect and constructional apraxia. More specifically, we review findings from the intervening saccade paradigm in humans--and present additional original data--which suggest a specific role of the asymmetrical network at the temporo-parietal junction (TPJ) in the right hemisphere in visual remapping: following damage to the right dorsal posterior parietal cortex (PPC) as well as part of the corpus callosum connecting the PPC to the frontal lobes, patient OK in a double-step saccadic task exhibited an impairment when the second saccade had to be directed rightward. This singular and lateralized deficit cannot result solely from the patient's cortical lesion and, therefore, we propose that it is due to his callosal lesion that may specifically interrupt the interhemispheric transfer of information necessary to execute accurate rightward saccades towards a remapped target location. This suggests a specialized right-hemispheric network for visuo-spatial remapping that subsequently transfers target location information to downstream planning regions, which are symmetrically organized.     

Localization of choline acetyltransferase in laminae of the rat olfactory tubercle

Abstract: We report the distribution of choline acetyltransferase (ChAT) activity in the laminae of the rat olfactory tubercle. Within its posterior medial portion, the tubercle contains three parallel histological laminae that can be separated by cutting tangential sections from frozen tissue. ChAT was measured in homogenates of consecutive sections (16 μm) cut parallel to these laminae. The distribution of ChAT activity, as a function of tubercle depth, showed a broad peak centered at 500 μm from the ventral surface of the brain. Enzyme activity measured at this depth (85 pmol acetylcholine formed/μg protein/h) was 2 1/2 times greater than that measured in the outermost, plexiform, layer. Stereotaxic injections of kainic acid (1 μg in 1 μ1) made directly into the tubercle were used to eliminate intrinsic neurons. Three days after injection, histological examination revealed the almost total absence of neuronal cell bodies and the proliferation of glial cells. The greatest decreases in ChAT activity (50%) were seen at depths of 300–600 μm whereas no loss of activity occurred in the plexiform layer.     

Regulation of gap junction coupling in the developing neocortex

In the developing mammalian, neocortex gap junctions represent a transient, metabolic, and electrical communication system. These gap junctions may play a crucial role during the formation and refinement of neocortical synaptic circuitries. This article focuses on two major points. First, the influence of gap junctions on electrotonic cell properties will be considered. Both the time-course and the amplitude of synaptic potentials depend,inter alia, on the integration capabilities of the postsynaptic neurons. These capabilities are, to a considerable extent, determined by the electrotonic characteristics of the postsynaptic cell. As a consequence, the efficacy of chemical synaptic inputs may be crucially affected by the presence of gap junctions. The second major topic is the regulation of gap junctional communication by neurotransmitters via second messenger pathways. The monoaminergic neuromodulators dopamine, nordrenaline, and serotonin reduce gap junction coupling via activation of two different intracellular signaling cascades—the cAMP/protein kinase A pathway and the IP₃/Ca²⁺/protein kinase C pathway, 013 respectively. In addition, gap junctional communication seems to be modulated by the nitric oxide (NO)/cGMP system. Since NO production can be stimulated by glutamate-induced calcium influx, the NO/cGMP-dependent modulation of gap junctions might represent a functional link between developing glutamatergic synaptic transmission and the gap junctional network. Thus, it might be of particular importance in view of a role of gap junctions during the process of circuit formation.     

The amygdala and ventromedial prefrontal cortex: functional contributions and dysfunction in psychopathy

The current paper examines the functional contributions of the amygdala and ventromedial prefrontal cortex (vmPFC) and the evidence that the functioning of these systems is compromised in individuals with psychopathy. The amygdala is critical for the formation of stimulus-reinforcement associations, both punishment and reward based, and the processing of emotional expressions. vmPFC is critical for the representation of reinforcement expectancies and, owing to this, decision making. Neuropsychological and neuroimaging data from individuals with psychopathy are examined. It is concluded that these critical functions of the amygdala and vmPFC, and their interaction, are compromised in individuals with the disorder. It is argued that these impairments lead to the development of psychopathy.