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991.
Jeffery D. Kocsis Mark N. Rand Karen L. Lankford Stephen G. Waxman 《Developmental neurobiology》1994,25(3):252-264
Cultured adult rat dorsal root ganglion (DRG) neurons were used to study depolarization-induced Ca2+ mobilization and the effects of intracellular Ca2+ depletion on neurite outgrowth. Cytoplasmic and nuclear Ca2+ signals were visualized in dissociated DRG neurons using confocal scanning laser microspcopy and the Ca2+ indicator dye fluo-3. The depolarization-induced Ca2+ signals were highest in neurons during the first few days in culture, prior to neurite extension; during this time nuclear signals exceeded those of the cytoplasm severalfold. After several days in culture, neurons began to arborize, depolarization-induced Ca2+ signals became attenuated, and nuclear signals no longer exceeded those of the cytoplasm. Elevated Ca2+ signals were dependent upon both Ca2+ influx and intact intracellular Ca2+ stores, indicating that the signals are generated by calcuim-induced calcium release (CICR). Thapsigargin, an endoplasmic reticulum Ca2+ ATPase inhibitor, depleted intracellular Ca2+ stores and blocked the induction of the large nuclear Ca2+ signals. Treating DRG neurons briefly with thapsigargin (200 nM for 20 min) shortly after plating reduced subsequent neuritogenesis, impyling that intact Ca2+ stores are necessery for initiating neurite outgrowth. Immunostaining of DRG neurons with antibodies to Ca2+ /calmodulin-dependent kinase II (CaM kinase II) demonstrated that this enzyme is present in the nucleus at early times in culture. These observations are consistent with the idea that CICR triggered by Ca2+ entry subsequent to depolarization may elicit neurite outgrowth by activating nuclear enzymes appropriate for such outgrowth. © 1994 John Wile & Sons, Inc. 相似文献
992.
In zebrafish, apart from mononuclear melanophores, bi‐ and trinuclear melanophores are frequently observed; however, the manner in which multinucleation of these cells occurs during fish development remains unknown. Here, we analyzed the processes underlying multinucleation of zebrafish melanophores. Transgenic zebrafish in which melanophore nuclei were labeled with a histone H2B‐red fluorescent reporter protein were used to evaluate the distribution of mono‐, bi‐, and trinuclear melanophores in both the trunk and fin. Half of the melanophores examined were binuclear and approximately 1% were trinuclear. We compared cell size, cell motility, and survival rate between mono‐ and binuclear melanophores grown in a culture dish, and we found that cell size and survival rate were significantly larger in binuclear melanophores. We then analyzed the behavior of melanoblasts and melanophores from transgenic zebrafish using in vivo and in vitro live‐cell imaging. We detected division and differentiation of melanoblasts, as well as melanoblast nuclear division without subsequent cellular division. In addition, we observed cellular and nuclear division in melanophores, although these events were very infrequent in vitro. On the basis of our findings, we present a scheme for melanophore multinucleation in zebrafish. 相似文献
993.
Validated multi‐step approach for in vivo recording and analysis of optogenetically evoked glutamate in the mouse globus pallidus 下载免费PDF全文
Thomas Viereckel Åsa Konradsson‐Geuken Åsa Wallén‐Mackenzie 《Journal of neurochemistry》2018,145(2):125-138
994.
995.
Interaction of CacyBP/SIP with NPM1 and its influence on NPM1 localization and function in oxidative stress 下载免费PDF全文
Calcyclin (S100A6) binding protein/Siah‐1 interacting protein (CacyBP/SIP) is mainly a cytoplasmic protein; however, some literature data suggested its presence in the nucleus. In this work we examined more precisely the nuclear localization and function of CacyBP/SIP. By applying mass spectrometry, we have identified several nuclear proteins, among them is nucleophosmin (NPM1), that may interact with CacyBP/SIP. Subsequent assays revealed that CacyBP/SIP forms complexes with NPM1 in the cell and that the interaction between these two proteins is direct. Interestingly, although CacyBP/SIP exhibits phosphatase activity, we have found that its overexpression favors phosphorylation of NPM1 on S125. In turn, the RNA immunoprecipitation assay indicated that the altered CacyBP/SIP level has an impact on the amount of 28S and 18S rRNA bound to NPM1. The overexpression of CacyBP/SIP resulted in a significant increase in the binding of 28S and 18S rRNA to NPM1, whereas silencing of CacyBP/SIP expression decreased 28S rRNA binding and had no effect on the binding of 18S rRNA. Further studies have shown that under oxidative stress, CacyBP/SIP overexpression alters NPM1 distribution in cell nuclei. In addition, staining for a nucleolar marker, fibrillarin, revealed that CacyBP/SIP is indispensable for maintaining the nucleolar structure. These results are in agreement with data obtained by western blot analysis, which show that upon oxidative stress the NPM1 level decreases but that CacyBP/SIP overexpression counteracts the effect of stress. Altogether, our results show for the first time that CacyBP/SIP binds to and affects the properties of a nuclear protein, NPM1, and that it is indispensable for preserving the structure of nucleoli under oxidative stress. 相似文献
996.
Rats were infused intraventricularly with [3H]tyrosine over a 20-min period during various times while circling. 3,4-Dihydroxyphenylethylamine (dopamine) and dihydroxyphenylacetic acid (DOPAC) levels were measured using HPLC with electrochemical detection and fractions were collected for tritium monitoring. During the first 20 min of circling, the specific activity of dopamine was increased by 290% in striatum contralateral to the circling direction whereas DOPAC specific activity was increased 50% on the same side. This differential change in relative specific activity suggests that unlabeled storage pool dopamine was mobilized to DOPAC during circling. Synthesis of dopamine and DOPAC in contralateral striatum returned to baseline levels as turning slowed (50-70 min). When turning ceased, there was an increase in ipsilateral striatal dopamine synthesis during the 20-min period following circling. We hypothesize that this ipsilateral increase represents either a "stop" signal following circling or a release of inhibition of ipsilateral nigral neurons. 相似文献
997.
998.
Summary Ultrastructural post-embedding immuno-gold techniques were applied to the supraoptic nucleus and the neurohypophysis of mice and rats. The primary antibodies were three different monoclonal antineurophysins, used in protein A-gold and immunoglobulin-gold procedures. Conventional plastic embedding as well as hydrophilic media (L.R. White) were used; non-osmicated and osmicated tissues were immunolabeled; sodium metaperiodate oxidation was used, but was not essential for immunolabeling.Vasopressinergic and oxytocinergic NSGs were identified by the specific immunoreactivity of their respective neurophysins on adjacent thin sections, and by sequential double labeling on the same thin section using two different antibodies associated with gold probes of different diameters. The immunoidentification indicates that vasopressin NSGs can additionally be differentiated as larger, with more electron-dense matrix, and susceptible to damage by sodium metaperiodate.The only organelles consistently labeled were neurosecretory granules (NSGs), either intact or within lysosomal configurations. Some lysosomal dense bodies were immunoreactive even when discrete NSGs were no longer morphologically recognisable within them. Labeled NSGs were located within neuronal cell bodies, along axonal shafts and within axonal swellings and endings; occasionally immunoreactive NSGs were observed within synaptic boutons. Labeling intensity was semi-quantitatively gauged by counting gold particles in relation to numbers of NSGs per axonal varicosity.The precise localisation achieved with particulate immunogold labeling surpasses that previously obtained with diffuse electron-dense immunoreaction products. 相似文献
999.
Hiroshi Yao Takashi Matsumoto Makoto Hirano Toshihide Kuroki Tetsuyuki Tsutsumi Hideyuki Uchimura Kaoru Nakamura Tatsuo Nakahara Masatoshi Fujishima 《Neurochemical research》1989,14(1):75-79
This study attempted to investigate the possible involvement of the brain stem noradrenergic system in the development of hypertension in spontaneously hypertensive rats. Steady-state norepinephrine, dopamine, serotonin and 5-hydroxyindoleacetic acid concentrations and norepinephrine turnover were determined in the individual brain stem nuclei using high performance liquid chromatography with electrochemical detection. Decreased norepinephrine contents in the nucleus tractus solitarii in spontaneously hypertensive rats compared with Wistar-Kyoto rats at the age of 4, 8, and 16 weeks were demonstrated. In later stages (8 and 16 weeks), increased norepinephrine levels were observed in the nucleus reticularis gigantocellularis, the A1 and A5 areas. Norepinephrine turnover was not different between spontaneously hypertensive rats and Wistar-Kyoto rats in the nucleus tractus solitarii at the age of 4 and 16 weeks and increased in the nucleus reticularis gigantocellularis of spontaneously hypertensive rats at 16 weeks. Our results indicate that altered norepinephrine metabolism in the specific brain stem nuclei, especially the consistently decreased norepinephrine in the nucleus tractus solitarii of spontaneously hypertensive rats, contribute to the development of genetic hypertension. 相似文献
1000.
Rintaro Sugita Yutaka Sawa Soichiro Nomura Stevin H. Zorn Tadamitsu Yamauchi 《Neurochemical research》1989,14(3):267-270
The effect of reserpine (2 mg/kg i.p.) on both locomotor activity and the turnover of dopamine metabolite in the rat nucleus accumbens was estimated by using an activity monitor (Animex) and by in vivo brain microdialysis. Three to five hours after reserpine administration locomotor activity was reduced and there was a concomitant increase in the level of the dopamine metabolite, homovamillic acid. These findings suggest that depletion of dopamine from the nucleus accumbens may result in decreased locomotor activity. The data support the notion that dopamine in this tissue contributes to the control of locomotion. 相似文献