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1.
We examined the expression of the KCC2 isoform of the K‐Cl cotransporter in the developing and adult brain, using an affinity‐purified antibody directed against a unique region of the KCC2 protein. Expression was shown to be limited to neurons at the cell bodies and cell processes in the hippocampus and cerebellum. Expression seemed to be the highest at the end of processes that originated from the CA1 pyramidal cells. Developmental up‐regulation of KCC2 expression was demonstrated in the entire rat brain by Northern and Western blot analyses, and in the hippocampus by immunofluorescence. Level of KCC2 expression was minimal at birth and increased significantly during postnatal development. This pattern of expression was opposite to the one of the Na‐K‐2Cl cotransporter that is highly expressed in immature brain and decreases during development. The up‐regulation of the K‐Cl cotransporter expression is consistent with the developmental down‐regulation of the intracellular Cl− concentration in neurons. The level of intracellular Cl−, in turn, determines the excitatory versus inhibitory response of the neurotransmitter γ‐aminobutyric acid in the immature versus mature brain. Finally, KCC2 expression was shown in dorsal root ganglion neurons, demonstrating that expression of the cotransporter is not strictly confined to central nervous system neurons. © 1999 John Wiley & Sons, Inc. J Neurobiol 39: 558–568, 1999 相似文献
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Schliess F Schäfer C vom Dahl S Fischer R Lordnejad MR Häussinger D 《Archives of biochemistry and biophysics》2002,401(2):187-197
The expression of sodium potassium chloride cotransporter 1 (NKCC1) was studied in different liver cell types. NKCC1 was found in rat liver parenchymal and sinusoidal endothelial cells and in human HuH-7 hepatoma cells. NKCC1 expression in rat hepatic stellate cells increased during culture-induced transformation in the myofibroblast-like phenotype. NKCC1 inhibition by bumetanide increased alpha(1)-smooth muscle actin expression in 2-day-cultured hepatic stellate cells but was without effect on basal and platelet-derived-growth-factor-induced proliferation of the 14-day-old cells. In perfused rat liver the NKCC1 made a major contribution to volume-regulatory K(+) uptake induced by hyperosmolarity. Long-term hyperosmotic treatment of HuH-7 cells by elevation of extracellular NaCl or raffinose concentration but not hyperosmotic urea or mannitol profoundly induced NKCC1 mRNA and protein expression. This was antagonized by the compatible organic osmolytes betaine or taurine. The data suggest a role of NKCC1 in stellate cell transformation, hepatic volume regulation, and long-term adaption to dehydrating conditions. 相似文献
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We examined the ability of SV40-immortalized human and rabbit corneal epithelial cells (HCEC and RCEC, respectively) to adapt
to chronic hypertonic stress. Under isotonic conditions, in the presence of 50 μm bumetanide, proliferation measured as 3H-thymidine incorporation declined in RCEC and HCEC by 8 and 35%, respectively. After 48 hr exposure to 375 mOsm medium, RCEC
proliferation fell by 19% whereas in HCEC it declined by 45%. Light scattering behavior demonstrated that both cell lines
mediate nearly complete regulatory volume increase (RVI) responses to an acute hypertonic (375 mOsm) challenge, which in part
depend on bumetanide-sensitive Na-K-2Cl cotransporter (NKCC) activity. Following exposing RCEC for 48 hr to 375 mOsm medium,
their RVI response to an acute hypertonic challenge was inhibited by 17%. However, in HCEC this response declined by 68%.
During exposure to 375 mOsm medium for up to 24 hr, only RCEC upregulated NKCC gene and protein expression as well as bumetanide-sensitive
86Rb influx. These increases are consistent with the smaller declines in RVI and proliferation capacity occurring during this
period in RCEC than in HCEC. Therefore, adaptation by RCEC to chronic hypertonic stress is dependent on stimulation of NKCC
gene and protein expression and functional activity. On the other hand, under isotonic conditions, HCEC RVI and proliferation
are more dependent on NKCC activity than they are in RCEC.
Received: 7 March 2000/Revised: 18 May 2000 相似文献
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Wu-Gang Hou Yong Zhao Lan Shen Jie Zhao Xue-Wu Liu Zhen Li Xin-Ping Liu Li-Bo Yao Yuan-Qiang Zhang 《Cell and tissue research》2009,337(2):257-267
N-Myc downstream regulated gene 2 (NDRG2) is expressed in the testis of adult animals and is involved in cell differentiation
and development. However, little is known about the expression pattern of NDRG2 in the testis during postnatal development.
Here, we show that NDRG2 is consistently expressed in Leydig cells in the rat testis during postnatal development. However,
its expression has also been detected at a high frequency in spermatogenic cells of the seminiferous tubules in young rats
but at a much lower frequency in adult rats. Furthermore, high levels of NDRG2 expression have been found in methoxyacetic-acid-induced
apoptotic germ cells, particularly at stages X–XIII of the seminiferous epithelium cycle of adult rats. Interestingly, high
levels of NDRG2 expression have also been observed in spontaneously apoptotic germ cells in the seminiferous tubules of young
and adult rats. Thus, the expression of NDRG2 in germ cells seems to alter during spermatogenesis. These findings suggest
that NDRG2 regulates testicular development and spermatogenesis in rats and is involved in the physiological and pathological
apoptosis of germ cells.
Wu-Gang Hou, Yong Zhao, and Lan Shen contributed equally to this study.
This study was supported by the Natural Science Foundation of China (2006: no. 30600340; 2007: no. 30771138; 2008: no. 30871309). 相似文献
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Akiyama K Miyashita T Mori T Mori N 《Biochemical and biophysical research communications》2007,364(4):913-917
The endolymphatic sac (ES) is a part of the membranous labyrinth that contains the cochlea, vestibular organs, and semicircular canals, and is believed to absorb endolymphatic fluid. Na+–K+–2Cl− (NKCC) is a cotransporter that occurs as two isoforms (NKCC-1 and NKCC-2). Especially, NKCC-2 is suggested to participate in ES endolymph absorption. In the present study, the expression and cellular localization of NKCC-1 and NKCC-2 in the rat ES were examined by RT-PCR and in situ hybridization, respectively. The findings indicate that both NKCC-1 and NKCC-2 are expressed in the rat ES and suggest that NKCC is involved in ES homeostasis. NKCC-2 may be particularly involved in endolymph absorption. This is the first report confirming NKCC expression in the ES. 相似文献
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1. Aim of the present paper is to study the expression of N-Methyl-D-Aspartate receptor (NMDAR) subunits NR2A and NR2B within mouse visual cortex.2. To investigate the influence of neurotrophic factor of NGF family (neurotrophins) on NMDAR expression we used mutant mice carrying a deletion in the gene for brain-derived neurotrophic factor (BDNF), a well-known neurotrophin expressed in visual cortex.3. Western blot and immunohistochemistry were performed at postnatal day P12–14, P21–23, and adulthood showing that both subunits change during postnatal development.4. Absence of BDNF induced a reduction of NR2A level. This effect was specific since the other subunit investigated, NR2B, was not affected in mutant mice.5. We conclude that endogenous BDNF modulates NMDAR expression in the developing visual cortex. 相似文献
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Tümpel S Cambronero F Ferretti E Blasi F Wiedemann LM Krumlauf R 《Developmental biology》2007,302(2):646-660
The Hoxa2 gene is an important component of regulatory events during hindbrain segmentation and head development in vertebrates. In this study we have used sequenced comparisons of the Hoxa2 locus from 12 vertebrate species in combination with detailed regulatory analyses in mouse and chicken embryos to characterize the mechanistic basis for the regulation of Hoxa2 in rhombomere (r) 4. A highly conserved region in the Hoxa2 intron functions as an r4 enhancer. In vitro binding studies demonstrate that within the conserved region three bipartite Hox/Pbx binding sites (PH1-PH3) in combination with a single binding site for Pbx-Prep/Meis (PM) heterodimers co-operate to regulate enhancer activity in r4. Mutational analysis reveals that these sites are required for activity of the enhancer, suggesting that the r4 enhancer from Hoxa2 functions in vivo as a Hox-response module in combination with the Hox cofactors, Pbx and Prep/Meis. Furthermore, this r4 enhancer is capable of mediating a response to ectopic HOXB1 expression in the hindbrain. These findings reveal that Hoxa2 is a target gene of Hoxb1 and permit us to develop a gene regulatory network for r4, whereby Hoxa2, along with Hoxb1, Hoxb2 and Hoxa1, is integrated into a series of auto- and cross-regulatory loops between Hox genes. These data highlight the important role played by direct cross-talk between Hox genes in regulating hindbrain patterning. 相似文献
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Dopaminergic agents ameliorate experimentally induced gastroduodenal mucosal injury, but there is no information about their effect on small intestinal mucosa. We studied the effect of L-dopa and related substances on indomethacin-induced intestinal ulceration in the rat. Ulceration was produced by s.c. injection of 30 mg/kg indomethacin, 30 min after refeeding fasted rats. Total ulcer area was measured 24 hrs after indomethacin administration. L-dopa, 5 mg/kg given in two divided doses 5 h apart, starting 30 minutes before administration of indomethacin, was found to protect the small bowel mucosa against indomethacin- induced damage (ulcer area 122 +/- 5.5 vs 224.2 +/- 5.4 mm2, mean +/- SEM, p less than 0.006). Administration of 5 mg/kg haloperidol, a dopa antagonist, did not abolish the protective effect of L-dopa. On the other hand, yohimbine, an alpha-2-adrenoreceptor antagonist, almost completely abolished the protective effect (180.4 +/- 5.3 vs 122 +/- 5.5, p less than 0.004). Clonidine 20 micrograms/kg, an alpha-2-adrenoreceptor agonist, closely mimicked the protective effect of L-dopa (141.5 +/- 10.9 vs 224.2 +/- 5.4, p less than 0.006). All drugs were give i.p. in two divided doses, at the same schedule as described for L-dopa. The results demonstrate that L-dopa has a protective effect on indomethacin-induced small bowel injury in the rat. The protective effect is probably mediated through stimulation of alpha-2-adrenoreceptors. 相似文献
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Bribián A Esteban PF Clemente D Soussi-Yanicostas N Thomas JL Zalc B de Castro F 《Developmental neurobiology》2008,68(13):1503-1516
At embryonic stages of development, oligodendrocyte precursors (OPCs) generated in the preoptic area colonize the entire optic nerve (ON). Different factors controlling migration of ON OPCs have been identified, including secreted growth factors, morphogens and guidance cues, as well as cell adhesion molecules. We have shown previously that the soluble form of the extracellular matrix (ECM) protein anosmin-1, impairs OPC migration induced by FGF-2. In the present work, we show that anosmin-1 is expressed by both migrating OPCs and axons of the retinal ganglion cells in the embryonic ON. In vitro, we observe that OPC migration is strongly impaired by contact with anosmin-1 when used as a substrate and, in contrast to previous results, this effect is independent of FGF-2/FGFR1 signaling. We also show that OPCs preferentially adhere to anosmin-1 when compared with other ECM molecules used as substrates, and that when the endogenous anosmin-1 expressed by OPCs is blocked, OPC adhesion to all the different substrates (including anosmin-1), is significantly reduced. This novel effect of anosmin-1 on cell adhesion is also independent of FGF-2/FGFR1. We finally demonstrate that the blockade of the endogenous anosmin-1 expressed by OPCs impairs their migration. Our data suggest that the endogenous anosmin-1 expressed by OPCs is necessary for the correct adhesion of these cells to the different components of the ECM (including anosmin-1 itself), contributing to the migration of these cells. 相似文献
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Kristina Kosenburger Klaus W. Schicker Helmut Drobny Stefan Boehm 《Journal of neurochemistry》2009,110(6):1977-1988
Through inhibitory and excitatory effects on sympathetic neurons, B2 bradykinin receptors contribute to protective and noxious cardiovascular mechanisms. Presynaptic inhibition of sympathetic transmitter release involves an inhibition of CaV 2 channels, neuronal excitation an inhibition of KV 7 channels. To investigate which of these mechanisms prevail over time, the respective currents were determined. The inhibition of Ca2+ currents by bradykinin reached a maximum of 50%, started to fade within the first minute, and became attenuated significantly after ≥ 4 min. The inhibition of K+ currents reached a maximum of 85%, started to fade after > 3 min, and became attenuated significantly after ≥ 7 min. Blocking Ca2+ -independent protein kinase C (PKC) enhanced the inhibition of Ca2+ currents by bradykinin and delayed its fading, left the inhibition of K+ currents and its fading unaltered, and enhanced the reduction of noradrenaline release and slowed its fading. Conversely, direct activation of PKC abolished the inhibition of noradrenaline release and largely attenuated the inhibition of Ca2+ currents. These results show that the inhibitory effects of bradykinin in sympathetic neurons are outweighed over time by its excitatory actions because of more rapid, PKC-dependent fading of the inhibitory response. 相似文献
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Expression of P2X receptors on immune cells in the rat liver during postnatal development 总被引:1,自引:0,他引:1
Xiang Z Lv J Jiang P Chen C Jiang B Burnstock G 《Histochemistry and cell biology》2006,126(4):453-463
Single and double-labeling immunofluorescence and RT-PCR expression of P2X receptor proteins and mRNAs were used in a study of the liver of postnatal rats. OX62 and ED1 were used as markers for dendritic and macrophage (Kupffer) cells respectively. The results showed that the P2X6 receptor subunit was up-regulated by 15-fold on hepatic sinusoid cells during postnatal days P1 to P60. Subpopulations of Kupffer cells co-expressed P2X4 and P2X6 receptor subunits and dendritic cells co-expressed P2X4 and P2X7 receptor subunits. Lipopolysaccharide (endotoxin) injected into the peritoneal cavity led to increased expression of the P2X6 receptor on Kupffer cells, suggesting that the P2X6 receptor subunit may be up-regulated by endotoxin. This study presents the first evidence that P2X receptors are widely distributed in the rat liver immune system and that activation of Kupffer and dendritic cells in the rat liver might be regulated by extracellular ATP. 相似文献
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《Peptides》2014
This study was conducted to determine the mechanisms by which serotonin (5-hydroxytryptamine, 5-HT) receptors are involved in the suppression of food intake in a rat stress model and to observe the degree of activation in the areas of the brain involved in feeding. In the stress model, male Sprague–Dawley rats (8 weeks old) were given intracerebroventricular injections of urocortin (UCN) 1. To determine the role of the 5-HT2c receptor (5-HT2cR) in the decreased food intake in UCN1-treated rats, specific 5-HT2cR or 5-HT2b receptor (5-HT2bR) antagonists were administered. Food intake was markedly reduced in UCN1-injected rats compared with phosphate buffered saline treated control rats. Intraperitoneal administration of a 5-HT2cR antagonist, but not a 5-HT2bR antagonist, significantly inhibited the decreased food intake. To assess the involvement of neural activation, we tracked the expression of c-fos mRNA as a neuronal activation marker. Expression of the c-fos mRNA in the arcuate nucleus, ventromedial hypothalamic nucleus (VMH) and rostral ventrolateral medulla (RVLM) in UNC1-injected rats showed significantly higher expression than in the PBS-injected rats. Increased c-fos mRNA was also observed in the paraventricular nucleus (PVN), the nucleus of the solitary tract (NTS), and the amygdala (AMG) after injection of UCN1. Increased 5-HT2cR protein expression was also observed in several areas. However, increased coexpression of 5-HT2cR and c-fos was observed in the PVN, VMH, NTS, RVLM and AMG. Whereas, pro-opiomelanocortin mRNA expression was not changed. In an UNC1-induced stress model, 5-HT2cR expression and activation was found in brain areas involved in feeding control. 相似文献
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Expression of the Ca(2+)-dependent phospholipids binding protein annexin A2 (ANX2) in the brain is thought to be largely associated with brain pathological conditions such as tumor, inflammation, and neurodegeneration. The recent findings that ANX2 heterotetramer is involved in learning and neuronal activities necessitates a systematic investigation of the physiological expression of ANX2 in the brain. With combination of in situ hybridization and immunohistochemistry, ANX2 mRNA and protein were specifically detected in a group of GABAergic interneurons throughout the brain. Although ANX2 was absent from the interior of pyramidal neurons, it was found on the membrane and seemly the extracellular space of those neurons, where they closely co-localized with glutamate decarboxylase terminals. In cultured developing neurons, ANX2 was present at high concentrations in the growth cones co-distributing with several growth-associated proteins such as growth associated protein 43 (GAP43), turned on after division/Ulip/CRMP (TUC-4), tubulin, and tissue-plasminogen activator. It then became predominantly distributed on the membrane and mostly in axonal branches as neurons grew and extended synaptic networks. ANX2 was also secreted from cultured neurons, in a membrane-bound form that was Ca(2+)-dependent, which was significantly increased by neuronal depolarization. These results may have implications in the function and regulatory mechanism of ANX2 in the normal brain. 相似文献
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Expression of VEGFR-2 on HaCaT cells is regulated by VEGF and plays an active role in mediating VEGF induced effects 总被引:4,自引:0,他引:4
Yang XH Man XY Cai SQ Yao YG Bu ZY Zheng M 《Biochemical and biophysical research communications》2006,349(1):31-38
Vascular endothelial growth factor (VEGF) and its receptor VEGFR-2 play important roles in mitogenesis and chemotaxis of endothelial cells. In normal human skin, VEGF is expressed and secreted by epidermal keratinocytes. Emerging data suggest that keratinocyte-derived VEGF targets other cell types besides the dermal endothelial cells. We have recently showed that keratinocytes from human normal skin expressed all five known VEGF receptors and co-receptors (neuropilin 1 and 2). To define the functional significance of VEGFR-2 in epidermis, we examined its role in a keratinocyte cell line, HaCaT cells, in response to VEGF treatment. Expression of VEGFR-2 on HaCaT cells was confirmed at both RNA and protein levels and was regulated by VEGF165 treatment. Treatment of HaCaT cells with VEGF165 induced tyrosine-autophosphorylation of VEGFR-2 and phosphorylation of PLC-gamma and p44/42 MAPK in a time-dependent manner. Preincubation with a neutralizing antibody for VEGFR-2 (MAB3571) completely abrogated these phosphorylation effects. Furthermore, VEGF165 stimulated proliferation and migration of HaCaT cells, and this effect was significantly blocked by a pretreatment with MAB3571. Neutralizing VEGFR-2 in HaCaT cells increased cell adhesion during culture. Our results suggest that VEGFR-2 expressed on HaCaT cells plays a crucial role in VEGF-mediated regulation of cell activity. 相似文献