摘要:

AbstractIn fura‐2‐loaded human periodontal ligament (HPDL) cells, bradykinin induced a rapidly transient increase and subsequently sustained increase in cytosolic Ca2+([Ca2+]i). When external Ca2+was chelated by EGTA, the transient peak of [Ca2+]iwas reduced and the sustained level was abolished, implying the Ca2+mobilization consists of intracellular Ca2+release and Ca2+influx. Thapsigargin, a specific Ca2+‐ATPase inhibitor for inositol 1,4,5‐trisphosphate (1,4,5‐1P3)‐sensitive Ca2+pool, induced an increase in [Ca2+]iin the absence of external Ca2+. After depletion of the intracellular Ca2+pool by thapsigargin, the increase in [Ca2+]iinduced by bradykinin was obviously reduced. Bradykinin also stimulated formation of inositol polyphosphates including 1,4,5‐IP3. These results suggest that bradykinin stimulates intracellular Ca2+release from the 1,4,5‐1P3‐sensitive Ca2+pool. Bradykinin stimulated prostaglandin E2(PGE2) release in the presence of external Ca2+, but not in the absence of external Ca2+. Ca2+ionophore A23187 and thapsigargin evoked the release of PGE2in the presence of external Ca2+despite no activation of bradykinin receptors. These results indicate that bradykinin induces Ca2+mobilization via activation of phospholipase C and PGE2release caused by the Ca2+inf

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1113

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractEndothelin (ET) receptors on chondrocytes were demonstrated using cultured rabbit costal chondrocytes. After crosslinking the receptors on the cells with125I‐ET‐1, two major bands of 43 kDa and 46 kDa were separated by SDS‐PAGE. Scatchard analysis demonstrated two classes of ET receptors with Kdvalues of 1 × 10−10M and 5 × 10−9M. The numbers of high‐ and low‐ affinity receptors were 1 × 104and 2 × 105per cell, respectively. The binding of ET‐1 to chondrocytes was increased by treatment with PTH, DBcAMP, TGF‐β1, IL‐1β, RA and EGF. ET‐1 stimulated DNA synthesis in cultured rabbit chondrocytes. ET‐1 also stimulated calcium incorporation through the cell membrane of chondrocytes. These findings indicate that ET‐1 has a physiological effect on chondrocytes

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1114

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractIn this paper we describe an experimental investigation of the mechanism of motility of vertebrate cells. Human glioma cells were treated with neomycin, an inhibitor of the phosphatidylinositol cycle; and changes in cell motility and the cytoskeleton were examined by video, fluorescence, and scanning electron microscopy and by cytofluorometry. Neomycin stimulates a single protrusion of lamellipodia from the cell margin, which is correlated with an initial rapid decrease in the amount of F‐actin throughout the cell, especially at the cell edge; the fragmentation of actin filaments within the lamellipodia; and the subsequent de novo polymerization of F‐actin in a marginal band at the leading edge of lamellipodia. Changes in F‐actin are paralleled by changes in the distribution and amount of gelsolin. These results support the hypothesis that protrusion is initiated by the gelsolin‐mediated severing and subsequent depolymerization of cortical actin filaments, which weakens the cell cortex, allowing hydrostatic or gel osmotic pressure to force the cell margin to protrude. The accompanying polymerization of filaments actin at the leading edge of the protrusion may stabilize the protrusion and support its ex

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1115

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractSea urchin embryos of the species Paracentrotus lividus were treated continuously with different concentrations of all‐trans retinoic acid (RA) or dimethylsulfoxide (DMSO) at different developmental stages. A delay in embryonic development was observed when embryos were cultured in the presence of 2x10−5M RA, between 1 and 12 hours of development. Hence, at 48 hours of development, while control embryos had reached the pluteus stage, RA‐treated embryos were at the prism stage. At 72 hours of development RA‐treated embryos recovered and continued normal development reaching the pluteus stage. No effect was observed when treatment was performed before 1 hour or after 12 hours of developmet. DMSO treatment had no effect on normal sea urchin embryo development, although we observed that pigment cells, clearly visible at the pluteus stage, become visible earlier with respect to control embryos. This report confirms the advantages that the sea urchin embryo offers for the study of problems in cellular and developmental

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1116

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractIn this paper, we show that the antioxidant N‐acetyl‐cysteine (NAC) is capable of enhancing the adhesion properties of the epithelial cell line A431 and of the lymphocytic cells with cytotoxic activitv from human peripheral blood: the natural killer (NK) cells. This effect leads to an increased efficiency of A431 cells to form a monolayer and of NK cells to kill their targets. In both cases a specific effect of NAC was found in the distribution of those molecules of the cytoskeleton which are generally involved in cell substrate and cell‐to‐cell contact region formation, e.g., the actin microfilaments. NAC could thus behave as a drug influencing certain cytoskeleton‐dependent cell processes in a non‐histotype depen

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1117

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractIn vivo, the neurotoxin MPTP is oxidated to MPP+, which is toxic to dopaminergic neurons. In this paper, we have used MPP+as a tool to evoke neurotoxicity in the PC12 cell line and investigate the intracellular events that are involved. A cytotoxicity test, performed on undifferentiated and NGF‐differentiated PC12 cells, showed that MPP+is much more toxic on differentiated cells and indicated the suitable range of concentrations for studying the starting events evoked by the neurotoxin. By indirect immunofluorescence we have shown that the localisation of α ‐ and β ‐tubulin in NGF‐differentiated cells was modified by a 24 h treatment with 15 μmol/l MPP+. A biochemical analysis was performed on cell extracts and the results showed that MPP+treatment induced an increase in α ‐tubulin levels and a decrease in β ‐tubulin levels. These results suggest the involvement of the two microtubule proteins in MPP+neurotoxicity on NGF‐differe

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1118

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1119

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1120

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1121

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1122

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY