ISSN:
1573-4919
Keywords:
ultraviolet radiation
;
oxidative stress
;
calcium
;
phospholipase A2
;
thrombin
;
V79 fibroblast
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
Abstract V79 fibroblasts were treated with ultraviolet (UV) C radiation alone as well as in conjunction with chronic oxidative stress. The effects of these treatments on calcium signaling were observed at 30 min post-irradiation. In the absence of extracellular calcium, thrombin released calcium from internal stores of UVC-irradiated V79 fibroblasts even after exposure to neomycin. In neomycin-treated control and chronic oxidative stress cells, no calcium release by thrombin was observed after chelation of external calcium. Calcium release by thrombin from internal stores of UV-irradiated and neomycin-treated cells was completely abolished by pretreatment with N-acetyl cysteine and dexamethasone. Cellular total soluble thiol content which is a good indicator of cellular reduced glutathione (GSH) level was significantly elevated 30 min after ultraviolet radiation, indicating an adaptive response after oxidative stress. Chronic oxidative stress alone resulted in a much smaller increase in GSH but chronic oxidative stress in conjunction with UVC produced a very prominent elevation in GSH levels. Our data suggest that thrombin can cause calcium release from internal stores of ultraviolet-irradiated fibroblasts which is independent of phosphatidylinositol bisphosphate hydrolysis and is directly related to the level of oxidative stress. Involvement of phopholipase A2 and a role for its products as possible mediators of calcium release from intracellular stores, is strongly indicated.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1006957926978
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