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Superoxide radicals stimulate IP sub 3 -induced Ca sup 2+ -release from vascular smooth muscle sarcoplasmic reticulum

Conference · · FASEB Journal (Federation of American Societies for Experimental Biology); (United States)
OSTI ID:5145083
;  [1]
  1. Medical College of Virginia, Richmond (United States)
Oxygen free radicals have been implicated in a variety of pathophysiological conditions and vascular smooth muscle can be a site of damage in such oxygen toxicity. Mechanisms of the effects of these radials on the vascular smooth muscle at the cellular level, however, have not been well studied. In the present study, the authors report that the inositol 1,4,5-trisphosphate (IP{sub 3})-induced Ca{sup 2+}-release from bovine aortic SR was also affected by O{sub 2}{sup {minus}}. Hypoxanthine plus xanthine oxidase in the presence of catalase stimulated the IP{sub 3}-induced Ca{sup 2+}-release from SR monitored using arsenazo III. At 10 {mu}M IP{sub 3}, the release was doubled by O{sub 2}{sup {minus}} treatment. As a consequence of using higher SR protein concentrations required to observe the Ca{sup 2+}-uptake inhibition induced by O{sub 2}{sup {minus}}. Since the effect of O{sub 2}{sup {minus}} was not seen when a non-hydrolyzable analogue of IP{sub 3} is used to induce Ca{sup 2+}-release, O{sub 2}{sup {minus}} may be inhibiting the degradation processes of IP{sub 3} rather than having an influence on the release channel per se.
OSTI ID:
5145083
Report Number(s):
CONF-9104107--
Conference Information:
Journal Name: FASEB Journal (Federation of American Societies for Experimental Biology); (United States) Journal Volume: 5:5
Country of Publication:
United States
Language:
English