التفاصيل البيبلوغرافية
| العنوان: |
Autocrine/paracrine pattern of superoxide production through NAD(P)H oxidase in coronary arterial myocytes. |
| المؤلفون: |
Guo Zhang, Fan Zhang, Muh, Rachel, Fan Yl, Chalupsky, Karel, Hua Cai, Pin-Lan Li |
| المصدر: |
American Journal of Physiology: Heart & Circulatory Physiology; Jan2007, Vol. 292 Issue 1, pH483-495, 13p, 9 Graphs |
| مصطلحات موضوعية: |
AUTOCRINE mechanisms, PARACRINE mechanisms, SUPEROXIDES, CORONARY arteries, MUSCLE cells |
| مستخلص: |
The present study tested the hypothesis that membrane-bound NAD(P)H oxidase in coronary arterial myocytes (CAMs) is capable of producing superoxide (O2·-) toward extracellular space to exert an autocrine- or paracrine-like action in these cells. Using a high-speed wavelength-switching fluorescent microscopic imaging technique, we simultaneously monitored the binding of dihydroethidium-oxidizing product to exogenous salmon testes DNA trapped outside CAMs and to nuclear DNA as indicators of extra- and intracellular O2·- production. It was found that a muscarinic agonist oxotremorine (OXO; 80 µM) increased O2·- levels more rapidly outside than inside CAMs. In the presence of superoxide dismutase (500 U/mI) plus catalase (400 U/mI) and NAD(P)H oxidase inhibitor diphenylene iodonium (50 µM) or apocynin (100 µM), these increases in extra- and intracellular O2·- levels were substantially abolished or attenuated. The O2·- increase outside CAMs was also confirmed by detecting oxidation of nitro blue tetrazolium and confocal microscopic localization of Matrigel-trapped OxyBURST H2HFF Green BSA staining around these cells. By electron spin resonance spectrometry, the extracellular accumulation of O2·- was demonstrated as a superoxide dismutase-sensitive component outside CAMs. Furthermore, RNA interference of NAD(P)H oxidase subunits Nox1 or p47 markedly blocked OXO-induced increases in both extra- and intracellular O2·- levels, whereas small inhibitory RNA of Nox4 only attenuated intracellular O2·- accumulation. These results suggest that Nox1 represents a major NAD(P)H oxidase isoform responsible for extracellular O2·- production. This rapid extracellular production of O2·- seems to be unique to OXO-induced M1-receptor activation, since ANG II-induced intra- and extracellular O2·- increases in parallel. It is concluded that the outward production of O2·- via NAD(P)H oxidase in CAMs may represent an important producing pattern for its autocrine or paracrine actions. [ABSTRACT FROM AUTHOR] |
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| قاعدة البيانات: |
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