Affiliation:
1. From the Department of Obstetrics, Gynecology and Reproductive Sciences and Magee-Womens Research Institute, University of Pittsburgh (Pa).
Abstract
Abstract
The endothelium serves many functional roles, including the modulation of vascular smooth muscle tone through the release of vasoactive agents such as nitric oxide (NO) and the eicosanoids. We proposed that NO produced by endothelial cells would increase the production of eicosanoids through enhanced expression and/or activation of prostaglandin H synthase. NO and eicosanoid synthesis were stimulated in a bovine coronary microvessel endothelial cell line with the calcium ionophore A23187 (1 μmol/L). Our data demonstrated the following: (1) A23187 stimulated NO synthesis along with prostacyclin and thromboxane production. (2) Inhibition of NO synthesis with
N
G
-nitro-
l
-arginine methyl ester (0.1 mmol/L) significantly diminished both prostacyclin and thromboxane production. (3) Cells incubated with hemoglobin (2 μg/mL), which inactivates NO, decreased A23187-stimulated prostacyclin production, whereas cells incubated with superoxide dismutase (20 U/mL), which protects NO from superoxide anions, enhanced prostacyclin production. (4) Exogenous NO stimulated prostacyclin production. (5) The interaction of NO with prostacyclin persisted in the presence of excess exogenous arachidonic acid (100 μmol/L). (6) Cyclooxygenase activity in cell lysates increased in the first hour of NO stimulation. (7) NO stimulation of prostacyclin occurred within 1 hour and continued for 8 hours. (8) Neither constitutive nor inducible prostaglandin H synthase enzyme expression was altered by NO. (9) Cycloheximide (10 μmol/L) had no effect on A23187 stimulation of prostacyclin production. (10) Exogenous cGMP (10 μmol/L) or a phosphodiesterase inhibitor (1 mmol/L) did not affect prostacyclin production. These data indicate that stimulating synthesis of endogenous NO in cultured endothelial cells increased eicosanoid production through activation of prostaglandin H synthase.
Publisher
Ovid Technologies (Wolters Kluwer Health)
Subject
Cardiology and Cardiovascular Medicine,Physiology
Cited by
233 articles.
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