Nitric oxide synthase (NOS), the enzyme that catalyzes the formation of nitric oxide from L-arginine, exists in three major isoforms, neuronal, endothelial, and immunologic. Neuronal and endothelial isoforms are constitutively expressed, and require calcium for activation. Both of these isoforms can be induced (i.e., new protein synthesis occurs) under appropriate conditions. The immunologic is...

BACKGROUND Nitric oxide (NO) is a molecule that incorporates in many physiological processes of female reproductive system. Recent studies suggested the possible role of endothelial isoform of nitric oxide synthase (eNOS) enzyme in female infertility. OBJECTIVE The aim of this study is to evaluate the expression of endothelial nitric oxide synthase in endometrial tissue of women with unexplai...

Endothelium-derived nitric oxide (NO) is a mediator of angiogenesis. Vascular endothelial growth factor (VEGF) stimulates the release of NO from cultured human umbilical venous endothelial cells and upregulates the expression of nitric oxide synthase (NOS).1,2 Segments of rabbit thoracic aorta release NO in response to VEGF; preincubation with L-arginine increases basal and VEGFstimulated NO re...

OBJECTIVE A risk factor for cardiovascular disease, hyperhomocystinemia (HHcy), is associated with endothelial dysfunction. In this study, we examined the mechanistic role of HHcy in endothelial dysfunction. METHODS AND RESULTS Through the use of 2 functional models, aortic rings and intravital video microscopy of the cremaster, we found that arterial relaxation in response to the endothelium...

Endothelial dysfunction is prevalent in chronic kidney disease. This study tested the hypothesis that transfusion of rat aortic endothelial cells (ECs) ameliorates endothelial dysfunction in a rat model of chronic kidney disease. Male Sprague-Dawley rats underwent sham surgery or 5/6 nephrectomy (Nx). Five weeks after Nx, EC (1.5 × 10(6) cells/rat) or vehicle were transfused intravenously. One ...

BACKGROUND We hypothesized that cytomegalovirus (CMV) may contribute to the vasculopathy observed in cardiac allograft recipients by impairing the endothelial nitric oxide synthase pathway. We focused on asymmetric dimethylarginine (ADMA, the endogenous inhibitor of nitric oxide synthase) as a potential mediator of the adverse vascular effect of CMV. METHODS AND RESULTS Heart transplant recip...

Despite the complex vascular effects of dexmedetomidine (DEX), its actions on human pulmonary resistance arteries remain unknown. The present study tested the hypothesis that DEX inhibits vascular tension in human pulmonary arteries through the endothelial nitric oxide synthase (eNOS) mediated production of nitric oxide (NO). Pulmonary artery segments were obtained from 62 patients who underwen...

BACKGROUND Recent studies demonstrate that spatially restricted, local Ca2+ signals are key regulators of endothelium-dependent vasodilation in systemic circulation. There are drastic functional differences between pulmonary arteries (PAs) and systemic arteries, but the local Ca2+ signals that control endothelium-dependent vasodilation of PAs are not known. Localized, unitary Ca2+ influx events...

BACKGROUND Nitric oxide synthase uncoupling occurs under conditions of oxidative stress modifying the enzyme's function so it generates superoxide rather than nitric oxide. Nitric oxide synthase uncoupling occurs with chronic pressure overload, and both are ameliorated by exogenous tetrahydrobiopterin (BH4)-a cofactor required for normal nitric oxide synthase function-supporting a pathophysiolo...

background: migraine is a chronic  neurological  disorder, characterized  by recurrent  moderate to severe headaches. worldwide migraine a=ects nearly 15%. studies suggest that genes involved in the production of nitric oxide (no) may act as genetic  factors for migraine. no synthase  3 (nos3) by expressing  enzyme nos regulates  endothelial  derived no. one  class of  medications   used  as  f...