The endothelium plays an important role in maintaining vascular homeostasis by synthesizing and releasing several relaxing factors, such as prostacyclin, nitric oxide (NO), and endothelium-derived hyperpolarizing factor (EDHF). We have previously demonstrated in animals and humans that endothelium-derived hydrogen peroxide (H(2)O(2)) is an EDHF that is produced in part by endothelial NO synthas...

INTRODUCTION Nitrite has been found to protect liver graft from cold preservation injury. However, the cell signaling pathway involved in this protection remains unclear. Here, we attempt to clarify if the NOS pathway by using the NOS inhibitor, L-NAME (L-NG-Nitroarginine methyl ester). ANIMALS AND METHODS Rat livers were conserved for 24 h at 4°C in (IGL-1) solution enriched or not with nitr...

BACKGROUND Inducible NO synthase (NOS)-derived peroxynitrite (ONOO-) during ischemia/reperfusion contributes to ischemic brain injury. However, inducible NOS (iNOS) regulation in ischemic stroke remains unknown. Tetrahydrobiopterin (BH4) is an essential cofactor for NOS activity. The present study tested the hypothesis that inhibition of endogenous BH4 rate-limiting enzyme GTP cyclohydrolase I ...

Angiotensin II infusion causes endothelial dysfunction by increasing NAD(P)H oxidase–mediated vascular superoxide production. However, it remains to be elucidated how in vivo angiotensin II treatment may alter the expression of the gp91 isoforms and the endothelial nitric oxide synthase (NOS III) and subsequent signaling events and whether, in addition to the NAD(P)H oxidase, NOS III contribute...

Nucleus accumbens (Nac) has been considered as a center for the induction of drug dependence. Since a high concentration of the enzyme, nitric oxide synthase (NOS) has been found in the Nac, and this fact that the role of nitric oxide (NO) in acquisition and expression of drug dependence has become clear in recent years, therefore in this study the effects of intraaccumbal injections of L-argin...

Chronic systemic platelet cyclooxygenase (COX) inhibition with low-dose aspirin [acetylsalicylic acid (ASA)] significantly attenuates reflex cutaneous vasodilation in middle-aged humans, whereas acute, localized, nonisoform-specific inhibition of vascular COX with intradermal administration of ketorolac does not alter skin blood flow during hyperthermia. Taken together, these data suggest that ...

Full expression of reflex cutaneous vasodilation (VD) is dependent on nitric oxide (NO) and is attenuated with essential hypertension. Decreased NO-dependent VD may be due to 1) increased oxidant stress and/or 2) decreased L-arginine availability through upregulated arginase activity, potentially leading to increased superoxide production through uncoupled NO synthase (NOS). The purpose of this...

Nitric oxide (NO) is a free radical produced by the action of NO synthases (NOS) and is known to be involved in the regulation of many reproductive events that occur in the oviducts. The oviducts are highly specialized organs that play crucial roles in reproduction by providing an optimal environment for the final maturation of gametes, fertilization, and early embryo development. In this study...

Zhu, Longkun, and Pingnian He. Platelet-activating factor increases endothelial [Ca ]i and NO production in individually perfused intact microvessels. Am J Physiol Heart Circ Physiol 288: H2869–H2877, 2005. First published January 21, 2005; doi:10.1152/ajpheart.01080.2004.—We have demonstrated that inhibition of NO synthase (NOS) in endothelial cells by either the NOS inhibitor N -monomethyl-L-...