NO Synthase Expression (no + synthase_expression)

Distribution by Scientific Domains

Selected Abstracts

NADPH-Diaphorase Activity and NO Synthase Expression in the Olfactory Epithelium of the Bovine

S. Wenisch
With 2 figures Summary NADPH-diaphorase (NADPH-d) staining of the bovine olfactory epithelium was compared with the immunohistochemical localization of nitric oxide synthase (NOS), soluble guanylyl cyclase, and cGMP (cyclic guanosine 3,,5,-monophosphate). Out of the three isoforms, only the inducible NOS (NOS-II) was found at the epithelial surface correlating with the strong labelling for NADPH-d. In contrast, light diaphorase staining associated with deeper epithelial regions did not coincide with any NOS immunoreactivity. As there is overlapping expression of NOS-II, soluble guanylyl cyclase and cGMP at the luminal surface morphologically occupied by dendritic knobs of olfactory receptor neurons and microvillar endings of supporting cells, the nitric oxide (NO)/cGMP pathway is likely to be involved in modulating the odour signals during olfactory transduction. [source]

Cytokine-mediated control of lipopolysaccharide-induced activation of small intestinal epithelial cells

IMMUNOLOGY, Issue 3 2007
Michael Lotz
Summary Cytokines with anti-inflammatory properties have been implicated in the prevention of inappropriate immune activation by commensal bacteria in the intestinal tract. Here, we analysed receptor expression, cellular signalling, and the inhibitory activity of interleukin (IL)-4, -10, -11, and -13 as well as of transforming growth factor-, on lipopolysaccharide-mediated small intestinal epithelial cell activation. Only IL-4 and IL-13 had a significant inhibitory effect on chemokine secretion and nitric oxide (NO) production in differentiated and polarized cells. Reverse transcription,polymerase chain reaction of primary intestinal epithelial cells obtained by laser-microdissection confirmed expression of the type II IL-4 receptor consisting of the IL-4 receptor , and the IL-13 receptor ,1. Also, IL-4 or IL-13 led to rapid signal transducer and activator of transcription 6 phosphorylation, diminished inducible NO synthase expression, and enhanced the antagonistic arginase 1 activity. In conclusion, cytokines such as IL-4 and IL-13 affect intestinal epithelial cells and exhibit a modulating activity on Toll-like receptor-4-mediated epithelial cell activation. [source]

Short-term calorie restriction reverses vascular endothelial dysfunction in old mice by increasing nitric oxide and reducing oxidative stress

AGING CELL, Issue 3 2010
Catarina Rippe
Summary To determine if short-term calorie restriction reverses vascular endothelial dysfunction in old mice, old (O, n = 30) and young (Y, n = 10) male B6D2F1 mice were fed ad libitum (AL) or calorie restricted (CR, approximately 30%) for 8 weeks. Ex vivo carotid artery endothelium-dependent dilation (EDD) was impaired in old ad libitum (OAL) vs. young ad libitum (YAL) (74 ± 5 vs. 95 ± 2% of maximum dilation, P < 0.05), whereas old calorie-restricted (OCR) and YCR did not differ (96 ± 1 vs. 94 ± 3%). Impaired EDD in OAL was mediated by reduced nitric oxide (NO) bioavailability associated with decreased endothelial NO synthase expression (aorta) (P < 0.05), both of which were restored in OCR. Nitrotyrosine, a cellular marker of oxidant modification, was markedly elevated in OAL (P < 0.05), whereas OCR was similar to Y. Aortic superoxide production was 150% greater in OAL vs. YAL (P < 0.05), but normalized in OCR, and TEMPOL, a superoxide dismutase (SOD) mimetic that restored EDD in OAL (to 97 ± 2%), had no effect in Y or OCR. OAL had increased expression and activity of the oxidant enzyme, NADPH oxidase, and its inhibition (apocynin) improved EDD, whereas NADPH oxidase in OCR was similar to Y. Manganese SOD activity and sirtuin1 expression were reduced in OAL (P < 0.05), but restored to Y in OCR. Inflammatory cytokines were greater in OAL vs. YAL (P < 0.05), but unaffected by CR. Carotid artery endothelium-independent dilation did not differ among groups. Short-term CR initiated in old age reverses age-associated vascular endothelial dysfunction by restoring NO bioavailability, reducing oxidative stress (via reduced NADPH oxidase,mediated superoxide production and stimulation of anti-oxidant enzyme activity), and upregulation of sirtuin-1. [source]

Endothelial dysfunction in aged humans is related with oxidative stress and vascular inflammation

AGING CELL, Issue 3 2009
Leocadio Rodríguez-Mañas
Summary Vascular endothelial dysfunction occurs during the human aging process, and it is considered as a crucial event in the development of many vasculopathies. We investigated the underlying mechanisms of this process, particularly those related with oxidative stress and inflammation, in the vasculature of subjects aged 18,91 years without cardiovascular disease or risk factors. In isolated mesenteric microvessels from these subjects, an age-dependent impairment of the endothelium-dependent relaxations to bradykinin was observed. Similar results were observed by plethysmography in the forearm blood flow in response to acetylcholine. In microvessels from subjects aged less than 60 years, most of the bradykinin-induced relaxation was due to nitric oxide release while the rest was sensitive to cyclooxygenase (COX) blockade. In microvessels from subjects older than 60 years, this COX-derived vasodilatation was lost but a COX-derived vasoconstriction occurred. Evidence for age-related vascular oxidant and inflammatory environment was observed, which could be related to the development of endothelial dysfunction. Indeed, aged microvessels showed superoxide anions (O2,) and peroxynitrite (ONOO,) formation, enhancement of NADPH oxidase and inducible NO synthase expression. Pharmacological interference of COX, thromboxane A2/prostaglandin H2 receptor, O2,, ONOO,, inducible NO synthase, and NADPH oxidase improved the age-related endothelial dysfunction. In situ vascular nuclear factor-,B activation was enhanced with age, which correlated with endothelial dysfunction. We conclude that the age-dependent endothelial dysfunction in human vessels is due to the combined effect of oxidative stress and vascular wall inflammation. [source]

Nitric oxide in bovine corpus luteum: Possible mechanisms of action in luteolysis

ABSTRACT Although prostaglandin (PG) F2, is considered as the principal luteolytic factor, its action on the bovine corpus luteum (CL) is mediated by other intraovarian factors. Among them, nitric oxide (NO) seems to play a mandatory role in luteolysis. In this article we review the background and current status of work on possible roles of NO in the CL function, based on available information and our own experimental data. NO is produced in all three main types of bovine CL cells: steroidogenic, endothelial and immune cells. PGF2, and some luteolytic cytokines (tumor necrosis factor, interferon) increase NO production and stimulate NO synthase expression in the bovine CL. NO inhibits progesterone production, stimulates the secretion of PGF2, and leukotriene C4, reduces the number of viable luteal cells and, finally, participates in functional luteolysis. NO induces the apoptotic death of CL cells by the modulation of bcl-2 family gene expression and the stimulation of caspase-3 gene expression and activity. However, this simple molecule shows both luteolytic and luteotropic actions during the estrous cycle in ruminants. The aim of this overview is to present and discuss the recent findings crucial for understanding NO role in the process of CL regression in cattle. [source]