Induction of nitric oxide synthase in rat gastric smooth muscle preparations

1997 ◽  
Vol 273 (5) ◽  
pp. G1101-G1107 ◽  
Author(s):  
Xi-Long Zheng ◽  
Keith A. Sharkey ◽  
Morley D. Hollenberg
Keyword(s):  
Nitric Oxide ◽  
Smooth Muscle ◽  
Nitric Oxide Synthase ◽  
Time Course ◽  
Inos Mrna ◽  
Organ Bath ◽  
Relaxant Response ◽  
Oxide Synthase ◽  
Inos Induction

The induction in vitro of inducible nitric oxide synthase (iNOS) in intact gastric circular (CM) and longitudinal (LM) smooth muscle preparations was evaluated 1) pharmacologically, by the appearance of 1 mM l-arginine (l-Arg)-induced relaxation in a precontracted tissue; 2) biochemically, according to the appearance of iNOS mRNA using a reverse transcriptase-polymerase chain reaction; and 3) immunohistochemically, using an iNOS-specific antibody. Functionally, iNOS induction affected the contractile properties of the CM but not the LM preparation. The time course of iNOS induction monitored pharmacologically paralleled exactly the appearance of iNOS mRNA. The relaxant response to l-Arg in iNOS-induced CM tissues was blocked by the iNOS inhibitor aminoguanidine and by the guanylyl cyclase inhibitor LY-83583. The addition of oxyhemoglobin to the organ bath also attenuated the relaxant response, but tetrodotoxin had no effect. The transcriptional inhibitor actinomycin D completely blocked iNOS induction as assessed by both pharmacological and biochemical criteria. In iNOS-induced preparations the iNOS immunoreactivity was not detected in the smooth muscle elements but was localized in a layer of macrophage-related cells that were in apposition to the CM smooth muscle elements. We conclude that the spontaneous induction of iNOS in rat gastric tissue can affect the pharmacomechanical reactivity of the CM elements and that this regulation of the CM contractility is due to the induction of iNOS in a set of macrophage-related cells that are closely apposed to the CM elements so that they selectively affect only the contractility of the CM preparation.

Interleukin-1β, Src- and non-Src tyrosine kinases, and nitric oxide synthase induction in rat aorta in vitro

2000 ◽  
Vol 279 (2) ◽  
pp. H566-H576 ◽  
Author(s):  
Yu Gui ◽  
Xi-Long Zheng ◽  
Morley D. Hollenberg
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Tyrosine Kinases ◽  
Rat Aorta ◽  
Interleukin 1Β ◽  
Inos Mrna ◽  
Src Tyrosine Kinases ◽  
Oxide Synthase ◽  
Inos Induction

We studied the potential roles for endogenous interleukin-1β (IL-1β) and for several signaling pathways in the spontaneous induction in vitro of inducible nitric oxide synthase (iNOS) in endothelium-denuded rat aorta rings. Added IL-1β augmented, whereas the IL-1β receptor antagonist IL-1ra blocked, spontaneous iNOS induction. Furthermore, increases in IL-1β mRNA preceded those of iNOS mRNA. Mitogen-activated protein kinase kinase and phosphatidyl inositol 3′ kinase inhibition did not block iNOS induction, whereas nuclear factor κB inhibition did. The sarcoma virus tyrosine kinase (Src) family-selective inhibitor 4-amino-5(4-methylphenyl)-7-( t-butyl)pyrazolo[3,4-d]pyrimidine (PP1) blocked the upregulation of IL-1β mRNA and the subsequent induction of iNOS but not the induction of iNOS stimulated by exogenously added IL-1β. In contrast, the non-Src inhibitors TP 47/AG 213 and genistein and the tyrosine phosphatase inhibitor vanadate did not affect the spontaneous upregulation of IL-1β mRNA but blocked both the IL-1β-mediated and spontaneous induction of iNOS. We conclude that 1) the upregulation of tissue IL-1β, via a signaling pathway involving a Src family kinase, plays a key role in rat vascular iNOS induction and 2) non-Src tyrosine kinases play roles downstream from IL-1β for iNOS induction.

Nitric oxide synthase inhibitors 7- and 6-nitroindazole relax smooth muscle in vitro

1994 ◽  
Vol 256 (1) ◽  
pp. R5-R6 ◽  
Author(s):  
Andrew D. Medhurst ◽  
Carol Greenlees ◽  
Andrew A. Parsons ◽  
Susan J. Smith
Keyword(s):  
Nitric Oxide ◽  
Smooth Muscle ◽  
Nitric Oxide Synthase ◽  
Nitric Oxide Synthase Inhibitors ◽  
Oxide Synthase

scholarly journals Dexamethasone differentially affects interleukin 1β- and cyclic AMP-induced nitric oxide synthase mRNA expression in renal mesangial cells

1994 ◽  
Vol 304 (2) ◽  
pp. 337-340 ◽  
Author(s):  
D Kunz ◽  
G Walker ◽  
J Pfeilschifter
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Cyclic Amp ◽  
Mesangial Cells ◽  
Inos Mrna ◽  
Mrna Levels ◽  
Necrosis Factor Alpha ◽  
Camp Analogue ◽  
Oxide Synthase ◽  
Inos Induction

Inducible nitric oxide synthase (iNOS) is expressed in renal mesangial cells in response to two principal classes of activating signals that interact in a synergistic fashion. These two groups of activators comprise inflammatory cytokines such as interleukin (IL)-1 beta or tumour necrosis factor alpha and agents that elevate cellular levels of cyclic AMP (cAMP). We examined whether dexamethasone differentially affects iNOS induction in response to IL-1 beta and a membrane-permeable cAMP analogue, N6,O-2′-dibutyryladenosine 3′,5′-phosphate (Bt2cAMP). Nanomolar concentrations of dexamethasone suppress IL-1 beta- as well as Bt2cAMP-induced iNOS protein expression and production of nitrite, the stable end product of nitric oxide (NO) formation. In contrast, dexamethasone prevents induction of iNOS mRNA in response to Bt2cAMP without affecting IL-1 beta-triggered increase in iNOS mRNA levels. These data suggest that dexamethasone acts at different levels, depending on the stimulus used to suppress iNOS induction in mesangial cells.

Effects of ischemia on cerebrovascular responses to N-methyl-D-aspartate in piglets

1996 ◽  
Vol 270 (4) ◽  
pp. H1225-H1230 ◽  
Author(s):  
D. W. Busija ◽  
W. Meng ◽  
F. Bari ◽  
P. S. McGough ◽  
R. A. Errico ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Superoxide Dismutase ◽  
Smooth Muscle ◽  
Intracranial Pressure ◽  
Nitric Oxide Synthase ◽  
Before And After ◽  
Newborn Pigs ◽  
Oxide Synthase ◽  
Enhanced Degradation

We examined the effects of total global ischemia on cerebral arteriolar responses to N-methyl-D-aspartate (NMDA) in anesthetized newborn pigs. Arteriolar responses to 10(-4) M NMDA were determined before and after 10 to 20 min of ischemia caused by increasing intracranial pressure. Before ischemia, NMDA dilated arterioles by 30 +/- 5% (baseline = 88 +/- 2 microns; n = 6). However, after 10 min of ischemia, arteriolar dilation was reduced to 10 +/- 3% at 1 h (P < 0.05). At 2 and 4 h, NMDA-induced dilation was not different from preischemia values. Twenty minutes of ischemia had similar effects. Coadministration of 100 U/ml of superoxide dismutase did not restore arteriolar dilation to NMDA at 1 h after ischemia. Sodium nitroprusside dilated by 14 +/- 3 and 40 +/- 5% at 10(-6) and 10(-5) M before ischemia, respectively, and arteriolar responsiveness was not changed by ischemia (n = 6). Cortical nitric oxide synthase (NOS) activity, measured by the in vitro conversion of L-[14C]arginine to L-[14C]citrulline, was unaffected by ischemia (n = 12). We conclude that decreases in cerebral arteriolar responsiveness to NMDA are not due to impairment of NOS activity, enhanced degradation or chelation of nitric oxide (NO), or reduced vascular smooth muscle responsiveness to NO.

Expression of the inducible nitric oxide synthase gene in diaphragm and skeletal muscle

1996 ◽  
Vol 81 (6) ◽  
pp. 2415-2420 ◽  
Author(s):  
Marita Thompson ◽  
Lisa Becker ◽  
Debbie Bryant ◽  
Gary Williams ◽  
Daniel Levin ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Skeletal Muscle ◽  
Nitric Oxide Synthase ◽  
Inducible Nitric Oxide Synthase ◽  
No Synthase ◽  
Inos Mrna ◽  
Pump Failure ◽  
Oxide Synthase ◽  
Inducible Nitric Oxide

Thompson, Marita, Lisa Becker, Debbie Bryant, Gary Williams, Daniel Levin, Linda Margraf, and Brett P. Giroir. Expression of the inducible nitric oxide synthase gene in diaphragm and skeletal muscle. J. Appl. Physiol. 81(6): 2415–2420, 1996.—Nitric oxide (NO) is a pluripotent molecule that can be secreted by skeletal muscle through the activity of the neuronal constitutive isoform of NO synthase. To determine whether skeletal muscle and diaphragm might also express the macrophage-inducible form of NO synthase (iNOS) during provocative states, we examined tissue from mice at serial times after intravenous administration of Escherichia coli endotoxin. In these studies, iNOS mRNA was strongly expressed in the diaphragm and skeletal muscle of mice 4 h after intravenous endotoxin and was significantly diminished by 8 h after challenge. Induction of iNOS mRNA was followed by expression of iNOS immunoreactive protein on Western immunoblots. Increased iNOS activity was demonstrated by conversion of arginine to citrulline. Immunochemical analysis of diaphragmatic explants exposed to endotoxin in vitro revealed specific iNOS staining in myocytes, in addition to macrophages and endothelium. These results may be important in understanding the pathogenesis of respiratory pump failure during septic shock, as well as skeletal muscle injury during inflammation or metabolic stress.

High-calcium diet enhances vasorelaxation in nitric oxide-deficient hypertension

2000 ◽  
Vol 279 (3) ◽  
pp. H1036-H1043 ◽  
Author(s):  
Pasi Jolma ◽  
Jarkko Kalliovalkama ◽  
Jari-Petteri Tolvanen ◽  
Peeter Kööbi ◽  
Mika Kähönen ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Smooth Muscle ◽  
Nitric Oxide Synthase ◽  
Calcium Supplementation ◽  
Calcium Diet ◽  
High Calcium ◽  
High Calcium Diet ◽  
Increased Sensitivity ◽  
Oxide Synthase

Because the effects of calcium supplementation on arterial tone in nitric oxide-deficient hypertension are unknown, we investigated the influence of elevating dietary calcium from 1.1 to 3.0% in Wistar rats treated with N G-nitro-l-arginine methyl ester (l-NAME; 20 mg · kg−1 · day−1) for 8 wk. A high-calcium diet attenuated the development of hypertension induced by l-NAME and abrogated the associated impairments of endothelium-independent mesenteric arterial relaxations to nitroprusside, isoproterenol, and cromakalim. Endothelium-dependent relaxations to acetylcholine during nitric oxide synthase inhibition in vitro were decreased in l-NAME rats and improved by calcium supplementation. The inhibition of cyclooxygenase by diclofenac augmented the responses to acetylcholine in l-NAME rats but not in calcium + l-NAME rats. When hyperpolarization of smooth muscle was prevented by KCl precontraction, the responses to acetylcholine during combined nitric oxide synthase and cyclooxygenase inhibition were similar in all groups. Furthermore, superoxide dismutase enhanced the acetylcholine-induced relaxations in l-NAME rats but not in calcium + l-NAME rats. In conclusion, calcium supplementation reduced blood pressure during chronic nitric oxide synthase inhibition and abrogated the associated impairments in endothelium-dependent and -independent arterial relaxation. The augmented vasorelaxation after increased calcium intake inl-NAME hypertension may be explained by enhanced hyperpolarization and increased sensitivity to nitric oxide in arterial smooth muscle and decreased vascular production of superoxide and vasoconstrictor prostanoids.

scholarly journals L-Carnitine has a liver-protective effect through inhibition of inducible nitric oxide synthase induction in primary cultured rat hepatocytes

2018 ◽  
Vol 8 (3) ◽  
pp. 212 ◽  
Author(s):  
Yusuke Nakamura ◽  
Hiroya Iida ◽  
Richi Nakatake ◽  
Tatsuma Sakaguchi ◽  
Masaki Kaibori ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Liver Injury ◽  
Inducible Nitric Oxide Synthase ◽  
Inos Mrna ◽  
Type I ◽  
Protective Effects ◽  
Oxide Synthase ◽  
Inducible Nitric Oxide

Background: L-Carnitine has protective effects on various injured organs. However, it has not been reported whether L-carnitine influences the induction of inducible nitric oxide synthase (iNOS) expression during inflammation. Nitric oxide (NO) produced by iNOS is an inflammatory indicator in organs which become inflamed, including the liver.Objective: This study aimed to examine whether L-carnitine influences the induction of iNOS gene expression in inflammatory cytokine-stimulated hepatocytes and the mechanisms involved in the action. Methods: L-Carnitine was added into the primary cultures of rat hepatocytes stimulated by interleukin-1β (an in vitro liver injury model). The production of NO and induction of iNOS and its signaling pathway were analyzed.Results: Transfection experiments with iNOS promoter-luciferase constructs revealed how L-carnitine inhibited iNOS mRNA synthesis activity and reduced its stability. In support of this observation, L-carnitine reduced iNOS mRNA and iNOS protein expression levels, resulting in reduced NO production. L-Carnitine blocked two essential pathways for iNOS induction: IκB kinase (IκB degradation/NF-κB activation) and phosphatidylinositol 3-kinase/Akt (type I IL-1 receptor upregulation).Conclusions: L-Carnitine inhibited the induction of inflammatory mediator iNOS, partially through inhibition of NF-κB activation, which demonstrated L-carnitine has protective effects in an in vitro liver injury model. L-Carnitine may have therapeutic potential for organ injuries, including the liver.Keywords: L-carnitine, hepatic encephalopathy, inducible nitric oxide synthase, liver injury, primary cultured hepatocytes, nuclear factor-κB, type I interleukin-1 receptor 

Relaxin exerts two opposite effects on mechanical activity and nitric oxide synthase expression in the mouse colon

2012 ◽  
Vol 303 (9) ◽  
pp. E1142-E1150 ◽  
Author(s):  
M. C. Baccari ◽  
C. Traini ◽  
R. Garella ◽  
G. Cipriani ◽  
M. G. Vannucchi
Keyword(s):  
Nitric Oxide ◽  
Smooth Muscle ◽  
Nitric Oxide Synthase ◽  
Muscle Tone ◽  
Muscle Relaxation ◽  
Proximal Colon ◽  
Mechanical Activity ◽  
Enos Expression ◽  
Oxide Synthase

The hormone relaxin exerts a variety of functions on the smooth muscle of reproductive and nonreproductive organs, most of which occur through a nitric oxide (NO)-mediated mechanism. In the stomach and ileum, relaxin causes muscle relaxation by modulating the activity and expression of different nitric oxide synthase (NOS) isoforms region-dependently. Nothing is known on the effects of relaxin in the colon, the gut region expressing the highest number of neuronal (n) NOSβ-immunoreactive neurons and mainly involved in motor symptoms of pregnancy and menstrual cycle. Therefore, we studied the effects of relaxin exposure in the mouse proximal colon in vitro evaluating muscle mechanical activity and NOS isoform expression. The functional experiments showed that relaxin decreases muscle tone and increases amplitude of spontaneous contractions; the immunohistochemical results showed that relaxin increases nNOSβ and endothelial (e) NOS expression in the neurons and decreases nNOSα and eNOS expression in the smooth muscle cells (SMC). We hypothesized that, in the colon, relaxin primarily increases the activity and expression of nNOSβ and eNOS in the neurons, causing a reduction of the muscle tone. The downregulation of nNOSα and eNOS expression in the SMC associated with increased muscle contractility could be the consequence of continuous exposue of these cells to the NO of neuronal origin. These findings may help to better understand the physiology of NO in the gastrointestinal tract and the role that the “relaxin-NO” system plays in motor disorders such as functional bowel disease.

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