scholarly journals Effects of inhibiting nitric oxide synthase on cumulus expansion and nuclear maturation of sheep oocytes

2011 ◽  
Vol 56 (No. 6) ◽  
pp. 284-291 ◽  
Author(s):  
Heidari Amale M ◽  
Zare Shahne A ◽  
A. Abavisani ◽  
S. Nasrollahi
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Oocyte Maturation ◽  
In Vitro Maturation ◽  
No Donor ◽  
Cumulus Expansion ◽  
Maturation Medium ◽  
Nos Inhibitor ◽  
Oxide Synthase

Nitric oxide (NO) is a biological signaling molecule that plays a crucial role in oocyte maturation of mammalians. It is generated by the nitric oxide synthase (NOS) enzyme from l-arginine. Although the effect of NO has been shown in oocyte maturation of some species, there is no report about its effect on the in vitro maturation of sheep oocyte. So, this study aimed to investigate the importance of NO/NOS system in the in vitro maturation of ovine oocytes. Different concentrations of L-NAME (a NOS inhibitor) (0.1, 1 and 10mM) were added to maturation medium to evaluate the effect of inhibiting NOS on cumulus expansion and meiotic resumption of sheep oocytes. After 26 h culture, low and medium concentrations of L-NAME (0.1 and 1mM) had no significant effect on cumulus expansion, however, its higher concentration (10mM) decreased percentage of oocytes with total cumulus expansion as compared to control (P < 0.05). The extrusion of the first polar body was also suppressed in a dose-dependent manner, so that the addition of 10mM L-NAME to maturation medium significantly stopped oocytes in GV stage (P < 0.05). Moreover, to confirm the results and to evaluate if this effect is reversible, 0.1mM sodium nitroprusside (SNP, a NO donor) was added only to the maturation medium which had the highest concentration of L-NAME (10mM). The concomitant addition of NOS inhibitor with NO donor reversed the inhibitory effect of L-NAME on cumulus expansion and meiotic maturation. These results indicated that NO/NOS system is involved in the maturation of sheep oocytes.

scholarly journals Nitric oxide synthase acutely regulates progesterone production by in vitro cultured rabbit corpora lutea

1999 ◽  
Vol 160 (2) ◽  
pp. 275-283 ◽  
Author(s):  
A Gobbetti ◽  
C Boiti ◽  
C Canali ◽  
M Zerani
Keyword(s):  
Nitric Oxide ◽  
In Vitro Release ◽  
Inhibitory Effect ◽  
Corpora Lutea ◽  
No Donor ◽  
Nos Inhibitor ◽  
Oxide Synthase ◽  
Vitro Release

We examined the presence and the regulation of nitric oxide (NO) synthase (NOS) using in vitro cultured corpora lutea (CL) obtained from rabbits at days 4 and 9 of pseudopregnancy. The role of NO and NOS on steroidogenesis was also investigated using the same CL preparations after short-term incubations (30 min and 2 h) with the NO donor, sodium nitroprusside (NP), the NOS inhibitor, Nomega-nitro-l-arginine methyl ester (l-NAME) and prostaglandin (PG) F-2alpha. The basal NOS activity was greater in CL at day 4 than at day 9, and was also differently modulated by PGF-2alpha, depending on the age of the CL. The addition of PGF-2alpha to day 4 CL had no effect, but PGF-2alpha on day 9 caused a threefold increase in NOS activity. NP caused a two- to fivefold decrease in release of progesterone from CL of both ages, and this inhibitory effect on steroidogenesis was reversed by l-NAME. All treatments failed to modify basal androgens and 17beta-oestradiol was not detectable in either control or treated CL. These results suggest that NO is effectively involved in the regulation process of steroidogenesis, independently of 17beta-oestradiol. PGF-2alpha had no effect on day 4, but induced luteolysis on day 9, by reducing progesterone (P</=0. 01) to about 18% of control. The luteolytic action of PGF-2alpha was completely reversed by co-incubation with l-NAME, thus supporting the hypothesis that luteolysis is mediated by NO. The addition of NP or l-NAME did not modify the in vitro release of PGF-2alpha. We hypothesised that PGF-2alpha upregulates NOS activity and, consequently, the production of NO, which acutely inhibits progesterone release from day 9 CL of pseudopregnant rabbits.

scholarly journals Islet constitutive nitric oxide synthase and glucose regulation of insulin release in mice

1999 ◽  
Vol 163 (1) ◽  
pp. 39-48 ◽  
Author(s):  
B Akesson ◽  
R Henningsson ◽  
A Salehi ◽  
I Lundquist
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Insulin Release ◽  
Ex Vivo ◽  
Insulin Response ◽  
Glucose Regulation ◽  
Nos Inhibitor ◽  
Oxide Synthase

We have studied, by a combined in vitro and in vivo approach, the relation between the inhibitory action of N(G)-nitro-l-arginine methyl ester (L-NAME), a selective inhibitor of nitric oxide synthase (NOS), on the activity of islet constitutive NOS (cNOS) and glucose regulation of islet hormone release in mice. The cNOS activity in islets incubated in vitro at 20 mM glucose was not appreciably affected by 0.05 or 0.5 mM L-NAME, but was greatly suppressed (-60%) by 5 mM L-NAME. Similarly, glucose-stimulated insulin release was unaffected by the lower concentrations of L-NAME but greatly enhanced in the presence of 5 mM of the NOS inhibitor. In incubated islets inhibition of cNOS activity resulted in a modestly enhanced insulin release in the absence of glucose, did not display any effect at physiological or subphysiological glucose concentrations, but resulted in a markedly potentiated insulin release at hyperglycaemic glucose concentrations. In the absence of glucose, glucagon secretion was suppressed by L-NAME. The dynamics of glucose-induced insulin release and (45)Ca(2+) efflux from perifused islets revealed that L-NAME caused an immediate potentiation of insulin release, and a slight increase in (45)Ca(2+) efflux. In islets depolarized with 30 mM K(+) in the presence of the K(+)(ATP) channel opener, diazoxide, L-NAME still greatly potentiated glucose-induced insulin release. Finally, an i.v. injection of glucose to mice pretreated with L-NAME was followed by a markedly potentiated insulin response, and an improved glucose tolerance. In accordance, islets isolated directly ex vivo after L-NAME injection displayed a markedly reduced cNOS activity. In conclusion, we have shown here, for the first time, that biochemically verified suppression of islet cNOS activity, induced by the NOS inhibitor L-NAME, is accompanied by a marked potentiation of glucose-stimulated insulin release both in vitro and in vivo. The major action of NO to inhibit glucose-induced insulin release is probably not primarily linked to changes in Ca(2+) fluxes and is exerted mainly independently of membrane depolarization events.

scholarly journals CYP1B1 and endothelial nitric oxide synthase combine to sustain proangiogenic functions of endothelial cells under hyperoxic stress

2010 ◽  
Vol 298 (3) ◽  
pp. C665-C678 ◽  
Author(s):  
Yixin Tang ◽  
Elizabeth A. Scheef ◽  
Zafer Gurel ◽  
Christine M. Sorenson ◽  
Colin R. Jefcoate ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Wild Type ◽  
Enos Expression ◽  
No Donor ◽  
Enos Activity ◽  
Oxide Synthase

We have recently shown that deletion of constitutively expressed CYP1B1 is associated with attenuation of retinal endothelial cell (EC) capillary morphogenesis (CM) in vitro and angiogenesis in vivo. This was largely caused by increased intracellular oxidative stress and increased production of thrombospondin-2, an endogenous inhibitor of angiogenesis. Here, we demonstrate that endothelium nitric oxide synthase (eNOS) expression is dramatically decreased in the ECs prepared from retina, lung, heart, and aorta of CYP1B1-deficient (CYP1B1−/−) mice compared with wild-type (CYP1B1+/+) mice. The eNOS expression was also decreased in retinal vasculature of CYP1B1−/− mice. Inhibition of eNOS activity in cultured CYP1B1+/+ retinal ECs blocked CM and was concomitant with increased oxidative stress, like in CYP1B1−/− retinal ECs. In addition, expression of eNOS in CYP1B1−/− retinal ECs or their incubation with a nitric oxide (NO) donor enhanced NO levels, lowered oxidative stress, and improved cell migration and CM. Inhibition of CYP1B1 activity in the CYP1B1+/+ retinal ECs resulted in reduced NO levels and attenuation of CM. In contrast, expression of CYP1B1 increased NO levels and enhanced CM of CYP1B1−/− retinal ECs. Furthermore, attenuation of CYP1B1 expression with small interfering RNA proportionally lowered eNOS expression and NO levels in wild-type cells. Together, our results link CYP1B1 metabolism in retinal ECs with sustained eNOS activity and NO synthesis and/or bioavailability and low oxidative stress and thrombospondin-2 expression. Thus CYP1B1 and eNOS cooperate in different ways to lower oxidative stress and thereby to promote CM in vitro and angiogenesis in vivo.

scholarly journals Effects of nitric oxide synthase inhibition on goat oocyte meiotic maturation

2013 ◽  
Vol 56 (1) ◽  
pp. 255-263
Author(s):  
M. H. Amale ◽  
A. Z. Shahneh ◽  
S. Nasrollahi
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Inhibitory Effect ◽  
Nitric Oxide Donor ◽  
Meiotic Maturation ◽  
Dependent Manner ◽  
Cumulus Expansion ◽  
Maturation Medium ◽  
First Polar Body ◽  
Oxide Synthase

Abstract. Nitric oxide is a biological signalling molecule that plays a crucial role in oocyte maturation of mammalians. It is generated by the nitric oxide synthase enzyme from L-arginine. In this study we assessed the effect of nitric oxide synthase inhibition by Nω-nitro-L-arginine methyl ester (L-NAME) on meiotic maturation of goat oocytes. So, different concentrations of L-NAME (0.1, 1, 10 mM) were added to the maturation medium to evaluate the effect of inhibiting nitric oxide synthase on cumulus expansion and meiotic resumption of goat oocytes. The results showed that none of the concentrations affected cumulus expansion but the formation of the first polar body of the oocytes was suppressed in a dose dependent manner. The highest inhibitory effect was observed with 10 mM L-NAME. Moreover, to confirm the results and to evaluate whether this effect is reversible, 0.1 mM sodium nitroprusside (a nitric oxide donor) was added only to the maturation medium which had the highest concentration of L-NAME (10 mM). The concomitant addition of nitric oxide synthase inhibitor with nitric oxide donor reversed the inhibitory effect of L-NAME on meiotic maturation. These results indicated that the nitric oxide / nitric oxide synthase system is involved in the maturation of goat oocytes and that nitric oxide requirement for nuclear maturation is higher than that for cumulus expansion.

scholarly journals Nitric oxide synthase-mediated early nitric oxide-burst alleviates drought-induced oxidative damage in ammonium supplied-rice roots

2018 ◽  
Author(s):  
Cao Xiaochuang ◽  
Zhu Chunquan ◽  
Zhong Chu ◽  
Zhang Junhua ◽  
Zhu Lianfeng ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Oxidative Damage ◽  
Protective Role ◽  
Antioxidant Defenses ◽  
No Production ◽  
No Donor ◽  
Rice Roots ◽  
Nos Inhibitor ◽  
Oxide Synthase

AbstractAmmonium (NH4+) can enhance rice drought tolerance in comparison to nitrate (NO3-). The mechanism underpinning this relationship was investigated based on the time-dependent nitric oxide (NO) production and its protective role in oxidative stress of NH4+-/NO3--supplied rice under drought. An early burst of NO was induced by drought 3h after root NH4+ treatment but not after NO3- treatment. Root oxidative damage induced by drought was significantly higher in NO3- than in NH4+-treatment due to its reactive oxygen species accumulation. Inducing NO production by applying NO donor 3h after NO3- treatment alleviated the oxidative damage, while inhibiting the early NO burst increased root oxidative damage in NH4+ treatment. Application of nitric oxide synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) completely suppressed NO synthesis in roots 3h after NH4+ treatment and aggravated drought-induced oxidative damage, indicating the aggravation of oxidative damage might have resulted from changes in NOS-mediated early NO burst. Drought also increased root antioxidant enzymes activities, which were further induced by NO donor but repressed by NO scavenger and NOS inhibitor in NH4+-treated roots. Thus, the NOS-mediated early NO burst plays an important role in alleviating oxidative damage induced by drought by enhancing antioxidant defenses in NH4+-supplied rice roots.HighlightNOS-mediated early NO burst plays an important role in alleviating oxidative damage induced by water stress, by enhancing the antioxidant defenses in roots supplemented with NH4+

Increased prostaglandin E generation and enhanced nitric oxide synthase activity in the non-insulin-dependent diabetic embryo during organogenesis

1998 ◽  
Vol 10 (2) ◽  
pp. 191 ◽  
Author(s):  
Alicia Jawerbaum ◽  
Elida T. Gonzalez ◽  
Virginia Novaro ◽  
Alicia Faletti ◽  
Debora Sinner ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Congenital Abnormalities ◽  
Prostaglandin E ◽  
No Donor ◽  
Insulin Dependent ◽  
Nos Inhibitor ◽  
Insulin Dependent Diabetic ◽  
Oxide Synthase

Embryonic development, prostaglandin E (PGE) generation and nitric oxide synthase (NOS) activity during organogenesis were evaluated in an experimental rat model of non-insulin- dependent diabetes (NIDD) generated by neonatal administration of streptozotocin. Gross malformations were detected in 5% of NIDD embryos and these embryos were all non-viable; in the other 95%, growth was retarded but no congenital abnormalities were found. Control embryos were all alive and not malformed. The NIDD 11-day embryos secreted more PGE into the incubation medium than did controls. The NO donor SIN–1 increased PGE production in both control and NIDD embryos. A NOS inhibitor (L-NMMA) reduced PGE generation in both experimental groups, suggesting a modulatory role of NO on embryonic PGE production. Activity of NOS was higher in NIDD 11-day embryos than in controls. Treatment in vivo of control and NIDD rats (Days 7–11 of gestation) with a NOS inhibitor (L-NAME; 5 mg kg-1 i.p.) reduced embryonic PGE production and induced a higher resorption rate and an increase in neural-tube defects. The results suggest that NO modulates PGE generation in the organogenetic embryo. In the NIDD model, overproduction of NO is observed, this NO probably enhancing embryonic PGE production. The relationship between PGE generation and the appearance of congenital abnormalities is discussed.

SIN-1 reverses attenuation of hypercapnic cerebrovasodilation by nitric oxide synthase inhibitors

1994 ◽  
Vol 267 (1) ◽  
pp. R228-R235 ◽  
Author(s):  
C. Iadecola ◽  
F. Zhang ◽  
X. Xu
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Muscle Relaxation ◽  
Smooth Muscle Relaxation ◽  
Co2 Response ◽  
No Donor ◽  
No Donors ◽  
Doppler Probe ◽  
Nos Inhibitor ◽  
Oxide Synthase

We sought to determine whether the attenuation of the hypercapnic cerebrovasodilation associated with inhibition of nitric oxide synthase (NOS) can be reversed by exogenous NO. Rats were anesthetized (halothane) and ventilated. Neocortical cerebral blood flow (CBF) was monitored by a laser-Doppler probe. The NOS inhibitor N omega-nitro-L-arginine methyl ester (L-NAME; 40 mg/kg iv) reduced resting CBF [-36 +/- 5% (SE); P < 0.01, analysis of variance] and attenuated the increase in CBF elicited by hypercapnia (partial pressure of CO2 = 50-60 mmHg) by 66% (P < 0.01). L-NAME reduced forebrain NOS catalytic activity by 64 +/- 3% (n = 10; P < 0.001). After L-NAME, intracarotid infusion of the NO donor 3-morpholinosydnonimine (SIN-1; n = 6) increased resting CBF and reestablished the CBF increase elicited by hypercapnia (P > 0.05 from before L-NAME). Similarly, infusion of the guanosine 3',5'-cyclic monophosphate (cGMP) analogue 8-bromo-cGMP (n = 6) reversed the L-NAME-induced attenuation of the hypercapnic cerebrovasodilation. The NO-independent vasodilator papaverine (n = 6) increased resting CBF but did not reverse the attenuation of the CO2 response. SIN-1 did not affect the attenuation of the CO2 response induced by indomethacin (n = 6). The observation that NO donors reverse the L-NAME-induced attenuation of the CO2 response suggests that a basal level of NO is required for the vasodilation to occur. The findings are consistent with the hypothesis that NO is not the final mediator of smooth muscle relaxation in hypercapnia.(ABSTRACT TRUNCATED AT 250 WORDS)

Partial inhibition of nitric oxide synthase activity stimulates the nuclear maturation progression of bovine cumulus–oocyte complex in vitro in the presence of hemisections of the follicular walls

Zygote ◽  
2020 ◽  
Vol 28 (5) ◽  
pp. 388-396
Author(s):  
Diego Fernando Dubeibe ◽  
Maria Clara Caldas-Bussiere ◽  
Valter Luiz Maciel ◽  
Wlaisa Sampaio ◽  
Paulo B.D. Gonçalves ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Cumulus Cell ◽  
Membrane Integrity ◽  
Maturation Stage ◽  
Nuclear Maturation ◽  
Cumulus Oocyte Complex ◽  
Maturation Medium ◽  
Oxide Synthase

SummaryThis study aimed to assess the effects of the inhibition of nitric oxide synthase (NOS) on events that modulate bovine in vitro oocyte maturation. Cumulus–oocyte complexes (COCs) were cultured with hemisections (HSs) of the follicular walls in a maturation medium supplemented with different concentrations (0.1–10.0 mM) of Nω-nitro-l-arginine methyl ester hydrochloride (l-NAME). Controls consisted of COCs cultured in the presence (+HSs) or absence of HSs (–HSs) with no additional l-NAME supplementation. The following parameters were assessed: oocyte nuclear maturation stage; cumulus cell (CC) membrane integrity; nitrate/nitrite, progesterone, and estradiol concentrations in the culture medium at 22 h of cultivation; and the concentrations of cGMP and cAMP in COCs during the first hour of maturation. The addition of 1.0 mM l-NAME increased the percentage of oocytes that reached metaphase II (MII) and the percentage of intact CCs (P < 0.05). All l-NAME concentrations reduced the nitrate/nitrite concentrations (P < 0.05), but none affected steroid concentrations compared with control +HSs (P > 0.05). The addition of 1.0 mM l-NAME reduced cGMP concentrations at 3 h and increased cAMP concentrations in the first hour of culture (P < 0.05). Our findings suggest that the NOS/NO/cGMP pathway participates in meiosis progression (MI to MII) of the bovine oocytes matured in vitro in the presence of hemisections of the follicular walls. Lastly, the mechanisms that lead to the progression of meiosis after NOS inhibition do not involve changes in steroid production.

Nebivolol-induced vasodilation of renal afferent arterioles involves β3-adrenergic receptor and nitric oxide synthase activation

2012 ◽  
Vol 303 (5) ◽  
pp. F775-F782 ◽  
Author(s):  
Ming-Guo Feng ◽  
Minolfa C. Prieto ◽  
L. Gabriel Navar
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Soluble Guanylate Cyclase ◽  
Adrenergic Blocker ◽  
Afferent Arterioles ◽  
Renal Microvasculature ◽  
Nos Inhibitor ◽  
Oxide Synthase ◽  
Arteriolar Vasodilation

Nebivolol is a β1-adrenergic blocker that also elicits renal vasodilation and increases the glomerular filtration rate (GFR). However, its direct actions on the renal microvasculature and vasodilator mechanism have not been established. We used the in vitro blood-perfused juxtamedullary nephron technique to determine the vasodilator effects of nebivolol and to test the hypothesis that nebivolol induces vasodilation of renal afferent arterioles via an nitric oxide synthase (NOS)/nitric oxide (NO)/soluble guanylate cyclase (sGC)/cGMP pathway and the afferent arteriolar vasodilation effect may be mediated through the release of NO by activation of NOS via a β3-adrenoceptor-dependent mechanism. Juxtamedullary nephrons were superfused with nebivolol either alone or combined with the sGC inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) or the NOS inhibitor Nω-nitro-l-arginine (l-NNA) or the β-blockers metoprolol (β1), butoxamine (β2), and SR59230A (β3). Nebivolol (100 μmol/l) markedly increased afferent and efferent arteriolar diameters by 18.9 ± 3.0 and 15.8 ± 1.8%. Pretreatment with l-NNA (1,000 μmol/l) or ODQ (10 μmol/l) decreased afferent vasodilator diameters and prevented the vasodilator effects of nebivolol (2.0 ± 0.2 and 2.4 ± 0.6%). Metoprolol did not elicit significant changes in afferent vasodilator diameters and did not prevent the effects of nebivolol to vasodilate afferent arterioles. However, treatment with SR59230A, but not butoxamine, markedly attenuated the vasodilation responses to nebivolol. Using a monoclonal antibody to β3-receptors revealed predominant immunostaining on vascular and glomerular endothelial cells. These data indicate that nebivolol vasodilates both afferent and efferent arterioles and that the afferent vasodilator effect is via a mechanism that is independent of β1-receptors but is predominantly mediated via a NOS/NO/sGC/cGMP-dependent mechanisms initiated by activation of endothelial β3-receptors.

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