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Çalışkan Ş, Narin MA, Dede FS, Narin R, Dede H, Kandemir Ö. Glyceryl trinitrate for the treatment of preterm labor. J Turk Ger Gynecol Assoc 2015; 16:174-8. [PMID: 26401112 DOI: 10.5152/jtgga.2015.15016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 03/24/2015] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE This study was conducted to compare the tocolytic efficacy of glyceryltrinitrate (GTN) with that of magnesium sulfate (MgSO4) and to investigate serum nitric oxide metabolites before and after tocolysis. MATERIAL AND METHODS In total, 48 women between 27 and 34 weeks' gestation with threatened preterm labor and intact membranes were randomly allocated to receive either GTN or MgSO4 tocolysis. Main outcome measures included tocolytic efficacy and maternal side effect(s) of the tocolytic agent. Obstetric and neonatal outcomes as well as pretreatment and posttreatment nitric oxide (NO) metabolites were assessed. RESULTS Forty-one patients were included into the final analysis. Uterine contraction cessation times were 3.66±1.28 and 6.83±3.47 hours for GTN and MgSO4 groups, respectively. Similarly, maternal side effects were significantly lower in the GTN group than in the MgSO4 group, and no serious maternal side effects were recorded. Serum NO metabolite levels before treatment were significantly lower in the treatment groups than in the controls. Serum nitrite levels were significantly increased after tocolytic treatment both in MgSO4 and GTN groups. CONCLUSION GTN effectively delays preterm delivery and reduces neonatal morbidity and mortality with less maternal side effects and seems to be an effective and safe alternative to MgSO4.
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Affiliation(s)
- Şafak Çalışkan
- Clinic of Obstetrics and Gynecology, Nazilli State Hospital, Aydın, Turkey
| | - Mehmet Ali Narin
- Department of Obstetrics and Gynecology, Erzincan University Faculty of Medicine, Erzincan, Turkey
| | - Faruk Suat Dede
- Clinic of Obstetrics and Gynecology, Etlik Zübeyde Hanım Training and Research Hospital Ankara, Turkey
| | - Raziye Narin
- Clinic of Obstetrics and Gynecology, Numune Training and Research Hospital, Adana, Turkey
| | - Hülya Dede
- Clinic of Obstetrics and Gynecology, Zekai Tahir Burak Training and Research Hospital, Ankara, Turkey
| | - Ömer Kandemir
- Clinic of Obstetrics and Gynecology, Etlik Zübeyde Hanım Training and Research Hospital Ankara, Turkey
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Yoshida M. Mechanical activity of frog esophagus muscle in response to electrical stimulation of intramural nerves. J Smooth Muscle Res 2007; 43:73-84. [PMID: 17598959 DOI: 10.1540/jsmr.43.73] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Microscopic observation of intramural nerves in the frog esophagus, fixed and stained with OsO(4) and ZnI(2), revealed that nerve cell bodies and bundles connecting the nerve cell bodies formed loose and irregular networks. The nerve cell bodies were mostly lying singly in the nerve bundles, with occasional observations of two closely linked nerve cell bodies. Isolated circular and longitudinal segments of esophageal muscle were spontaneously rhythmically contractile, with a frequency of 2.2-3.0 per min. This was not altered by tetrodotoxin (TTX). In longitudinal muscle segments, transmurally applied electrical stimulation produced contractile responses which were not inhibited by atropine or guanethidine, but were reduced in amplitude by TTX, suggesting a nonadrenergic-noncholinergic (NANC) excitatory innervation in the esophagus muscle. In circular muscle segments, transmural application of brief electrical stimulation evoked two types of mechanical response: a biphasic response consisting of an initial relaxation and a following contraction (type I) and a contraction alone (type II). These mechanical responses were not modulated by either atropine or guanethidine. In the type I response, TTX abolished the relaxation component, suggesting that this was produced by non-adrenergic non-cholinergic (NANC) inhibitory nerve excitation. In about half of the type II responses, the amplitude of the contraction was significantly reduced by TTX, suggesting that a part of the contraction was produced by activation of NANC excitatory nerves. Thus, the esophageal smooth muscle of the frog demonstrates myogenic activity, and is innervated by both excitatory and inhibitory NANC nerves.
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Affiliation(s)
- Masahide Yoshida
- Laboratory of Physiology, Faculty of Health and Social Work, Kanagawa University of Human Services, Yokosuka, Japan
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3
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Demirkoprulu N, Cetin M, Bagcivan I, Kaya T, Soydan AS, Karadas B, Cetin A. Comparative relaxant effects of YC-1 and DETA/NO on spontaneous contractions and the levels of cGMP of isolated pregnant rat myometrium. Eur J Pharmacol 2005; 517:240-5. [PMID: 15985262 DOI: 10.1016/j.ejphar.2005.05.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2005] [Revised: 05/12/2005] [Accepted: 05/24/2005] [Indexed: 10/25/2022]
Abstract
This study was designed to compare the effects of YC-1 (3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole), a nitric oxide (NO)-independent soluble guanylate cyclase activator, and diethylenetriamine-NONOate (DETA/NO), a NO donor, on spontaneous contractions and the levels of cyclic GMP (cGMP) of myometrial strips isolated from timed-pregnant rats. Myometrial strips were obtained from timed-pregnant Wistar albino rats (n=10) and were mounted in organ baths and tested for changes in isometric tension in response to YC-1 and DETA/NO. We also evaluated the effect of YC-1 and DETA/NO on the levels of cGMP in myometrial strips obtained from timed-pregnant rat uterine horns (n=20). YC-1 (10(-9)-3x10(-5) M) and DETA/NO (10(-7)-10(-4) M) concentration-dependently decreased the amplitude and frequency of spontaneous contractions of myometrial strips isolated from term-pregnant rats. The inhibitions of the amplitude and frequency of spontaneous contractions by YC-1 and DETA/NO were antagonized with methylene-blue (10(-5) M). Antagonistic effect of methylene-blue (10(-5) M) was more on DETA/NO responses than that of YC-1 (P<0.05). In addition, YC-1-stimulated myometrial strips showed more elevation in myometrial cGMP than that of DETA/NO (P<0.05). We demonstrated that YC-1 and DETA/NO induce relaxations in the amplitude and frequency of spontaneous contractions of myometrial strips with different potencies. We also found that YC-1 and DETA/NO-induced relaxations are associated with significant increases in cGMP. These results might suggest that the relaxant effects of YC-1 and DETA/NO on the rat myometrium could be due to the stimulation of the soluble guanylate cyclase and cGMP may play a role for the maintenance of uterine quiescence during pregnancy.
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Affiliation(s)
- Nihal Demirkoprulu
- Department of Obstetrics and Gynecology, Cumhuriyet University School of Medicine, 58140, Sivas, Turkey
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Buxton ILO. Regulation of uterine function: a biochemical conundrum in the regulation of smooth muscle relaxation. Mol Pharmacol 2004; 65:1051-9. [PMID: 15102932 DOI: 10.1124/mol.65.5.1051] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Premature birth accounts for the majority of fetal morbidity and mortality in the developed world and is disproportionately represented in some populations, such as African Americans in the United States. The costs associated with prematurity are staggering in both monetary and human terms. Present therapeutic approaches for the treatment of labor leading to preterm delivery are inadequate and our understanding of the regulation of myometrial smooth muscle contraction-relaxation is incomplete. The ability of nitric oxide to relax smooth muscle has led to an interest in employing nitric oxide-donors in the treatment of preterm labor. Fundamental differences exist, however, in the regulation of uterine smooth muscle relaxation and that of other smooth muscles and constitute a conundrum in our understanding. We review the evidence that nitric oxide-mediated relaxation of myometrial smooth muscle, unlike vascular or gastrointestinal smooth muscle, is independent of global elevation of cyclic guanosine 5'-monophosphate. Applying our current understanding of microdomain signaling and taking clues from genomic studies of pregnancy, we offer a framework in which to view the apparent conundrum and suggest testable hypotheses of uterine relaxation signaling that can explain the mechanistic distinctions. We propose that understanding these mechanistic distinctions in myometrium will reveal molecular targets that are unique and thus may be explored as therapeutic targets in the development of new uterine smooth muscle-specific tocolytics.
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Affiliation(s)
- Iain L O Buxton
- Department of Pharmacology, University of Nevada School of Medicine, Reno, NV 89557, USA.
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5
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Hendler I, Baum M, Kreiser D, Schiff E, Druzin M, Stevenson DK, Seidman DS. End-tidal breath carbon monoxide measurements are lower in pregnant women with uterine contractions. J Perinatol 2004; 24:275-8. [PMID: 15042112 DOI: 10.1038/sj.jp.7211094] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To compare the levels of end-tidal carbon monoxide (ETCOc) among women with and without uterine contractions in term and preterm pregnancies. STUDY DESIGN In all, 55 nonsmoking healthy pregnant women were enrolled. ETCOc levels were compared among women with contractions (10 preterm and 13 term) and 32 women without contractions (34-41 weeks gestation). RESULTS Maternal age, gravidity and parity were similar among study and control groups. ETCOc levels were significantly lower among women that had uterine contractions (0.99+/-0.38 parts per million (ppm) and 1.15+/-0.34 p.p.m. respectively), compared to women with no contractions (1.70+/-0.52 p.p.m., P<0.002). However, there was no significant difference in the ETCOc levels between women with preterm or term contractions (P=0.48). CONCLUSIONS Low levels of ETCOc are associated with preterm and term uterine contractions.
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Affiliation(s)
- Israel Hendler
- Department of Obstetrics and Gynecology, Sheba Medical Center, Tel-Hashomer, Tel-Aviv University, Tel-Aviv, Israel
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Abstract
BACKGROUND A number of tocolytics have been advocated for the treatment of threatened preterm labour in order to delay delivery. The rationale is that a delay in delivery may be associated with improved neonatal morbidity or mortality. Nitric oxide donors, such as nitroglycerin, have been used to relax the uterus. This review addresses their efficacy, side effects and influence on neonatal outcome. OBJECTIVES To determine whether nitric oxide donors administered in threatened preterm labour are associated with a delay in delivery, adverse side effects or improved neonatal outcome. SEARCH STRATEGY A comprehensive search of the Cochrane Pregnancy and Childbirth Group trials register (March 2002) and the Cochrane Controlled Trials Register (The Cochrane Library, Issue 1, 2002) was undertaken. SELECTION CRITERIA Randomised controlled trials of nitric oxide donors administered for tocolysis. DATA COLLECTION AND ANALYSIS Trial quality assessment and data extraction were done independently by two reviewers. MAIN RESULTS Five randomised controlled trials (466 women) were included. Nitroglycerine was the NO donor used in all these trials. Nitric oxide donors did not delay delivery nor improve neonatal outcome when compared with placebo, no treatment or alternative tocolytics such as ritodrine, albuterol and magnesium sulphate. There was, however, a reduction in number of deliveries less than 37 weeks when compared with alternative tocolytics but the numbers of deliveries before 32 and 34 weeks were not influenced. Side effects (other than headache) were reduced in women who received nitric oxide donors rather than other tocolytics. However, women were significantly more likely to experience headache when NO donors had been used. REVIEWER'S CONCLUSIONS There is currently insufficient evidence to support the routine administration of nitric oxide donors in the treatment of threatened preterm labour.
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Affiliation(s)
- K Duckitt
- Nuffield Department of Obstetrics and Gynaecology, Level 3, Women's Centre, John Radcliffe Hospital, Headington, Oxford, UK, OX3 9DU.
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Cornwell TL, Li J, Sellak H, de Lanerolle P, Rodgers WH, Miller RT, Word RA. Regulation of cyclic guanosine monophosphate-dependent protein kinase in human uterine tissues during the menstrual cycle. Biol Reprod 2001; 64:857-64. [PMID: 11207201 DOI: 10.1095/biolreprod64.3.857] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Contractility of uterine smooth muscle is essential for the cyclic shedding of the endometrial lining and also for expulsion of the fetus during parturition. The nitric oxide (NO)-cGMP signaling pathway is involved in smooth muscle relaxation. The downstream target of this pathway essential for decreasing cytoplasmic calcium and muscle tone is the cGMP-dependent protein kinase (PKG). The present study was undertaken to localize expression of PKG in tissues of the female reproductive tract and to test the hypothesis that uterine smooth muscle PKG levels vary with the human menstrual cycle. Immunohistochemistry was used to localize PKG in myometrium, cervix, and endometrium obtained during proliferative and secretory phases. The PKG was localized to uterine and vascular smooth muscle cells in myometrium, stromal cells in endometrium, and a small percentage of cervical stromal cells. Using Western blot analysis and protein kinase activity assays, the expression of PKG was reduced significantly in progesterone-dominated uteri compared with myometrium from postmenopausal women or women in the proliferative phase. These findings support a role for PKG in the control of uterine and vascular smooth muscle contractility during the menstrual cycle.
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Affiliation(s)
- T L Cornwell
- Department of Pathology, Division of Molecular and Cellular Pathology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0019, USA.
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Affiliation(s)
- M A Ledingham
- Department of Obstetrics and Gynaecology, University of Glasgow
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9
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Vedernikov YP, Syal AS, Okawa T, Jain V, Saade GR, Garfield RE. The role of cyclic nucleotides in the spontaneous contractility and responsiveness to nitric oxide of the rat uterus at midgestation and term. Am J Obstet Gynecol 2000; 182:612-9. [PMID: 10739517 DOI: 10.1067/mob.2000.104203] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVES The aim of this investigation was to study the effects of pharmacologic manipulation of cyclic nucleotide levels on the uterine spontaneous contractile activity and responsiveness to nitric oxide in pregnant rats at midgestation and term. STUDY DESIGN Uterine rings from pregnant rats at midgestation and term were placed in organ chambers for isometric tension recording. Concentration-response curves were obtained for phosphodiesterase and guanylate cyclase inhibitors, membrane-permeable cyclic nucleotide analogs, and forskolin. In addition, the effects of minimal inhibitory concentrations of these agents on the concentration-response relationships for diethylamine nitric oxide (a nitric oxide donor) were studied. RESULTS Nonselective phosphodiesterase inhibitors induced more inhibition of contractions of uterine rings from pregnant rats at term than at midgestation and zaprinast induced less. Inhibitors of guanylate cyclase and membrane-permeable analogs of cyclic guanosine monophosphate were equally effective in tissues from pregnant rats at midgestation and term. All agents attenuated the inhibitory effect of diethylamine nitric oxide at midgestation; however, dibutyryl cyclic adenosine monophosphate and papaverine increased the inhibitory effect of diethylamine nitric oxide in tissues from pregnant animals at term. CONCLUSIONS Cyclic nucleotides modulate both spontaneous and nitric oxide-induced changes in uterine contraction during pregnancy. Application of nonselective inhibitors of phosphodiesterase, as well as membrane-permeable analogs of cyclic adenosine monophosphate, may counteract refractoriness to nitric oxide at term.
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Affiliation(s)
- Y P Vedernikov
- Division of Reproductive Sciences and Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, Galveston, TX 77555-1062, USA
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10
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Bartlett SR, Bennett PR, Campa JS, Dennes WJ, Slater DM, Mann GE, Poston L, Poston R. Expression of nitric oxide synthase isoforms in pregnant human myometrium. J Physiol 1999; 521 Pt 3:705-16. [PMID: 10601500 PMCID: PMC2269695 DOI: 10.1111/j.1469-7793.1999.00705.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
1. Endogenous nitric oxide has been proposed to play a role in the control of myometrial contractility in pregnancy. In this study, the expression, localisation and regulation of nitric oxide synthase (NOS) isoforms have been examined in human pregnant myometrium and cultured human myometrial smooth muscle cells, by immunoblotting, immunohistochemistry and reverse transcription-polymerase chain reaction. 2. Immunoblotting of extracts from freshly isolated myometrial tissue, affinity-enriched for NOS proteins by precipitation with ADP-sepharose, revealed expression of endothelial NOS (eNOS or NOS3) in tissues from preterm, term non-labour and active labour at term. Inducible NOS (iNOS or NOS2) and neuronal NOS (nNOS or NOS1) proteins were not detected at any stage of pregnancy. 3. Immunohistochemical detection showed that expression of eNOS protein was restricted to the endothelium of the myometrial vasculature, with no staining detected in myometrial smooth muscle cells. 4. Messenger RNA for all three NOS isoforms was detected, although iNOS and nNOS mRNAs were detectable only with high cycle number, implying a low copy number. 5. NOS isoforms were not detectable in human myometrial smooth muscle cells cultured from term non-labour pregnancies. Cytokine stimulation of cultured myometrial cells did not induce iNOS expression or nitrite accumulation in the culture medium, although both iNOS protein and nitrite release were detected in the human pulmonary epithelial cell line A549. 6. Levels of eNOS protein and of NOS mRNA expression were not correlated with gestational stage, suggesting that endogenously produced NO is not likely to be a modulator of myometrial tone during human pregnancy.
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Affiliation(s)
- S R Bartlett
- Centre for Cardiovascular Biology and Medicine, GKT Schools of Biomedical Sciences and Medicine, King's College London, UK
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Barber A, Robson SC, Lyall F. Hemoxygenase and nitric oxide synthase do not maintain human uterine quiescence during pregnancy. THE AMERICAN JOURNAL OF PATHOLOGY 1999; 155:831-40. [PMID: 10487841 PMCID: PMC1866893 DOI: 10.1016/s0002-9440(10)65182-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/07/1999] [Indexed: 10/18/2022]
Abstract
The nitric oxide (NO)-cGMP pathway has been proposed as a mechanism for relaxation of myometrium during pregnancy and as a modulator of labor. Carbon monoxide (CO), produced by hemeoxygenases (HO-1 and HO-2), also activates soluble guanylate cyclase to increase cGMP. A recent study reported a large increase in HO-1 and HO-2 proteins during pregnancy, suggesting that the HO-CO pathway may be important in the maintenance of uterine quiescence during pregnancy. In this study we used Western blotting, reverse transcription-polymerase chain reaction, and immunohistochemistry to determine HO-1 and HO-2 expression in nonpregnant, pregnant, and laboring myometrium. Immunolocalization of HO was also compared with endothelial and inducible nitric oxide synthases (eNOS and iNOS). In contrast to HO-1 protein, which was not detected in myometrium, HO-2 protein and mRNA were constitutively expressed, although there were no differences in expression between the groups. eNOS was expressed in endothelial cells but not in myometrial smooth muscle. iNOS protein was not detected in myometrium. These data do not support an up-regulation of HO-1 and HO-2 during pregnancy and are not consistent with a role for NO or a major role for CO in human myometrial quiescence. Our results are also in keeping with HO-2 being an noninducible protein.
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Affiliation(s)
- A Barber
- Maternal and Fetal Medicine Section,(*) Institute of Medical Genetics, Yorkhill, Glasgow Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
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Syal A, Okawa T, Vedernikov Y, Chwalisz K, Saade GR, Garfield RE. Effect of placental tissue on inhibition of uterine contraction by nitric oxide donors. Am J Obstet Gynecol 1999; 181:415-8. [PMID: 10454693 DOI: 10.1016/s0002-9378(99)70571-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
OBJECTIVE Our purpose was to test the hypothesis that placental tissue modulates the effect of nitric oxide on spontaneous uterine contractility in pregnant rats. STUDY DESIGN Rings (approximately 4 mm) of uterus taken from rats on day 14 (midpregnancy, n = 6), day 18 (late pregnancy, n = 4), and day 22 (term, n = 4) of gestation were placed in organ chambers filled with Krebs-bicarbonate buffer bubbled with 5% carbon dioxide in air (37 degrees C, pH approximately 7.4) for isometric tension recording. In some rings a piece of placenta was left attached to the uterine wall. In the other rings the fetuses, placentas, and membranes were removed completely. Change of spontaneous contractions of the rings (percentage change of basal integral activity for 10 minutes) in response to cumulative concentrations of the nitric oxide donors diethylamine-nitric oxide and nitroglycerin (10(-6) mol/L to 10(-4) mol/L) were compared between rings with and without placenta. RESULTS Diethylamine-nitric oxide and nitroglycerin inhibited spontaneous uterine contractions in rings from midpregnancy, in both the absence and the presence of placenta. In rings from midpregnancy, the maximal inhibition of contractions by diethylamine-nitric oxide but not by nitroglycerin was significantly (P <.05) higher in the presence (26.7% +/- 3.5% of basal activity) than in the absence (39. 6% +/- 3.3%) of placenta. Inhibition of contraction by nitric oxide donors in rings from late and term pregnancy was less than in midpregnancy, and the presence of placental tissue did not influence the responses. CONCLUSIONS The presence of placental tissue enhances inhibition of uterine contractility by agents that spontaneously release nitric oxide, such as diethylamine-nitric oxide, but not by nitroglycerin, which requires metabolic transformation for nitric oxide to be released. Refractoriness to nitric oxide near or at term does not depend on the presence or absence of placental tissue.
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Affiliation(s)
- A Syal
- Department of Obstetrics and Gynecology, The University of Texas Medical branch, Glaveston, USA
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Sladek SM, Westerhausen-Larson A, Roberts JM. Endogenous nitric oxide suppresses rat myometrial connexin 43 gap junction protein expression during pregnancy. Biol Reprod 1999; 61:8-13. [PMID: 10377025 DOI: 10.1095/biolreprod61.1.8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Nitric oxide (NO) synthase (NOS) is active in the gravid uterus, and its activity decreases prior to the onset of parturition. We tested the hypothesis that NO helps maintain uterine quiescence by suppressing the expression of genes necessary for parturition. Pregnant rats (18 days gestation) were treated with inducible NOS (iNOS) inhibitor N-iminoethyl-L-lysine (NIL) or endothelial NOS inhibitor nitro-L-arginine methyl ester (L-NAME); 24 h later, uteri were analyzed for myometrial connexin 43 (Cx43) protein by immunoblotting and mRNA by Northern analysis. Myometrial oxytocin receptors (OTR) were measured by radioligand binding, and decidual prostaglandin H synthase (PGHS) protein by immunoblotting. Uterine NOS blockade was verified by NOS activity assay. We found that NIL, but not L-NAME, significantly increased myometrial Cx43 protein to parturitional levels with treatment at 19 but not 17 days gestation. Steady state mRNA concentrations were not changed at 24 h. NOS inhibition did not increase the concentrations of OTR, or PGHS protein, nor did it decrease maternal serum progesterone. We conclude that endogenous uterine NO from iNOS suppresses myometrial Cx43 gap junction protein expression during rat pregnancy. Although the exact mechanism is unknown, an increase of uterine wall stretch due to inhibition of relaxation could account for increased Cx43 gene transcription.
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Affiliation(s)
- S M Sladek
- Magee-Womens Research Institute, Department of Obstetrics, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
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Simpkin JC, Kermani F, Palmer AM, Campa JS, Tribe RM, Linton EA, Poston L. Effects of corticotrophin releasing hormone on contractile activity of myometrium from pregnant women. BRITISH JOURNAL OF OBSTETRICS AND GYNAECOLOGY 1999; 106:439-45. [PMID: 10430194 DOI: 10.1111/j.1471-0528.1999.tb08297.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To determine whether corticotrophin releasing hormone plays a role in the regulation of tone in term nonlabouring human myometrium. SETTING A teaching hospital research laboratory. SAMPLE Thirty-seven women undergoing elective nonlabour caesarean section under regional anaesthesia. METHODS Human corticotrophin releasing hormone (1, 10, 100 nmol/L) was added to strips of term, nonlabouring myometrium mounted in an organ bath, and the effect on spontaneous, oxytocin (1 nmol/L) or prostaglandin F2alpha (100 nmol/L) stimulated contractions determined. Cyclic adenosine monophosphate (cAMP) content of the tissue was also determined by enzyme immunoassay. RESULTS Corticotrophin releasing hormone did not affect myometrial tension development in any of the experimental protocols. cAMP increased transiently after addition of corticotrophin releasing hormone (166.7 +/- 12.7% at 1 minute) but this was not reflected by any change in tension. CONCLUSIONS This study suggests that despite high maternal plasma concentrations of corticotrophin releasing hormone in pregnancy at term, this peptide is unlikely to play a direct role in the control of myometrial contractility in nonlabouring myometrium.
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Affiliation(s)
- J C Simpkin
- Fetal Health Research Group, United Medical and Dental Schools, London, UK
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Dennes WJ, Slater DM, Poston L, Bennett PR. Myometrial nitric oxide synthase messenger ribonucleic acid expression does not change throughout gestation or with the onset of labor. Am J Obstet Gynecol 1999; 180:387-92. [PMID: 9988806 DOI: 10.1016/s0002-9378(99)70219-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The purposes of this study were to examine expression of nitric oxide synthase isoforms in human myometrium and to determine any changes in expression with gestational age and with the onset of labor at term. STUDY DESIGN Myometrial samples were collected from patients undergoing cesarean delivery at term before and after the onset of labor (n = 17) and throughout gestation (n = 13). Expressions of inducible, calcium-independent nitric oxide synthase and constitutive, calcium-dependent endothelial nitric oxide synthase were determined by semiquantitative reverse transcriptase-polymerase chain reaction. RESULTS Messenger ribonucleic acid for inducible, calcium-independent nitric oxide synthase and constitutive, calcium-dependent endothelial nitric oxide synthase is expressed in human myometrium at term and throughout the second and third trimesters. Levels of messenger ribonucleic acid for both inducible, calcium-independent nitric oxide synthase and constitutive, calcium-dependent endothelial nitric oxide synthase do not change with either gestational age or the onset of labor. CONCLUSION Changes in myometrial nitric oxide synthase expression and thus of levels of endogenous nitric oxide are unlikely to be directly involved in myometrial quiescence or the onset of human parturition.
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Affiliation(s)
- W J Dennes
- Division of Paediatrics, Imperial College School of Medicine, Queen Charlotte's and Chelsea Hospital, London, United Kingdom
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Egberts J, van den Bosch N, Brand R. Nitric oxide metabolites, cyclic guanosine 3,5 monophosphate and dimethylarginines during and after uncomplicated pregnancies: a longitudinal study. Eur J Obstet Gynecol Reprod Biol 1999; 82:35-40. [PMID: 10192482 DOI: 10.1016/s0301-2115(98)00184-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
OBJECTIVE In cross-sectional studies, the variability between women may mask or deny gestational changes, related to the nitric oxide-cyclic GMP system. Therefore, we analyzed longitudinally as markers of this system, the urinary levels of nitrite+nitrate (NOx), cyclic guanosine 3',5' monophosphate (cGMP) and of the inhibitor of nitric oxide synthase, dimethylarginine (DMA). STUDY DESIGN Late-afternoon urine samples were obtained from 20 women with uncomplicated pregnancies and nine non-pregnant women. Creatinine concentrations (mol) were determined with the Jaffé reagent and NOx (mmol) with the Griess reagent after reduction of nitrate. cGMP (micromol) was determined in an enzyme immunoassay and DMA (mmol) after solid-phase extraction and liquid chromatography. Trend analyses and (paired) t-tests were done for detection of time-related differences. RESULTS The NOx/creatinine (mmol/mol) ratios of the non pregnant women (63.8+/-18.8, S.D.) did not differ from those of the pregnant women at the onset of pregnancy (70.5+/-36.4). Over the entire pregnancy period these ratios declined significantly (P<0.001) and lower values were found at the end of gestation and after birth (49.6+/-22.4). The cGMP/creatinine (micromol/mol) and DMA/creatinine ratios (mmol/mol) changed parabolically (P<0.001). The maxima of 68.0+/-19.9 and of 4.95+/-1.01 were found at week 20 and 16, respectively. These ratios declined to 45.2+/-17.7 and to 4.03+/-0.83 at the end of gestation but not further during parturition (39.6+/-17.2 and 4.01+/-1.90). The lowest cGMP/creatinine ratios occurred one month after birth (27.4+/-15.7) while in the non-pregnant women the value was 15.3+/-6.2 microM/M. The lowest DMA/creatinine ratios, measured one month after birth (3.41+/-1.28 mmol/mol) were similar to those of the non-pregnant women (3.75+/-0.39 mmol/mol). Positive instead of negative relationships were found between the DMA results and those of the cGMP (P<0.001) and NOx determinations (P<0.05). CONCLUSIONS (1) The gestational changes of the urinary NOx/creatinine and especially of the GMP/creatinine ratio reflect most likely changes in vascular resistance. (2) Because of the variability of the results between but also within women, these ratios are useless to monitor supposed changes in NO production during parturition.
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Affiliation(s)
- J Egberts
- Department of Obstetrics, Gynecology, Leiden University Medical Center, Netherlands.
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Modzelewska B, Sipowicz MA, Saavedra JE, Keefer LK, Kostrzewska A. Involvement of K+ATP channels in nitric oxide-induced inhibition of spontaneous contractile activity of the nonpregnant human myometrium. Biochem Biophys Res Commun 1998; 253:653-7. [PMID: 9918782 DOI: 10.1006/bbrc.1998.9844] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nitric oxide (NO), an important endogenous substance, is known to be a strong relaxant of smooth muscle, including myometrium. It has been postulated that the relaxing effect of NO on smooth muscle is achieved by the stimulation of soluble guanylyl cyclase, which leads to an increase in the cyclic guanosine 3',5'-monophosphate (cGMP) levels and hyperpolarization of the cellular membrane. The aim of our study was to investigate the involvement of K+ATP channels in the mechanism of cGMP-independent nitric oxide-induced inhibition of contractile activity of the nonpregnant human myometrium, obtained at hysterectomy. Nitric oxide's influence on contractile activity was recorded in the presence of methylene blue and glybenclamide, blockers of soluble guanylyl cyclase and K+ATP channels, respectively. Nitric oxide, generated by the NO donor DEA/NO, caused a dose-dependent inhibition of the spontaneous contractile activity of human nonpregnant myometrium. Preincubation with methylene blue (5 microM) did not prevent NO-induced relaxation of uterine strips, while 1.5 microM glybenclamide blocked this effect. Our results indicate that nitric oxide relaxes human non-pregnant uterus through K+ATP channels, independent of the cGMP pathway.
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Affiliation(s)
- B Modzelewska
- Department of Biophysics, Medical School, Bialystok, Poland
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20
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Bocking AD. Preterm labour: recent advances in understanding of pathophysiology, diagnosis and management. Curr Opin Obstet Gynecol 1998; 10:151-6. [PMID: 9551311 DOI: 10.1097/00001703-199804000-00012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Recent advances in the importance of sociodemographic factors, including maternal stress, as well as potential predictors of preterm birth are reviewed. The recommended role of adjunctive antibiotic therapy, in women with preterm premature rupture of the membranes but not in women with intact membranes, is discussed. The possibility of causes other than those related to infection in preterm rupture of the membranes is raised, and new information regarding the use of glucocorticoids and tocolytics is presented. Despite steady improvements in neonatal survival and morbidity rates over the past decade primarily as a result of improved neonatal care, there has been no corresponding decrease in the incidence of preterm birth. An improved understanding of the pathophysiology and diagnosis of preterm birth remains one of the greatest challenges in obstetric care in this decade.
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Affiliation(s)
- A D Bocking
- Department of Obstetrics and Gynaecology, St. Joseph's Health Centre, London, Ontario, Canada
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Acevedo CH, Ahmed A. Hemeoxygenase-1 inhibits human myometrial contractility via carbon monoxide and is upregulated by progesterone during pregnancy. J Clin Invest 1998; 101:949-55. [PMID: 9486963 PMCID: PMC508644 DOI: 10.1172/jci927] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Nitric oxide was proposed as an endogenous inhibitor of myometrial contractility during pregnancy. Carbon monoxide (CO) like nitric oxide increases cGMP and is generated during the degradation of heme to biliverdin IX by hemeoxygenases (HO). Here we report that the expression of both HO-1 (inducible) and HO-2 (constitutive) were > 15-fold higher in pregnant myometrium compared to nonpregnant myometrium (n = 4, P < 0.001, P < 0.005, respectively). Moreover, the activation of the HO-CO pathway by the HO inducer, hemin (10 microM), completely inhibited spontaneous contractility (n = 3). Oxytocin-stimulated contractions (n = 5) were also significantly reduced (P < 0.05) in myometrial strips mounted for isometric recording under 2 g tension in Krebs solution. Reverse transcription-PCR analysis revealed that mRNA encoding HO-1 and HO-2 was undetected in explant cultures of nonlaboring pregnant myometrium under basal conditions, however, exposure to progesterone, but not estradiol-17beta, induced the expression of HO-1 and HO-2 mRNAs. Progesterone also significantly induced HO-1 protein synthesis (n = 4, P < 0.001) while estradiol-17beta had no effect (n = 4). In term (37-42-wk gestation) nonlaboring myometrial explants, CO production was stimulated by progesterone (10(-6) M) (n = 2) and hemin (10 microM) (n = 3) after 2 h of incubation and the effect of hemin was inhibited by 1 h of preincubation with the HO inhibitor tin protoporphyrin IX (20 microM). This study clearly demonstrates the expression of HO in the human myometrium and shows that its induction produces CO that limits uterine contractility in pregnant myometrium indicating a role for the HO-CO-cGMP pathway in the maintenance of the quiescent state of the uterus during pregnancy.
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Affiliation(s)
- C H Acevedo
- Reproductive Physiopathology Group, Department of Obstetrics and Gynaecology, Birmingham Women's Hospital, The University of Birmingham, Edgbaston, Birmingham, B15 2TG, United Kingdom
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Word RA, Cornwell TL. Regulation of cGMP-induced relaxation and cGMP-dependent protein kinase in rat myometrium during pregnancy. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:C748-56. [PMID: 9530107 DOI: 10.1152/ajpcell.1998.274.3.c748] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Increases in guanosine 3',5'-cyclic monophosphate (cGMP) induced by nitric oxide (NO), nitrovasodilators, and atrial peptides correlate with relaxation of vascular smooth muscle. Relaxation of myometrial smooth muscle by increases in cGMP, however, has required unusually high concentrations of the cyclic nucleotide. We tested the hypothesis that the sensitivity of myometrium to relaxation by cGMP is increased during pregnancy. Aortic smooth muscle was more sensitive to relaxation by cGMP than myometrial tissues, and, contrary to our hypothesis, myometrium from pregnant rats was least sensitive. Although levels of cGMP were elevated after treatment with the NO donor, S-nitroso-N-acetylpenicillamine, relaxation of myometrial tissues obtained from pregnant rats occurred only at extraordinarily high concentrations. The levels of cGMP-dependent protein kinase (PKG) were significantly decreased in myometrium from pregnant rats compared with myometrium from nonpregnant cycling animals or aortic smooth muscle. Administration of estradiol to ovariectomized rats increased myometrial PKG expression, and progesterone antagonized this response. We conclude that 1) myometrial tissues from pregnant rats are not sensitive to relaxation by cGMP and 2) this insensitivity to cGMP is accompanied by progesterone-mediated decreases in the level of PKG expression.
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Affiliation(s)
- R A Word
- Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas 75235-9032, USA
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Eis AL, Brockman DE, Myatt L. Immunolocalization of the inducible nitric oxide synthase isoform in human fetal membranes. Am J Reprod Immunol 1997; 38:289-94. [PMID: 9352017 DOI: 10.1111/j.1600-0897.1997.tb00517.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
PROBLEM Nitric oxide (NO) synthesized by fetal membranes may protect the fetus from maternal infection or immune challenge or have a tocolytic effect on myometrium. The sites of synthesis and enzymes responsible for NO production in human fetal membranes remain unidentified. METHOD OF STUDY Fetal membranes were obtained from four groups of patients: term (> 37 weeks gestation) or preterm (< 37 weeks gestation), both either in labor or not in labor. Frozen sections of membrane rolls were immunostained for inducible (iNOS) and endothelial (eNOS) nitric oxide synthase isoforms and the monocyte/macrophage marker CD14. RESULTS Positive iNOS immunostaining was found in fibroblasts of amnionic and chorionic mesenchyme and in decidual macrophages identified by CD14 from all four groups of tissues. No iNOS immunostaining was seen in amnion epithelium or chorion trophoblast. Very intense iNOS staining was seen with evidence of monocyte/macrophage invasion of membranes. eNOS immunostaining was only found in decidual vascular endothelium. CONCLUSIONS Constitutive expression of iNOS in decidual macrophages and fetal membrane fibroblasts may form an immune barrier against maternal insult. In chorioamnionitis, macrophage recruitment and NO expression may be part of the maternal immune response.
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Affiliation(s)
- A L Eis
- Department of Obstetrics and Gynecology, University of Cincinnati College of Medicine, OH 45267-0526, USA
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Buhimschi C, Buhimschi I, Yallampalli C, Chwalisz K, Garfield RE. Contrasting effects of diethylenetriamine-nitric oxide, a spontaneously releasing nitric oxide donor, on pregnant rat uterine contractility in vitro versus in vivo. Am J Obstet Gynecol 1997; 177:690-701. [PMID: 9322644 DOI: 10.1016/s0002-9378(97)70166-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE The aim of the study was to investigate the in vitro (on tension) and in vivo (on intrauterine pressure) effects of a spontaneously releasing nitric oxide adduct, diethylenetriamine-nitric oxide, on rat uterine contractility. STUDY DESIGN Contractile responses to the nitric oxide donor diethylenetriamine-nitric oxide on isometric tension of rat uterine strips (in vitro) and on intrauterine pressure (in vivo) in anesthetized and conscious animals were quantified at late gestation and during preterm and term labor. Preterm labor was induced with the administration of a single injection of the antiprogestin onapristone (10 mg). All control animals were injected with diethylenetriamine, the parent compound, without nitric oxide. RESULTS The nitric oxide donor diethylenetriamine-nitric oxide relaxes rat uterine tissues when given in vitro during gestation (median effective dose 0.30 +/- 0.09 mmol/L) but fails to have an effect on uterine tissues from laboring term and preterm animals in the muscle bath. Intraperitoneal injection of the nitric oxide adduct in doses of 5 mg and 50 mg produced a significant and sustained decrease in intrauterine pressure in both delivering and nondelivering animals compared with intrauterine pressure values before administration. Analysis of intrauterine pressure levels at different time frames (before injection, immediately after injection, and after 30, 60, and 90 minutes) in anesthetized rats between days 19 and 21 of gestation shows that the dose of 5 mg diethylenetriamine-nitric oxide significantly (p < 0.05) decreased contractility starling at 30 minutes after administration. Similarly, during labor diethylenetriamine-nitric oxide (5 mg intraperitoneally) decreased contractility (p < 0.05) but only starting at 60 minutes after injection. However, with the dose of 50 mg diethylenetriamine-nitric oxide contractility was reduced 30 minutes (p < 0.05) after treatment during pregnancy (days 19 to 21). The same dose of diethylenetriamine-nitric oxide produced a greater relaxation immediately after intraperitoneal injection (p < 0.05) in the laboring group. Diethylenetriamine-nitric oxide (50 mg) also induced an earlier onset and greater relaxation in animals delivering preterm compared with nondelivering animals at the same stage of gestation. The intrauterine pressure maintained constant contractility levels throughout the 100-minute recording period in the control groups of anesthetized and conscious animals that were injected with diethylenetriamine at the equivalent doses. In the preterm laboring group the effects were similar in both anesthetized and conscious animals. CONCLUSION Although in vitro studies of uterine muscle show decreased inhibitory responses to nitric oxide donors during spontaneous term labor and preterm labor compared with tissues collected during late pregnancy (day 19), studies in vivo demonstrate that nitric oxide donors can decrease uterine contractility even more effectively during delivery. The results suggest that nitric oxide donors may act indirectly or that the fetal-placental unit increases the availability of nitric oxide in vivo. Therefore, despite what in vitro studies alone suggest, nitric oxide donor drugs may be very effective in suppressing either term or preterm labor.
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Affiliation(s)
- C Buhimschi
- Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston 77555-1062, USA
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