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Ansari JR, Yarmosh A, Michel G, Lyell D, Hedlin H, Cornfield DN, Carvalho B, Bateman BT. Intravenous Calcium to Decrease Blood Loss During Intrapartum Cesarean Delivery: A Randomized Controlled Trial. Obstet Gynecol 2024; 143:104-112. [PMID: 37917943 DOI: 10.1097/aog.0000000000005441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 09/21/2023] [Indexed: 11/04/2023]
Abstract
OBJECTIVE To evaluate whether prophylactic administration of 1 g of intravenous calcium chloride after cord clamping reduces blood loss from uterine atony during intrapartum cesarean delivery. METHODS This single-center, block-randomized, placebo-controlled, double-blind superiority trial compared the effects of 1 g intravenous calcium chloride with those of saline placebo control on blood loss at cesarean delivery. Parturients at 34 or more weeks of gestation requiring intrapartum cesarean delivery after oxytocin exposure in labor were enrolled. Calcium or saline placebo was infused over 10 minutes beginning 1 minute after umbilical cord clamping in addition to standard care with oxytocin. The primary outcome was quantitative blood loss, analyzed by inverse Gaussian regression. Planned subgroup analysis excluded nonatonic bleeding, such as hysterotomy extension, arterial bleeding, and occult placenta accreta. We planned to enroll 120 patients to show a 200-mL reduction in quantitative blood loss in planned subgroup analysis, assuming up to 40% incidence of nonatonic bleeding (80% power, α<0.05). RESULTS From April 2022 through March 2023, 828 laboring parturients provided consent and 120 participants were enrolled. Median blood loss was 840 mL in patients allocated to calcium chloride (n=60) and 1,051 mL in patients allocated to placebo (n=60), which was not statistically different (mean reduction 211 mL, 95% CI -33 to 410). In the planned subgroup analysis (n=39 calcium and n=40 placebo), excluding cases of surgeon-documented nonatonic bleeding, calcium reduced quantitative blood loss by 356 mL (95% CI 159-515). Rates of reported side effects were similar between the two groups (38% calcium vs 42% placebo). CONCLUSION Prophylactic intravenous calcium chloride administered during intrapartum cesarean delivery after umbilical cord clamping did not significantly reduce blood loss in the primary analysis. However, in the planned subgroup analysis, calcium infusion significantly reduced blood loss by approximately 350 mL. These data suggest that this inexpensive and shelf-stable medication warrants future study as a novel treatment strategy to decrease postpartum hemorrhage, the leading global cause of maternal morbidity and mortality. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov , NCT05027048.
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Affiliation(s)
- Jessica R Ansari
- Department of Anesthesiology, Perioperative and Pain Medicine, the Department of Obstetrics and Gynecology, the Quantitative Sciences Unit, Department of Medicine, and the Department of Pediatrics, Stanford University, Stanford, California
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Riaposova L, Kim SH, Hanyaloglu AC, Sykes L, MacIntyre DA, Bennett PR, Terzidou V. Prostaglandin F2α requires activation of calcium-dependent signalling to trigger inflammation in human myometrium. Front Endocrinol (Lausanne) 2023; 14:1150125. [PMID: 37547305 PMCID: PMC10400332 DOI: 10.3389/fendo.2023.1150125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 06/06/2023] [Indexed: 08/08/2023] Open
Abstract
Introduction Preterm birth is one of the major causes of neonatal morbidity and mortality across the world. Both term and preterm labour are preceded by inflammatory activation in uterine tissues. This includes increased leukocyte infiltration, and subsequent increase in chemokine and cytokine levels, activation of pro-inflammatory transcription factors as NF-κB and increased prostaglandin synthesis. Prostaglandin F2α (PGF2α) is one of the myometrial activators and stimulators. Methods Here we investigated the role of PGF2α in pro-inflammatory signalling pathways in human myometrial cells isolated from term non-labouring uterine tissue. Primary myometrial cells were treated with G protein inhibitors, calcium chelators and/or PGF2α. Nuclear extracts were analysed by TranSignal cAMP/Calcium Protein/DNA Array. Whole cell protein lysates were analysed by Western blotting. mRNA levels of target genes were analysed by RT-PCR. Results The results show that PGF2α increases inflammation in myometrial cells through increased activation of NF-κB and MAP kinases and increased expression of COX-2. PGF2α was found to activate several calcium/cAMP-dependent transcription factors, such as CREB and C/EBP-β. mRNA levels of NF-κB-regulated cytokines and chemokines were also elevated with PGF2α stimulation. We have shown that the increase in PGF2α-mediated COX-2 expression in myometrial cells requires coupling of the FP receptor to both Gαq and Gαi proteins. Additionally, PGF2α-induced calcium response was also mediated through Gαq and Gαi coupling. Discussion In summary, our findings suggest that PGF2α-induced inflammation in myometrial cells involves activation of several transcription factors - NF-κB, MAP kinases, CREB and C/EBP-β. Our results indicate that the FP receptor signals via Gαq and Gαi coupling in myometrium. This work provides insight into PGF2α pro-inflammatory signalling in term myometrium prior to the onset of labour and suggests that PGF2α signalling pathways could be a potential target for management of preterm labour.
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Affiliation(s)
- Lucia Riaposova
- Parturition Research Group, Institute of Reproductive and Developmental Biology, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
- The March of Dimes European Prematurity Research Centre at Imperial College London, London, United Kingdom
| | - Sung Hye Kim
- Parturition Research Group, Institute of Reproductive and Developmental Biology, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
- The March of Dimes European Prematurity Research Centre at Imperial College London, London, United Kingdom
| | - Aylin C. Hanyaloglu
- Parturition Research Group, Institute of Reproductive and Developmental Biology, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Lynne Sykes
- Parturition Research Group, Institute of Reproductive and Developmental Biology, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
- The March of Dimes European Prematurity Research Centre at Imperial College London, London, United Kingdom
- The Parasol Foundation Centre for Women’s Health and Cancer Research, St Mary’s Hospital, Imperial College Healthcare National Health Service (NHS) Trust, London, United Kingdom
| | - David A. MacIntyre
- Parturition Research Group, Institute of Reproductive and Developmental Biology, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
- The March of Dimes European Prematurity Research Centre at Imperial College London, London, United Kingdom
| | - Phillip R. Bennett
- Parturition Research Group, Institute of Reproductive and Developmental Biology, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
- The March of Dimes European Prematurity Research Centre at Imperial College London, London, United Kingdom
| | - Vasso Terzidou
- Parturition Research Group, Institute of Reproductive and Developmental Biology, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
- The March of Dimes European Prematurity Research Centre at Imperial College London, London, United Kingdom
- Department of Obstetrics & Gynaecology, Chelsea and Westminster Hospital National Health Service (NHS) Trust, London, United Kingdom
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Ansari JR, Kalariya N, Carvalho B, Flood P, Guo N, Riley E. Calcium chloride for the prevention of uterine atony during cesarean delivery: A pilot randomized controlled trial and pharmacokinetic study. J Clin Anesth 2022; 80:110796. [PMID: 35447502 DOI: 10.1016/j.jclinane.2022.110796] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 03/23/2022] [Accepted: 03/25/2022] [Indexed: 11/30/2022]
Abstract
STUDY OBJECTIVE To assess the feasibility, patient tolerance, pharmacokinetics, and potential effectiveness of a randomized controlled trial protocol investigating intravenous calcium chloride for the prevention of uterine atony during cesarean delivery. DESIGN Double-blind, randomized controlled pilot trial with nested population pharmacokinetic analysis. SETTING This study was performed at Lucile Packard Children's Hospital, from August 2018 to September 2019. PATIENTS Forty patients with at least two risk factors for uterine atony at the time of cesarean delivery. INTERVENTIONS One gram of intravenous calcium chloride (n = 20 patients) or a saline placebo control (n = 20 patients), in addition to standard care with oxytocin, upon umbilical cord clamping. MEASUREMENTS The primary efficacy-related outcome was the presence of uterine atony defined as the use of a second-line uterotonic medication, surgical interventions for atony, or hemorrhage with blood loss >1000 mL. Blood loss, uterine tone numerical rating scores, serial venous blood calcium levels, hemodynamics, and potential side effects were also assessed. MAIN RESULTS The study protocol proved feasible. The incidence of atony was 20% in parturients who received calcium compared to 50% in the placebo group (relative risk 0.38, P = 0.07, 95% CI 0.15-1.07, NNT 3.3). Calcium recipients tolerated the drug infusion well, with no adverse events and an equal incidence of potential side effects in the calcium and placebo groups. Ionized calcium concentration rose significantly in all patients who received calcium infusion, from baseline 1.18 mmol/L to peak levels 1.50-1.60 mmol/L. One-compartment population pharmacokinetics established clearance of 0.93 (95% CI 0.63-1.52) L/min and volume of distribution 76 (95% CI 49-94) L. CONCLUSIONS In this pilot study, investigators found that intravenous calcium chloride was well-tolerated by the 20 patients assigned to receive the study drug and may be effective in prevention of uterine atony. A 1-g dose was sufficient to substantially increase calcium levels without any critically elevated lab values or concern for adverse side effects. These encouraging findings warrant further investigation of calcium as a novel agent to prevent uterine atony with an adequately powered clinical trial. Clinical trial registry NCT03867383 https://clinicaltrials.gov/ct2/show/NCT03867383.
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Affiliation(s)
- Jessica R Ansari
- Stanford University, Stanford, CA 94305, United States of America.
| | - Neil Kalariya
- Virginia Mason Medical Center, Seattle, WA 98101, United States of America
| | - Brendan Carvalho
- Stanford University, Stanford, CA 94305, United States of America
| | - Pamela Flood
- Stanford University, Stanford, CA 94305, United States of America
| | - Nan Guo
- Stanford University, Stanford, CA 94305, United States of America
| | - Edward Riley
- Stanford University, Stanford, CA 94305, United States of America
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Purohit R, Bera AK. Pannexin 1 plays a pro-survival role by attenuating P2X7 receptor-mediated Ca 2+ influx. Cell Calcium 2021; 99:102458. [PMID: 34479067 DOI: 10.1016/j.ceca.2021.102458] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 07/27/2021] [Accepted: 08/16/2021] [Indexed: 10/20/2022]
Abstract
Extracellular ATP works as an autocrine and/or paracrine signaling molecule by activating plasma membrane-localized purinergic receptors. Stimulation of purinergic P2X7 receptor (P2X7R) increases cytosolic Ca2+ ([Ca2+]c), which in turn activates Pannexin 1 (Panx1) channel. In earlier studies, Panx1 and P2X7R have been shown to interact physically. Also, both the channels have been implicated in similar pathophysiological processes. In this study, we investigated the effect of Panx1 on P2X7R-mediated Ca2+influx. Panx1 attenuated P2X7R-mediated [Ca2+]c rise in CHO-K1 and HEK-293 cells. [Ca2+]c rise was higher in Panx1 knockdown astrocytes. The inhibitory effect was unaffected in the presence of Panx1 blocker, carbenoxolone. The region between 350th and 386th amino acid residues in the carboxyl terminus (CT) of Panx1 was found to be crucial for inhibiting P2X7R. Like full-length Panx1, the CT (350th to 426th amino acids) alone was able to attenuate the [Ca2+]c rise. Further, CT prevented cell death caused by P2X7R overactivation. Based on our results, we propose a novel pro-survival role of Panx1 exerted by modulating P2X7R.
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Affiliation(s)
- Rutambhara Purohit
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600 036, India
| | - Amal Kanti Bera
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600 036, India.
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Calcium signaling cascades differentially regulate PGF 2α-induced myometrial contractions in water buffaloes (Bubalus bubalis). Naunyn Schmiedebergs Arch Pharmacol 2021; 394:1651-1664. [PMID: 33884445 DOI: 10.1007/s00210-021-02084-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 03/30/2021] [Indexed: 10/21/2022]
Abstract
This study unravels the differential involvement of calcium signaling pathway(s) in PGF2α-induced contractions in myometrium of nonpregnant (NP) and pregnant buffaloes. Compared to the myometrium of pregnant animals, myometrium of NP buffaloes was more sensitive to PGF2α as manifested by changes in mean integral tension (MIT) and tonicity. In the presence of nifedipine, myometrial contraction to PGF2α was significantly attenuated in both NP and pregnant uteri; however, mibefradil and NNC 55-0396 produced inhibitory effects only in uterus of pregnant animals, thus suggesting the role of extracellular Ca2+ influx through nifedipine-sensitive L-type Ca2+-channels both in NP and pregnant, but T-type Ca2+ channels seem to play a role only during pregnancy. Entry of extracellular Ca2+ is triggered by enhanced functional involvement of Pyr3-sensitive TRPC3 channels and Rho-kinase pathways as evidenced by a significant rightward shift of the concentration-response curve of PGF2α in the presence of Pyr3 and Y-27632 in NP myometrium. But significant down-expressions of TRPC3 and Rho-A proteins during pregnancy apparently facilitate uterine quiescence. In the presence of Ca2+-free solution and cyclopiazonic acid (SERCA blocker), feeble contraction to PGF2α was observed in both NP and pregnant myometrium which suggests minor role of intracellular source of Ca2+ in mediating PGF2α-induced contractions in these tissues.
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Karakhim SO, Shlykov SG, Babich LG, Sinko DV. Analysis of decay kinetics of the cytosolic calcium transient induced by oxytocin in rat myometrium smooth muscle cells. J Muscle Res Cell Motil 2021; 42:117-127. [PMID: 33590444 DOI: 10.1007/s10974-021-09598-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Accepted: 01/30/2021] [Indexed: 10/22/2022]
Abstract
The method of kinetic analysis of the relaxation phase of the mechanical response of the smooth muscle previously proposed by Burdyga and Kosterin was applied to study the dynamics of the decay of oxytocin-induced calcium transients in cytosol of the rat myometrium smooth muscle cell detected by a fluorescence signal generated by a calcium-sensitive probe fluo-4 using a laser scanning confocal microscope. The experimental data were well linearized in the coordinates ln [(Fm - F)/F] vs lnt (F and Fm are the current fluorescence intensity of the calcium probe and the fluorescence intensity at the maximum of the calcium transient, respectively, while t is the time). The empirical parameters n and τ were determined by which the maximal normalized relaxation rate Vn was calculated for five different ROIs (regions of interest) in the myocyte cytosol. It proved to be almost the same for all ROIs. The maximal normalized relaxation rate calculated from the fluorescence intensity was always lower than that calculated from the corresponding calcium concentration, i.e. the cytosolic Ca2+ concentration in the relaxation phase decreases faster than the corresponding fluorescence intensity. The value of the maximal normalized relaxation rate calculated both from the fluorescence intensity and from the force of oxytocin-induced contractions of isolated rat uterus longitudinal smooth muscles (according to Tsymbalyuk and Kosterin) was exactly the same. This indicates that in the relaxation phase, the decreasing curves of both the fluorescence intensity and the contraction forces coincide.
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Affiliation(s)
- S O Karakhim
- Palladin Institute of Biochemistry of the National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kyiv, 01054, Ukraine.
| | - S G Shlykov
- Palladin Institute of Biochemistry of the National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kyiv, 01054, Ukraine
| | - L G Babich
- Palladin Institute of Biochemistry of the National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kyiv, 01054, Ukraine
| | - D V Sinko
- Taras Shevchenko Kyiv National University, Educational-Scientific Center "Biology and Medicine Institute", 64/13 Volodymyrska Street, Kyiv, 01601, Ukraine
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Munoz-Perez VM, Ortiz MI, Gerardo-Munoz LS, Carino-Cortes R, Salas-Casas A. Tocolytic effect of the monoterpenic phenol isomer, carvacrol, on the pregnant rat uterus. CHINESE J PHYSIOL 2020; 63:204-210. [PMID: 33109786 DOI: 10.4103/cjp.cjp_56_20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Despite the wide application of carvacrol (CAR) in different biological and medical areas, there is still insufficient electrophysiological data on the mechanisms of action of CAR, particularly in the pregnant uterine function. The aim of this study was to evaluate the in vitro tocolytic effect of CAR on the contractility of isolated pregnant rat uterus in the presence of a calcium channel antagonist (nifedipine) and a cyclooxygenase inhibitor (indomethacin). The uteri were isolated from pregnant Wistar rats at 16-18 days of pregnancy and suspended in an isolated organ bath chamber containing a Ringer's physiological solution and aerated with 95% O2and 5% CO2. Samples were used in functional tests to evaluate the inhibitory effect of CAR at increasing concentrations on the rhythmic spontaneous, oxytocin-induced phasic, K+-induced tonic, and Ca2+-induced contractions. The differences in inhibitory concentration-50 and Emaxamong the compounds were determined using the one-way ANOVA followed by a post hoc Student-Newman-Keuls or Bonferroni test, in all casesP < 0.05 was considered statistically significant. Nifedipine was used as positive controls where required. CAR caused a significant concentration-dependent inhibition of the uterine contractions induced by the pharmaco- and electro-mechanic stimuli. We showed that the inhibitory effects of CAR depends on the type of muscle contraction stimuli, and that it acts stronger in spontaneous rhythmic activity and in contractions of isolated rat uterus induced by Ca2+. Nifedipine was more potent than CAR and indomethacin on the uterine contractility (P < 0.05), but none of them was more effective than nifedipine. Therefore, the tocolytic effect induced by CAR was associated with the blockade of the calcium channels in the pregnant rat uterus. This property placed CAR as a potentially safe and effective adjuvant agent in cases of preterm labor, an area of pharmacological treatment that requires urgent improvement.
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Affiliation(s)
- Victor Manuel Munoz-Perez
- Department of Pharmacology, Academic Area of Medicine, Institute of Health Sciences, Autonomous University of the State of Hidalgo, México
| | - Mario I Ortiz
- Department of Pharmacology, Academic Area of Medicine, Institute of Health Sciences, Autonomous University of the State of Hidalgo, México
| | - Lilian S Gerardo-Munoz
- Department of Pharmacology, Academic Area of Medicine, Institute of Health Sciences, Autonomous University of the State of Hidalgo, México
| | - Raquel Carino-Cortes
- Department of Pharmacology, Academic Area of Medicine, Institute of Health Sciences, Autonomous University of the State of Hidalgo, México
| | - Andrés Salas-Casas
- Department of Geriatrics, Academic Area of Gerontology, Institute of Health Sciences, Autonomous University of the State of Hidalgo, México
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Wray S, Arrowsmith S. Uterine Excitability and Ion Channels and Their Changes with Gestation and Hormonal Environment. Annu Rev Physiol 2020; 83:331-357. [PMID: 33158376 DOI: 10.1146/annurev-physiol-032420-035509] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We address advances in the understanding of myometrial physiology, focusing on excitation and the effects of gestation on ion channels and their relevance to labor. This review moves through pioneering studies to exciting new findings. We begin with the myometrium and its myocytes and describe how excitation might initiate and spread in this myogenic smooth muscle. We then review each of the ion channels in the myometrium: L- and T-type Ca2+ channels, KATP (Kir6) channels, voltage-dependent K channels (Kv4, Kv7, and Kv11), twin-pore domain K channels (TASK, TREK), inward rectifier Kir7.1, Ca2+-activated K+ channels with large (KCNMA1, Slo1), small (KCNN1-3), and intermediate (KCNN4) conductance, Na-activated K channels (Slo2), voltage-gated (SCN) Na+ and Na+ leak channels, nonselective (NALCN) channels, the Na K-ATPase, and hyperpolarization-activated cation channels. We finish by assessing how three key hormones- oxytocin, estrogen, and progesterone-modulate and integrate excitability throughout gestation.
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Affiliation(s)
- Susan Wray
- Department of Women's and Children's Health, University of Liverpool, Liverpool L69 3BX, United Kingdom;
| | - Sarah Arrowsmith
- Department of Women's and Children's Health, University of Liverpool, Liverpool L69 3BX, United Kingdom;
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Gestational exposures to organophosphorus insecticides: From acute poisoning to developmental neurotoxicity. Neuropharmacology 2020; 180:108271. [PMID: 32814088 DOI: 10.1016/j.neuropharm.2020.108271] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 07/03/2020] [Accepted: 08/10/2020] [Indexed: 11/22/2022]
Abstract
For over three-quarters of a century, organophosphorus (OP) insecticides have been ubiquitously used in agricultural, residential, and commercial settings and in public health programs to mitigate insect-borne diseases. Their broad-spectrum insecticidal effectiveness is accounted for by the irreversible inhibition of acetylcholinesterase (AChE), the enzyme that catalyzes acetylcholine (ACh) hydrolysis, in the nervous system of insects. However, because AChE is evolutionarily conserved, OP insecticides are also toxic to mammals, including humans, and acute OP intoxication remains a major public health concern in countries where OP insecticide usage is poorly regulated. Environmental exposures to OP levels that are generally too low to cause marked inhibition of AChE and to trigger acute signs of intoxication, on the other hand, represent an insidious public health issue worldwide. Gestational exposures to OP insecticides are particularly concerning because of the exquisite sensitivity of the developing brain to these insecticides. The present article overviews and discusses: (i) the health effects and therapeutic management of acute OP poisoning during pregnancy, (ii) epidemiological studies examining associations between environmental OP exposures during gestation and health outcomes of offspring, (iii) preclinical evidence that OP insecticides are developmental neurotoxicants, and (iv) potential mechanisms underlying the developmental neurotoxicity of OP insecticides. Understanding how gestational exposures to different levels of OP insecticides affect pregnancy and childhood development is critical to guiding implementation of preventive measures and direct research aimed at identifying effective therapeutic interventions that can limit the negative impact of these exposures on public health.
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Osaghae BE, Arrowsmith S, Wray S. Gestational and Hormonal Effects on Magnesium Sulfate's Ability to Inhibit Mouse Uterine Contractility. Reprod Sci 2020; 27:1570-1579. [PMID: 32430707 DOI: 10.1007/s43032-020-00185-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Magnesium sulfate is used as a tocolytic, but clinical efficacy has been seriously questioned. Our objective was to use controlled ex vivo conditions and known pregnancy stages, to investigate how 2 key factors, hormones and gestation, affect magnesium's tocolytic ability. We hypothesized that these factors could underlie the varying clinical findings around magnesium's efficacy. Myometrial strips were obtained from nonpregnant (n = 10), mid-pregnant (n = 12), and term-pregnant (n = 11) mouse uterus. The strips were mounted in organ baths superfused with oxygenated physiological saline at pH 7.4 and 37 °C. The effect of different concentrations of MgSO4 (2-20 mM) was examined on spontaneous and oxytocin-induced (0.5-1 nM) contractions. Contractile properties (amplitude, frequency, and area under the curve) were measured before and after application of magnesium. Magnesium sulfate had a dose-dependent inhibitory effect on both spontaneous and oxytocin-induced contractions but was less effective in the presence of oxytocin. In spontaneous contractions, magnesium was more potent as gestation progressed (P < .0001). In the presence of oxytocin, however, there were no significant gestational differences in its effects on contraction. The rapid onset and reversal of magnesium's effects suggest an extracellular action on calcium entry. Taken together, we conclude that magnesium's actions are influenced by both gestational state and hormones, such that, at least in mice, it is least effective in early gestation with oxytocin present and most effective at term in the absence of oxytocin. That magnesium is least effective preterm and oxytocin decreases its effectiveness throughout gestation, may explain its disappointing clinical effects as a tocolytic.
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Affiliation(s)
- Blessing E Osaghae
- Department of Molecular and Cellular Physiology, University Department, Harris-Wellbeing Preterm Birth Research Centre, Institute of Translational Medicine, University of Liverpool, First floor Liverpool Women's Hospital, Crown Street, Liverpool, L8 7SS, UK
| | - Sarah Arrowsmith
- Department of Molecular and Cellular Physiology, University Department, Harris-Wellbeing Preterm Birth Research Centre, Institute of Translational Medicine, University of Liverpool, First floor Liverpool Women's Hospital, Crown Street, Liverpool, L8 7SS, UK
| | - Susan Wray
- Department of Molecular and Cellular Physiology, University Department, Harris-Wellbeing Preterm Birth Research Centre, Institute of Translational Medicine, University of Liverpool, First floor Liverpool Women's Hospital, Crown Street, Liverpool, L8 7SS, UK.
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Human Uterine Biopsy: Research Value and Common Pitfalls. Int J Reprod Med 2020; 2020:9275360. [PMID: 32411783 PMCID: PMC7206876 DOI: 10.1155/2020/9275360] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 03/26/2020] [Accepted: 04/10/2020] [Indexed: 12/15/2022] Open
Abstract
The human uterus consists of the inner endometrium, the myometrium, and the outer serosa. Knowledge of the function of the uterus in health and disease is relevant to reproduction, fertility, embryology, gynaecology, endocrinology, and oncology. Research performed on uterine biopsies is essential to further the current understanding of human uterine biology. This brief review explores the value of the uterine biopsy in gynaecological and human fertility research and explores the common problems encountered when analysing data generated from different types of uterine biopsies, with the aim of improving the quality, reproducibility, and clinical translatability of future research.
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Fan Y, Hou W, Xing Y, Zhang L, Zhou C, Gui J, Xu P, Wang A, Fan X, Zeng X, Feng S, Li P. Peptidomics analysis of myometrium tissues in term labor compared with term nonlabor. J Cell Biochem 2019; 121:1890-1900. [PMID: 31709621 DOI: 10.1002/jcb.29424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 10/08/2019] [Indexed: 11/10/2022]
Abstract
Preterm birth (PTB) is a major cause of neonatal mortality, with a poorly understood etiology. The regular contraction of the myometrium was considered as contributing to the etiology of the onset of labor, especially PTB. Thus, studying the mechanism of myometrium contraction is very important for understanding the initiation of labor and also for preventing PTB. Using liquid chromatography-mass spectrometry, we found 322 significantly differential peptides in myometrium tissues between term nonlabor and term labor groups (absolute fold change ≥ 2 and P < .05). We next analyzed length, molecular weights, isoelectric point, and cleavage site of all the different peptides. We, next, analyzed the functions of different peptides through their precursor proteins by Gene Ontology, enrichment and canonical pathway analysis. The results indicated that the extracellular matrix (ECM) played a major role in biological process, the cellular component, and molecular function categories, and revealed that ECM remodeling played a vital role in myometrial contraction. In addition, some known signaling, such as corticotropin-releasing hormone signaling and calcium signaling were proven to be involved in this process. Ingenuity Pathways Analysis upstream regulator analysis suggested that some of the known molecules, which reportedly were very important in labor onset, were included, for example, nuclear factor κB, tubulin, and phosphoinositide 3-kinase. We also identified 23 peptides derived from the precursor protein TITIN, of which 21 peptides sequences from TITIN were located in functional domains. These results suggested that peptides play an important role in labor onset and provide further insight into PTB therapy.
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Affiliation(s)
- Yuru Fan
- Department of Obstetrics, Women's Hospital of Nanjing Medical University (Nanjing Maternity and Child Health Care Hospital), Nanjing, China
| | - Wenwen Hou
- Department of Obstetrics, Women's Hospital of Nanjing Medical University (Nanjing Maternity and Child Health Care Hospital), Nanjing, China
| | - Yuan Xing
- Department of Obstetrics, Women's Hospital of Nanjing Medical University (Nanjing Maternity and Child Health Care Hospital), Nanjing, China
| | - Li Zhang
- Department of Obstetrics, Women's Hospital of Nanjing Medical University (Nanjing Maternity and Child Health Care Hospital), Nanjing, China
| | - Chunxiu Zhou
- Department of Obstetrics, Women's Hospital of Nanjing Medical University (Nanjing Maternity and Child Health Care Hospital), Nanjing, China
| | - Jing Gui
- Department of Obstetrics, Women's Hospital of Nanjing Medical University (Nanjing Maternity and Child Health Care Hospital), Nanjing, China
| | - Pengfei Xu
- Nanjing Maternity and Child Health Care Institute, Women's Hospital of Nanjing Medical University (Nanjing Maternity and Child Health Care Hospital), Nanjing, China
| | - Anming Wang
- Department of Obstetrics, Women's Hospital of Nanjing Medical University (Nanjing Maternity and Child Health Care Hospital), Nanjing, China
| | - Xuemei Fan
- Department of Obstetrics, Women's Hospital of Nanjing Medical University (Nanjing Maternity and Child Health Care Hospital), Nanjing, China
| | - Xin Zeng
- Nanjing Maternity and Child Health Care Institute, Women's Hospital of Nanjing Medical University (Nanjing Maternity and Child Health Care Hospital), Nanjing, China
| | - Shanwu Feng
- Department of Anesthesiology, Women's Hospital of Nanjing Medical University (Nanjing Maternity and Child Health Care Hospital), Nanjing, China
| | - Ping Li
- Department of Gynecology, Women's Hospital of Nanjing Medical University (Nanjing Maternity and Child Health Care Hospital), Nanjing, China
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13
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Bafor EE, Ukpebor F, Omoruyi O, Ochoyama E, Omogiade G, Ekufu J, Edrada-Ebel R. Tocolytic activity assessment of the methanol leaf extract of Justicia flava Vahl (Acanthaceae) on mouse myometrial contractility and preliminary mass spectrometric determination of secondary metabolites. JOURNAL OF ETHNOPHARMACOLOGY 2019; 243:112087. [PMID: 31310827 DOI: 10.1016/j.jep.2019.112087] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 06/26/2019] [Accepted: 07/12/2019] [Indexed: 06/10/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The leaves of Justicia flava are traditionally used in the South of Nigeria to prevent preterm births. AIM OF THE STUDY In this study, the activity of the methanol leaf extract of J. flava (JF) was investigated on uterine contractility in non-pregnant and pregnant isolated mouse tissues. MATERIAL AND METHODS The effects on spontaneous, oxytocin, and KCl-induced contractions were determined. The effects in calcium-free media were also determined. Possible mechanisms of activity were investigated using receptor and channel modulators. Mass spectrometric analysis was additionally performed on the leaf extract to identify secondary metabolites. RESULTS JF was observed to inhibit spontaneous, oxytocin and high KCl-induced uterine contractility. JF also inhibited contractions in Ca2+-free media. JF was found to exert its inhibitory effect via interaction with inositol triphosphate and ryanodine receptors and also through modulation of K+- channels. Lignans and alkaloids were identified with the lignans being the most abundant in JF. CONCLUSION JF has been shown to potently inhibit uterine contractions in non-pregnant and pregnant isolated mouse uterus. The inhibitory activity of JF has been shown to occur via blockade of extracellular and intracellular calcium entry and these effects may be due to the lignans identified in - JF. JF has therefore been shown in this study to be a lead plant in the discovery of new drugs with uterine inhibitory activity.
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Affiliation(s)
- Enitome E Bafor
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, University of Benin, Benin City, Nigeria.
| | - Faith Ukpebor
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, University of Benin, Benin City, Nigeria.
| | - Osemelomen Omoruyi
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, University of Benin, Benin City, Nigeria
| | - Ejiro Ochoyama
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, University of Benin, Benin City, Nigeria
| | - Glory Omogiade
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, University of Benin, Benin City, Nigeria
| | - Jude Ekufu
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, University of Benin, Benin City, Nigeria
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14
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Osaghae BE, Arrowsmith S, Wray S. Gestational and Hormonal Effects on Magnesium Sulfate's Ability to Inhibit Mouse Uterine Contractility. Reprod Sci 2019:1933719119828089. [PMID: 30773125 DOI: 10.1177/1933719119828089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Magnesium sulfate is used as a tocolytic, but clinical efficacy has been seriously questioned. Our objective was to use controlled ex vivo conditions and known pregnancy stages, to investigate how 2 key factors, hormones and gestation, affect magnesium's tocolytic ability. We hypothesized that these factors could underlie the varying clinical findings around magnesium's efficacy. Myometrial strips were obtained from nonpregnant (n = 10), mid-pregnant (n = 12), and term-pregnant (n = 11) mouse uterus. The strips were mounted in organ baths superfused with oxygenated physiological saline at pH 7.4 and 37°C. The effect of different concentrations of MgSO4 (2-20 mM) was examined on spontaneous and oxytocin-induced (0.5-1 nM) contractions. Contractile properties (amplitude, frequency, and area under the curve) were measured before and after application of magnesium. Magnesium sulfate had a dose-dependent inhibitory effect on both spontaneous and oxytocin-induced contractions but was less effective in the presence of oxytocin. In spontaneous contractions, magnesium was more potent as gestation progressed ( P < .0001). In the presence of oxytocin, however, there were no significant gestational differences in its effects on contraction. The rapid onset and reversal of magnesium's effects suggest an extracellular action on calcium entry. Taken together, we conclude that magnesium's actions are influenced by both gestational state and hormones, such that, at least in mice, it is least effective in early gestation with oxytocin present and most effective at term in the absence of oxytocin. That magnesium is least effective preterm and oxytocin decreases its effectiveness throughout gestation, may explain its disappointing clinical effects as a tocolytic.
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Affiliation(s)
- Blessing E Osaghae
- 1 Department of Cellular and Molecular Physiology, University Department, Harris-Wellbeing Preterm Birth Research Centre, The Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Sarah Arrowsmith
- 1 Department of Cellular and Molecular Physiology, University Department, Harris-Wellbeing Preterm Birth Research Centre, The Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Susan Wray
- 1 Department of Cellular and Molecular Physiology, University Department, Harris-Wellbeing Preterm Birth Research Centre, The Institute of Translational Medicine, University of Liverpool, Liverpool, UK
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15
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Koli S, Prakash A, Choudhury S, Mandil R, Garg SK. Calcium Channels, Rho-Kinase, Protein Kinase-C, and Phospholipase-C Pathways Mediate Mercury Chloride-Induced Myometrial Contractions in Rats. Biol Trace Elem Res 2019; 187:418-424. [PMID: 29785630 DOI: 10.1007/s12011-018-1379-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 05/07/2018] [Indexed: 01/30/2023]
Abstract
Adverse effects of mercury on female reproduction are reported; however, its effect on myogenic activity of uterus and mechanism thereof is obscure. Present study was undertaken to unravel the mechanistic pathways of mercuric chloride (HgCl2)-induced myometrial contraction in rats. Isometric tension in myometrial strips of rats following in vitro exposure to HgCl2 was recorded using data acquisition system-based physiograph. HgCl2 produced concentration-dependent (10 nM-100 μM) uterotonic effect which was significantly (p < 0.05) reduced in Ca2+-free solution and inhibited in the presence of nifedipine (1 μM), a L-type Ca2+ channel blocker, thus suggesting the importance of extracellular Ca2+ and its entry through L-type calcium channels in HgCl2-induced myometrial contractions in rats. Cumulative concentration-response curve of HgCl2 was significantly (p < 0.05) shifted towards right in the presence of Y-27632 (10 μM), a Rho-kinase inhibitor, suggesting the involvement of Ca2+-sensitization pathway in mediating HgCl2-induced myometrial contraction. HgCl2-induced myometrial contraction was also significantly (p < 0.05) inhibited in the presence of methoctramine or para-fluoro-hexahydro-siladifenidol, a selective M2 and M3 receptor antagonists, respectively, which evidently suggest that mercury also interacts with M2 and M3 muscarinic receptors to produce myometrial contractions. U-73122 and GF-109203X, the respective inhibitors of PLC and PKC-dependent pathways, downstream to the receptor activation, also significantly (p < 0.05) attenuated the uterotonic effect of HgCl2 on rat uterus. Taken together, present study evidently reveals that HgCl2 interacts with muscarinic receptors and activates calcium signaling cascades involving calcium channels, Rho-kinase, protein kinase-C, and phospholipase-C pathways to exert uterotonic effect in rats. Graphical Abstract Graphical abstract depicting the mechanism of mercury-induced myometrial contraction in rats. M receptor: Muscarinic receptor; PIP2: phospho-inositol bisphosphate; PLC: phospholipase-C; DAG: diacyl glycerol; IP3: inositol triphosphate; IP3R: inositol triphosphate receptor; PKC; protein kinase-C; MLCP: myosin light chain phosphatise; MYPT: myosin phosphatase; SR: sarco-endoplasmic reticulum.
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Affiliation(s)
- Swati Koli
- Experimental Pharmacology Laboratory, Department of Veterinary Pharmacology and Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan (DUVASU), Mathura, 281001 (U.P.), India
| | - Atul Prakash
- Experimental Pharmacology Laboratory, Department of Veterinary Pharmacology and Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan (DUVASU), Mathura, 281001 (U.P.), India
| | - Soumen Choudhury
- Experimental Pharmacology Laboratory, Department of Veterinary Pharmacology and Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan (DUVASU), Mathura, 281001 (U.P.), India
| | - Rajesh Mandil
- Experimental Pharmacology Laboratory, Department of Veterinary Pharmacology and Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan (DUVASU), Mathura, 281001 (U.P.), India
| | - Satish K Garg
- Experimental Pharmacology Laboratory, Department of Veterinary Pharmacology and Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan (DUVASU), Mathura, 281001 (U.P.), India.
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16
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Muñoz-Pérez VM, Ortiz MI, Ponce-Monter HA, Monter-Pérez V, Barragán-Ramírez G. Anti-inflammatory and utero-relaxant effect of α-bisabolol on the pregnant human uterus. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2018; 22:391-398. [PMID: 29962853 PMCID: PMC6019870 DOI: 10.4196/kjpp.2018.22.4.391] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 01/25/2018] [Accepted: 02/09/2018] [Indexed: 12/16/2022]
Abstract
The aim of this study was to evaluate the in vitro anti-inflammatory and utero-relaxant effect of α-bisabolol on the pregnant human myometrium. Samples from the pregnant human myometrium were used in functional tests to evaluate the inhibitory effect of α-bisabolol (560, 860, 1,200 and 1,860 µM) on spontaneous myometrial contractions. The intracellular cyclic adenosine monophosphate (cAMP) levels generated in response to α-bisabolol in human myometrial homogenates were measured by ELISA. The anti-inflammatory effect of α-bisabolol was determined through the measurement of two pro-inflammatory cytokines, tumor necrosis factor-α (TNFα) and interleukin (IL)-1β, and the anti-inflammatory cytokine IL-10, in pregnant human myometrial explants stimulated with lipopolysaccharide (LPS). Forskolin was used as a positive control to evaluate the cAMP and cytokine levels. α-Bisabolol was found to induce a significant inhibition of spontaneous myometrial contractions at the highest concentration level (p<0.05). α-Bisabolol caused a concentration-dependent decrease in myometrial cAMP levels (p<0.05) and a concentration-dependent decrease in LPS-induced TNFα and IL-1β production, while IL-10 production did not increase significantly (p>0.05). The anti-inflammatory and utero-relaxant effects induced by α-bisabolol were not associated with an increase in cAMP levels in pregnant human myometrial samples. These properties place α-bisabolol as a potentially safe and effective adjuvant agent in cases of preterm birth, an area of pharmacological treatment that requires urgent improvement.
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Affiliation(s)
- Victor Manuel Muñoz-Pérez
- Área Académica de Medicina del Instituto de Ciencias de la Salud. Universidad Autónoma del Estado de Hidalgo, Pachuca, Hidalgo, México
| | - Mario I Ortiz
- Área Académica de Medicina del Instituto de Ciencias de la Salud. Universidad Autónoma del Estado de Hidalgo, Pachuca, Hidalgo, México
| | - Héctor A Ponce-Monter
- Área Académica de Medicina del Instituto de Ciencias de la Salud. Universidad Autónoma del Estado de Hidalgo, Pachuca, Hidalgo, México
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17
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Arrowsmith S, Keov P, Muttenthaler M, Gruber CW. Contractility Measurements of Human Uterine Smooth Muscle to Aid Drug Development. J Vis Exp 2018. [PMID: 29443077 PMCID: PMC5841565 DOI: 10.3791/56639] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Discovery and characterization of novel pharmaceutical compounds or biochemical probes rely on robust and physiologically relevant assay systems. We describe methods to measure ex vivo myometrium contractility. This assay can be used to investigate factors and molecules involved in the modulation of myometrial contraction and to determine their excitatory or inhibitory actions, and hence their therapeutic potential in vivo. Biopsies are obtained from women undergoing cesarean section delivery with informed consent. Fine strips of myometrium are dissected, clipped and attached to a force transducer within 1 mL organ baths superfused with physiological saline solution at 37 °C. Strips develop spontaneous contractions within 2-3 h under set tension and remain stable for many hours (>6 h). Strips can also be stimulated to contract such as by the endogenous hormones, oxytocin and vasopressin, which cause concentration-dependent modulation of contraction frequency, force and duration, to more closely resemble contractions in labor. Hence, the effect of known and novel drug leads can be tested on spontaneous and agonist-induced contractions. This protocol specifically details how this assay can be used to determine the potency of known and novel agents by measuring their effects on various parameters of human myometrial contraction. We use the oxytocin- and V1a receptor antagonists, atosiban and SR49059 as examples of known compounds which inhibit oxytocin- and vasopressin-induced contractions, and demonstrate how this method can be used to complement and validate pharmacological data obtained from cell-based assays to aid drug development. The effects of novel agonists in comparison to oxytocin and vasopressin can also be characterized. Whilst we use the example of the oxytocin/ vasopressin system, this method can also be used to study other receptors and ion channels that play a role in uterine contraction and relaxation to advance the understanding of human uterine physiology and pathophysiology.
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Affiliation(s)
- Sarah Arrowsmith
- Harris-Wellbeing Preterm Birth Research Centre, Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool;
| | - Peter Keov
- School of Biomedical Sciences, The University of Queensland
| | - Markus Muttenthaler
- Faculty of Chemistry, Institute of Biological Chemistry, University of Vienna; Institute for Molecular Bioscience, University of Queensland
| | - Christian W Gruber
- School of Biomedical Sciences, The University of Queensland; Center for Physiology and Pharmacology, Medical University of Vienna;
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18
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Muttenthaler M, Andersson Å, Vetter I, Menon R, Busnelli M, Ragnarsson L, Bergmayr C, Arrowsmith S, Deuis JR, Chiu HS, Palpant NJ, O'Brien M, Smith TJ, Wray S, Neumann ID, Gruber CW, Lewis RJ, Alewood PF. Subtle modifications to oxytocin produce ligands that retain potency and improved selectivity across species. Sci Signal 2017; 10:10/508/eaan3398. [PMID: 29208680 DOI: 10.1126/scisignal.aan3398] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Oxytocin and vasopressin mediate various physiological functions that are important for osmoregulation, reproduction, cardiovascular function, social behavior, memory, and learning through four G protein-coupled receptors that are also implicated in high-profile disorders. Targeting these receptors is challenging because of the difficulty in obtaining ligands that retain selectivity across rodents and humans for translational studies. We identified a selective and more stable oxytocin receptor (OTR) agonist by subtly modifying the pharmacophore framework of human oxytocin and vasopressin. [Se-Se]-oxytocin-OH displayed similar potency to oxytocin but improved selectivity for OTR, an effect that was retained in mice. Centrally infused [Se-Se]-oxytocin-OH potently reversed social fear in mice, confirming that this action was mediated by OTR and not by V1a or V1b vasopressin receptors. In addition, [Se-Se]-oxytocin-OH produced a more regular contraction pattern than did oxytocin in a preclinical labor induction and augmentation model using myometrial strips from cesarean sections. [Se-Se]-oxytocin-OH had no activity in human cardiomyocytes, indicating a potentially improved safety profile and therapeutic window compared to those of clinically used oxytocin. In conclusion, [Se-Se]-oxytocin-OH is a novel probe for validating OTR as a therapeutic target in various biological systems and is a promising new lead for therapeutic development. Our medicinal chemistry approach may also be applicable to other peptidergic signaling systems with similar selectivity issues.
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Affiliation(s)
- Markus Muttenthaler
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia. .,Faculty of Chemistry, Institute of Biological Chemistry, University of Vienna, 1090 Vienna, Austria
| | - Åsa Andersson
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia.,School of Pharmacy, The University of Queensland, Brisbane, Queensland 4104, Australia
| | - Rohit Menon
- Department of Behavioral and Molecular Neurobiology, Regensburg Center of Neuroscience, University of Regensburg, 93053 Regensburg, Germany
| | - Marta Busnelli
- CNR-Institute of Neuroscience, 20129 Milan, Italy.,Department of Biotechnology and Translational Medicine, University of Milan, 20129 Milan, Italy
| | - Lotten Ragnarsson
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Christian Bergmayr
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Sarah Arrowsmith
- Department of Cellular and Molecular Physiology, Harris-Wellbeing Preterm Birth Centre, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, UK
| | - Jennifer R Deuis
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Han Sheng Chiu
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Nathan J Palpant
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Margaret O'Brien
- National Centre for Biomedical Engineering Science, National University of Ireland, Galway H91 CF50, Ireland
| | - Terry J Smith
- National Centre for Biomedical Engineering Science, National University of Ireland, Galway H91 CF50, Ireland
| | - Susan Wray
- Department of Cellular and Molecular Physiology, Harris-Wellbeing Preterm Birth Centre, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, UK
| | - Inga D Neumann
- Department of Behavioral and Molecular Neurobiology, Regensburg Center of Neuroscience, University of Regensburg, 93053 Regensburg, Germany
| | - Christian W Gruber
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria.,School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Richard J Lewis
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Paul F Alewood
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia.
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19
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Sharma A, Nakade UP, Jaitley P, Sharma V, Choudhury S, Garg SK. WITHDRAWN: Differential involvement of L- and T-type Ca 2+ channels, store-operated calcium channel (TRPC) and Rho-kinase signaling pathway(s) in PGF 2α-induced contractions in myometrium of non-pregnant and pregnant buffaloes (Bubalus bubalis). Prostaglandins Other Lipid Mediat 2017:S1098-8823(17)30021-7. [PMID: 28916261 DOI: 10.1016/j.prostaglandins.2017.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 09/05/2017] [Accepted: 09/06/2017] [Indexed: 11/30/2022]
Abstract
This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.
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Affiliation(s)
- Abhishek Sharma
- Experimental Pharmacology Laboratory, Department of Pharmacology & Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya, Evam Go-Anusandhan Sansthan (DUVASU), Mathura 281001, India
| | - Udayraj P Nakade
- Experimental Pharmacology Laboratory, Department of Pharmacology & Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya, Evam Go-Anusandhan Sansthan (DUVASU), Mathura 281001, India
| | - Pooja Jaitley
- Experimental Pharmacology Laboratory, Department of Pharmacology & Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya, Evam Go-Anusandhan Sansthan (DUVASU), Mathura 281001, India
| | - Vipin Sharma
- Experimental Pharmacology Laboratory, Department of Pharmacology & Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya, Evam Go-Anusandhan Sansthan (DUVASU), Mathura 281001, India
| | - Soumen Choudhury
- Experimental Pharmacology Laboratory, Department of Pharmacology & Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya, Evam Go-Anusandhan Sansthan (DUVASU), Mathura 281001, India
| | - Satish Kumar Garg
- Experimental Pharmacology Laboratory, Department of Pharmacology & Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya, Evam Go-Anusandhan Sansthan (DUVASU), Mathura 281001, India.
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20
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Functional involvement of protein kinase C, Rho-kinase and TRPC3 decreases while PLC increases with advancement of pregnancy in mediating oxytocin-induced myometrial contractions in water buffaloes ( Bubalus bubalis ). Theriogenology 2017; 92:176-189. [DOI: 10.1016/j.theriogenology.2016.12.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 12/06/2016] [Accepted: 12/06/2016] [Indexed: 11/20/2022]
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21
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Sharma A, Nakade UP, Choudhury S, Yadav RS, Garg SK. Extra and intracellular calcium signaling pathway(s) differentially regulate histamine-induced myometrial contractions during early and mid-pregnancy stages in buffaloes (Bubalus bubalis). Anim Reprod Sci 2017; 179:10-19. [PMID: 28228338 DOI: 10.1016/j.anireprosci.2017.01.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 01/18/2017] [Accepted: 01/25/2017] [Indexed: 10/20/2022]
Abstract
This study examines the differential role of calcium signaling pathway(s) in histamine-induced uterotonic action during early and mid-pregnancy stages in buffaloes. Compared to mid pregnancy, tonic contraction, amplitude and mean-integral tension were significantly increased by histamine to produce myometrial contraction during early pregnancy with small effects on phasic contraction and frequency. Although uterotonic action of histamine during both stages of pregnancy is sensitive to nifedipine (a L-type Ca2+ channels blocker) and NNC55-0396 (T-type Ca2+ channels blocker), the role of extracellular calcium seems to be more significant during mid-pregnancy as in this stage histamine produced only 9.38±0.96% contraction in Ca2+ free-RLS compared to 21.60±1.45% in uteri of early pregnancy stage. Intracellular calcium plays major role in histamine-induced myometrial contraction during early pregnancy as compared to mid pregnancy, as in the presence of cyclopiazonic acid (CPA) Ca2+-free RLS, histamine produced significantly higher contraction in myometrial strips of early-pregancy in comparison to mid-pregnancy (10.59±1.58% and 3.13±0.46%, respectively). In the presence of U-73122, the DRC of histamine was significantly shifted towards right with decrease in maximal effect (Emax) only in early pregnancy suggesting the predominant role of phospholipase-C (PL-C) in this stage of pregnancy.
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Affiliation(s)
- Abhishek Sharma
- Experimental Pharmacology Laboratory, Department of Pharmacology and Toxicology, College of Veterinary Science and Animal Husbandry, UP Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan, Mathura, U.P., 281 001, India
| | - Udayraj P Nakade
- Experimental Pharmacology Laboratory, Department of Pharmacology and Toxicology, College of Veterinary Science and Animal Husbandry, UP Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan, Mathura, U.P., 281 001, India
| | - Soumen Choudhury
- Experimental Pharmacology Laboratory, Department of Pharmacology and Toxicology, College of Veterinary Science and Animal Husbandry, UP Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan, Mathura, U.P., 281 001, India
| | - Rajkumar Singh Yadav
- Experimental Pharmacology Laboratory, Department of Pharmacology and Toxicology, College of Veterinary Science and Animal Husbandry, UP Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan, Mathura, U.P., 281 001, India
| | - Satish Kumar Garg
- Experimental Pharmacology Laboratory, Department of Pharmacology and Toxicology, College of Veterinary Science and Animal Husbandry, UP Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan, Mathura, U.P., 281 001, India.
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22
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Affiliation(s)
- B. F. Mitchell
- Perinatal Research Centre, Department of Obstetrics and Gynecology, University of Alberta, Edmonton, Alberta, Canada
| | - Birgit Schmid
- Perinatal Research Centre, Department of Obstetrics and Gynecology, University of Alberta, Edmonton, Alberta, Canada
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23
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Affiliation(s)
- Barbara M. Sanborn
- Department of Biochemistry and Molecular Biology, University of Texas Houston Medical School, PO Box 20708, Houston, TX 77225
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Matthew A, Kupittayanant S, Burdyga T, Wray S. Characterization of Contractile Activity and Intracellular Ca2+ Signalling in Mouse Myometrium. ACTA ACUST UNITED AC 2016; 11:207-12. [PMID: 15120693 DOI: 10.1016/j.jsgi.2003.10.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
OBJECTIVE To characterize the contractile responses of mouse myometrium, the associated calcium (Ca2+) changes and the role of the sarcoplasmic reticulum (SR), and to better understand excitation contraction coupling in this tissue. METHODS Strips of longitudinal myometrium were used, and Ca2+ was measured after loading with Indo-1. RESULTS Intracellular Ca2+ transients, produced by Ca2+ entry, preceded phasic spontaneous contractions. Depolarization with high potassium concentration significantly increased the amplitude of the contractions and transformed the pattern of activity from phasic to tonic, with accompanying changes in intracellular Ca2+ concentration ([Ca2+]i). Oxytocin significantly stimulated contractile activity and [Ca2+]i above the level occurring spontaneously. Thus all forms of contractile activity were closely correlated with Ca2+. When the SR was emptied using a blocker of the SR calcium-adenosinetriphosphatase, cyclopiazonic acid, spontaneous Ca2+ and force transients increased greatly in frequency and amplitude. Ryanodine, a blocker of Ca(2+)-induced Ca2+ release (CICR), did not impair activity. In the absence of external Ca2+, oxytocin was able to release Ca2+ from the SR through IP3 but produced only a small increase in force, demonstrating a requirement for Ca2+ entry as part of the mechanism of agonist action. CONCLUSION Mouse myometrium, (1) produces contractile activity reflecting changes in [Ca2+]i irrespective of the stimulus, (2) has a significant SR Ca2+ content releasable by agonists but not CICR, (3) has an SR acting to inhibit spontaneous activity, and (4) behaves qualitatively similarly to human and rat myometrium in major aspects of excitation contraction coupling and is therefore a useful model tissue.
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Affiliation(s)
- A Matthew
- Department of Physiology, The University of Liverpool, United Kingdom
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Talati C, Ramachandran N, Carvalho JCA, Kingdom J, Balki M. The Effect of Extracellular Calcium on Oxytocin-Induced Contractility in Naive and Oxytocin-Pretreated Human Myometrium In Vitro. Anesth Analg 2016; 122:1498-507. [DOI: 10.1213/ane.0000000000001264] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Attah AF, Hellinger R, Sonibare MA, Moody JO, Arrowsmith S, Wray S, Gruber CW. Ethnobotanical survey of Rinorea dentata (Violaceae) used in South-Western Nigerian ethnomedicine and detection of cyclotides. JOURNAL OF ETHNOPHARMACOLOGY 2016; 179:83-91. [PMID: 26721222 PMCID: PMC5858781 DOI: 10.1016/j.jep.2015.12.038] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 12/18/2015] [Accepted: 12/21/2015] [Indexed: 05/23/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE People living in the tropical rain forest of South-Western Nigeria use Rinorea dentata (P. Beauv.) Kuntze (Violaceae) in ethno-veterinary medicine to facilitate parturition. There are no evidence-based pharmacological investigations for the uterotonic activity of this plant. AIMS OF STUDY (i) Collection of data about the ethnopharmacological uses of R. dentata and evaluation of its uses and applications in health care; (ii) determining potential uterotonic effects in vitro, and (iii) chemical characterization of R. dentata, which is a member of the Violaceae family known to express circular cystine-knot peptides, called cyclotides. MATERIALS AND METHODS The ethnopharmacological use of R. dentata in settlement camps within the area J4 of Omo forest has been investigated by semi-structured questionnaires and open interviews. Use index analysis has been performed by seven quantitative statistical models. Respondents' claim on the beneficial ethno-veterinary application of the plant to aid parturition has been investigated in vitro by myometrial contractility organ bath assays. The bioactive plant extract was screened by chemical derivatization and mass spectrometry-based peptidomics using reversed-phase HPLC fractionation and MALDI-TOF/TOF analysis. RESULTS Based on the survey analysis, medicinal preparations of R. dentata have been used for anti-microbial and anti-malaria purpose in humans, and for aiding parturition in farm animals. The latter application was mentioned by one out of six respondents who claimed to use this plant for any medicinal purpose. The plant extract exhibited a weak uterotonic effect using organ bath studies. The plant contains cyclotides and the peptide riden A has been identified by de novo amino acid sequencing using mass spectrometry. CONCLUSION Few dwellers around the settlement camps of the tropical forest of Omo (Nigeria) use R. dentata for various health problems in traditional veterinary and human medicine. The weak uterotonic effect of the cyclotide-rich extract is in agreement with the low use value index obtained for this plant. Cyclotides have been reported in the genus Rinorea confirming the ubiquitous expression of these stable bioactive plant peptides within the family of Violaceae.
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Affiliation(s)
- Alfred F Attah
- Department of Pharmacognosy, Faculty of Pharmacy, University of Ibadan, Ibadan, Nigeria; Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstr. 17, A-1090 Vienna, Austria
| | - Roland Hellinger
- Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstr. 17, A-1090 Vienna, Austria
| | - Mubo A Sonibare
- Department of Pharmacognosy, Faculty of Pharmacy, University of Ibadan, Ibadan, Nigeria
| | - Jones O Moody
- Department of Pharmacognosy, Faculty of Pharmacy, University of Ibadan, Ibadan, Nigeria
| | - Sarah Arrowsmith
- Department of Cellular and Molecular Physiology, Harris-Wellbeing Preterm Birth Centre, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Susan Wray
- Department of Cellular and Molecular Physiology, Harris-Wellbeing Preterm Birth Centre, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Christian W Gruber
- Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstr. 17, A-1090 Vienna, Austria; School of Biomedical Sciences, The University of Queensland, Brisbane, Qld 4072, Australia.
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Wray S. Insights from physiology into myometrial function and dysfunction. Exp Physiol 2015; 100:1468-76. [PMID: 26289390 DOI: 10.1113/ep085131] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 08/17/2015] [Indexed: 12/12/2022]
Abstract
NEW FINDINGS What is the topic of this review? I focus on clinical aspects of uterine physiology, specifically, myometrial contractility. I bring together and contrast findings using physiological approaches and those using newer techniques, 'omics'. What advances does it highlight? Physiological studies have recently shed light on the myometrium in twin pregnancies, but there have been no 'omic' approaches. In contrast, studies of preterm delivery using newer approaches are generating new research avenues, whereas traditional approaches have not flourished. Finally, I describe significant advances in understanding of 'slow-to-progress' labours, achieved using physiological and clinical approaches. Advances in molecular, genetic and 'omic' technologies are fuelling the thirst for better understanding of the uterus and application of this information to problems in pregnancy and labour. Progress has, however, been limited while we still have an incomplete understanding of some of the basic physiology of uterine smooth muscle (myometrium). In this review and opinion piece, I explore some of the fascinating findings from selected recent studies and see how these may provide new avenues for physiological and clinical research. It is also the case, however, that there is still limited mechanistic understanding about physiological and pathophysiological processes in the myometrium. This lack of understanding limits the usefulness of some findings from genomic and allied studies. By focusing on some key recent findings and relating these to two important clinical problems in childbirth that involve myometrial activity, namely preterm delivery and difficult labours, the interplay between our physiological knowledge and the information provided by newer technologies is explored. My opinion is that physiology has provided much more new mechanistic insight into difficult births and that the newer technologies may lead to breakthroughs in preterm birth research, but that this has not yet happened.
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Affiliation(s)
- Susan Wray
- Harris/Wellbeing Centre for Preterm Birth Research, Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
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Mumtaz S, AlSaif S, Wray S, Noble K. Inhibitory effect of visfatin and leptin on human and rat myometrial contractility. Life Sci 2015; 125:57-62. [DOI: 10.1016/j.lfs.2015.01.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 01/20/2015] [Accepted: 01/23/2015] [Indexed: 12/01/2022]
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Singh V, Ram M, Kandasamy K, Thangamalai R, Choudhary S, Dash JR, Kumar D, Parida S, Singh TU, Mishra SK. Molecular and functional characterization of TRPV4 channels in pregnant and nonpregnant mouse uterus. Life Sci 2015; 122:51-8. [DOI: 10.1016/j.lfs.2014.12.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 11/12/2014] [Accepted: 12/05/2014] [Indexed: 02/06/2023]
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Xu C, You X, Liu W, Sun Q, Ding X, Huang Y, Ni X. Prostaglandin F2α regulates the expression of uterine activation proteins via multiple signalling pathways. Reproduction 2015; 149:139-46. [DOI: 10.1530/rep-14-0479] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Prostaglandin F2α (PGF2A) has multiple roles in the birth process in addition to its vital contractile role. Our previous study has demonstrated that PGF2A can modulate uterine activation proteins (UAPs) in cultured pregnant human myometrial smooth muscle cells (HMSMCs). The objective of this study was to define the signalling pathways responsible for PGF2A modulation of UAPs in myometrium. It was found that PGF2A stimulated the expression of (GJA1) connexin 43 (CX43), prostaglandin endoperoxide synthase 2 (PTGS2) and oxytocin receptor (OTR) in cultured HMSMCs. The inhibitors of phospholipase C (PLC) and protein kinase C (PKC) blocked PGF2A-stimulated expression of CX43. The inhibitors of ERK, P38 and NFκB also blocked the effect of PGF2A on CX43 expression, whereas PI3K and calcineurin/nuclear factor of activated T-cells (NFAT) pathway inhibitors did not reverse the effect of PGF2A on CX43. For PTGS2 and OTR, PLC, PI3K, P38 and calcineurin/NFAT signalling pathways were involved in PGF2A action, whereas PKC and NFκB signalling were not involved. In addition, PGF2A activated NFAT, PI3K, NFκB, ERK and P38 signalling pathways. Our data suggest that PGF2A stimulates CX43, PTGS2 and OTR through divergent signalling pathways.
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Store-operated Ca²⁺ entry and depolarization explain the anomalous behaviour of myometrial SR: effects of SERCA inhibition on electrical activity, Ca²⁺ and force. Cell Calcium 2014; 56:188-94. [PMID: 25084623 PMCID: PMC4169181 DOI: 10.1016/j.ceca.2014.07.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 07/03/2014] [Accepted: 07/09/2014] [Indexed: 11/23/2022]
Abstract
SERCA pump inhibition by CPA caused membrane depolarization, activation of action potentials, Ca2+ spikes and force. Depletion of Ca2+ store by agonists leads to membrane depolarization and activation of electrical and mechanical activity. Ca2+ release/Ca2+ entry coupling is playing a key role in control of spontaneous electrical and mechanical activity in rat pregnant myometrium.
In the myometrium SR Ca2+ depletion promotes an increase in force but unlike several other smooth muscles, there is no Ca2+ sparks-STOCs coupling mechanism to explain this. Given the importance of the control of contractility for successful parturition, we have examined, in pregnant rat myometrium, the effects of SR Ca2+-ATPase (SERCA) inhibition on the temporal relationship between action potentials, Ca2+ transients and force. Simultaneous recording of electrical activity, calcium and force showed that SERCA inhibition, by cyclopiazonic acid (CPA 20 μM), caused time-dependent changes in excitability, most noticeably depolarization and elevations of baseline [Ca2+]i and force. At the onset of these changes there was a prolongation of the bursts of action potentials and a corresponding series of Ca2+ spikes, which increased the amplitude and duration of contractions. As the rise of baseline Ca2+ and depolarization continued a point was reached when electrical and Ca2+ spikes and phasic contractions ceased, and a maintained, tonic force and Ca2+ was produced. Lanthanum, a non-selective blocker of store-operated Ca2+ entry, but not the L-type Ca2+ channel blocker nifedipine (1–10 μM), could abolish the maintained force and calcium. Application of the agonist, carbachol, produced similar effects to CPA, i.e. depolarization, elevation of force and calcium. A brief, high concentration of carbachol, to cause SR Ca2+ depletion without eliciting receptor-operated channel opening, also produced these results. The data obtained suggest that in pregnant rats SR Ca2+ release is coupled to marked Ca2+ entry, via store operated Ca2+ channels, leading to depolarization and enhanced electrical and mechanical activity.
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Arrowsmith S, Wray S. Oxytocin: its mechanism of action and receptor signalling in the myometrium. J Neuroendocrinol 2014; 26:356-69. [PMID: 24888645 DOI: 10.1111/jne.12154] [Citation(s) in RCA: 161] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 03/14/2014] [Accepted: 03/28/2014] [Indexed: 12/17/2022]
Abstract
Oxytocin is a nonapeptide hormone that has a central role in the regulation of parturition and lactation. In this review, we address oxytocin receptor (OTR) signalling and its role in the myometrium during pregnancy and in labour. The OTR belongs to the rhodopsin-type (Class 1) of the G-protein coupled receptor superfamily and is regulated by changes in receptor expression, receptor desensitisation and local changes in oxytocin concentration. Receptor activation triggers a number of signalling events to stimulate contraction, primarily by elevating intracellular calcium (Ca(2+) ). This includes inositol-tris-phosphate-mediated store calcium release, store-operated Ca(2+) entry and voltage-operated Ca(2+) entry. We discuss each mechanism in turn and also discuss Ca(2+) -independent mechanisms such as Ca(2+) sensitisation. Because oxytocin induces contraction in the myometrium, both the activation and the inhibition of its receptor have long been targets in the management of dysfunctional and preterm labours, respectively. We discuss current and novel OTR agonists and antagonists and their use and potential benefit in obstetric practice. In this regard, we highlight three clinical scenarios: dysfunctional labour, postpartum haemorrhage and preterm birth.
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Affiliation(s)
- S Arrowsmith
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
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Sharma A, Choudhury S, Nakade UP, Yadav RS, Garg SK. Calcium influx and release mechanism(s) in histamine-induced myometrial contraction in buffaloes. Anim Reprod Sci 2014; 146:157-64. [PMID: 24631173 DOI: 10.1016/j.anireprosci.2014.02.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 02/02/2014] [Accepted: 02/15/2014] [Indexed: 01/10/2023]
Abstract
The present study was undertaken to characterize the presence of histamine H1R using molecular biology tools and unravel the influx and release mechanism(s) involved in calcium signalling cascades in histamine-induced myometrial contraction in buffaloes. The presence of H1R mRNA transcript and immunoreactive membrane protein in buffalo myometrium was confirmed by RT-PCR and Western blot analysis. Further, histamine produced concentration-dependent (1nM-10μM) contraction in buffalo myometrium with a potency of 7.13±0.11. When myometrial strips were pre-incubated either with Ca(2+) free solution or with nifedipine, a L-type Ca(2+) channel blocker, dose response curve (DRC) of histamine was significantly (P<0.05) shifted towards right with decline in maximal contraction (Emax). Reduction in Emax of histamine in the presence of nifedipine (55.75±3.10%) was significantly (P<0.001) greater than that in the presence of ruthenium red (93.61±3.43%), a blocker of IP3-gated and RyR-sensitive Ca(2+) channels. Moreover, histamine produced only 26.87±1.99% of the maximum contraction in the presence of both nifedipine and CPA (blocker of sarco-endoplasmic reticulum Ca(2+)-ATPase). Interestingly, following concurrent exposure to U-73122 (a PL-C inhibitor) and nifedipine, the DRC of histamine was significantly (P<0.05) shifted towards left with increase in maximal contraction (126.30±3.36%). Our findings in buffalo uterus thus suggest that influx of extracellular calcium plays a major role in histamine-induced myometrial contraction, while release of intracellular calcium through calcium-release channels of sarcoplasmic reticulum has a minor role. A possible involvement of non-selective cation channels in histamine-induced myometrial contraction cannot be ruled out, and therefore requires further investigations.
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Affiliation(s)
- Abhishek Sharma
- Department of Pharmacology & Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan, Mathura 281001, India
| | - Soumen Choudhury
- Department of Pharmacology & Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan, Mathura 281001, India
| | - Udayraj P Nakade
- Department of Pharmacology & Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan, Mathura 281001, India
| | - Rajkumar Singh Yadav
- Department of Pharmacology & Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan, Mathura 281001, India
| | - Satish Kumar Garg
- Department of Pharmacology & Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan, Mathura 281001, India.
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Kupittayanant S, Munglue P, Lijuan W, Promprom W, Budhaklala N, Wray S. Finding new agents in medicinal plants to act on the myometrium. Exp Physiol 2014; 99:530-7. [DOI: 10.1113/expphysiol.2013.072884] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Sajeera Kupittayanant
- Institute of Science; Suranaree University of Technology; Muang District Nakhon Ratchasima Thailand
| | - Phukphon Munglue
- Faculty of Science; Ubon Ratchathani Rajabhat University; Muang District Ubon Ratchathani Thailand
| | - Wanwisa Lijuan
- Faculty of Science and Technology; Thepsatri Rajabhat University; Muang Lop Buri Lobburi Thailand
| | - Wilawan Promprom
- Faculty of Science; Mahasarakham University; Kantrawichai Mahasarakham Thailand
| | - Nopparat Budhaklala
- Faculty of Science; Rajamangala University of Technology Thanyaburi; Thanyaburi Pathum Thani Thailand
| | - Susan Wray
- Department of Cellular and Molecular Physiology; Institute of Translational Medicine; University of Liverpool; Liverpool UK
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Pehlivanoğlu B, Bayrak S, Doğan M. A close look at the contraction and relaxation of the myometrium; the role of calcium. J Turk Ger Gynecol Assoc 2013; 14:230-4. [PMID: 24592112 DOI: 10.5152/jtgga.2013.67763] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 08/12/2013] [Indexed: 11/22/2022] Open
Abstract
The function and regulation of the myometrium, especially during pregnancy, labour and birth are important in reproductive physiology. It is crucial to understand the mechanisms that generate and modulate uterine contractility in order to be able to prevent and/or treat the problems related with the myometrium. A limited understanding of the cellular and molecular events underlying these phenomena complicates the situation. Various agonists, hormones, transmitters and/or chemicals are related to the regulation of the functions of the myometrium. Although notable advances regarding the key steps in receptor signalling explaining the actions of these factors have been achieved, a good deal of information is still necessary to understand this vital process. A better comprehension of myometrium physiology and the translation of research findings to clinical settings will help progress in women's health. In this review, we attempt to present a critical overview of myometrial functions and focus specifically on the role of calcium.
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Affiliation(s)
- Bilge Pehlivanoğlu
- Department of Physiology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Sibel Bayrak
- Department of Physiology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Murat Doğan
- Department of Physiology, Hacettepe University Faculty of Medicine, Ankara, Turkey
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Oxytocic plant cyclotides as templates for peptide G protein-coupled receptor ligand design. Proc Natl Acad Sci U S A 2013; 110:21183-8. [PMID: 24248349 DOI: 10.1073/pnas.1311183110] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Cyclotides are plant peptides comprising a circular backbone and three conserved disulfide bonds that confer them with exceptional stability. They were originally discovered in Oldenlandia affinis based on their use in traditional African medicine to accelerate labor. Recently, cyclotides have been identified in numerous plant species of the coffee, violet, cucurbit, pea, potato, and grass families. Their unique structural topology, high stability, and tolerance to sequence variation make them promising templates for the development of peptide-based pharmaceuticals. However, the mechanisms underlying their biological activities remain largely unknown; specifically, a receptor for a native cyclotide has not been reported hitherto. Using bioactivity-guided fractionation of an herbal peptide extract known to indigenous healers as "kalata-kalata," the cyclotide kalata B7 was found to induce strong contractility on human uterine smooth muscle cells. Radioligand displacement and second messenger-based reporter assays confirmed the oxytocin and vasopressin V1a receptors, members of the G protein-coupled receptor family, as molecular targets for this cyclotide. Furthermore, we show that cyclotides can serve as templates for the design of selective G protein-coupled receptor ligands by generating an oxytocin-like peptide with nanomolar affinity. This nonapeptide elicited dose-dependent contractions on human myometrium. These observations provide a proof of concept for the development of cyclotide-based peptide ligands.
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Xu C, Long A, Fang X, Wood SL, Slater DM, Ni X, Olson DM. Effects of PGF2α on the expression of uterine activation proteins in pregnant human myometrial cells from upper and lower segment. J Clin Endocrinol Metab 2013; 98:2975-83. [PMID: 23678036 DOI: 10.1210/jc.2012-2829] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT The lower and upper segments of the uterus may play different roles in the process of parturition. The switch from pregnancy to delivery involves changes in expression of uterine activation proteins (UAPs). Prostaglandin (PG) F2α has multiple and complex roles in the birth process in addition to its vital contractile role. OBJECTIVE The purpose of this study was to investigate whether PGF2α regulates the expression of UAPs in human myometrium and to compare PGF2α actions in lower and upper segments. DESIGN Cultured human myometrial cells from upper and lower segments were treated with PGF2α. Western blotting was used to determine the levels of connexin 43 (CX-43), prostaglandin endoperoxide synthase-2 (PTGS-2; cyclooxygenase-2), oxytocin receptor (OTR), and PGF2α receptor (PTGFR) in the cells. The small interfering RNA approach was used to knock down PTGFR. RESULTS PGF2α dose dependently increased CX-43 and PTGS-2 while decreasing PTGFR in upper and lower segments. PGF2α increased OTR in the lower segment while decreasing it in the upper segment. PGF2α lost its effects on PTGS-2 and OTR in PTGFR knockdown cells, but its effect on CX-43 remained. AL8810, a specific antagonist of PTGFR, reversed the actions of PGF2α on UAPs except for CX-43 in the lower segment. Indomethacin reversed the PGF2α-induced effects on CX-43 and PTGS-2, but it did not alter PGF2α-induced PTGFR and OTR expression. The stimulatory effects of PGF2α were enhanced in the presence of IL-1β, which reversed the inhibitory effect of PGF2α on PTGFR. CONCLUSION PGF2α regulates UAPs in both upper and lower segment cells through either direct or indirect pathways, indicating that PGF2α uniquely participates in uterine preparation for the onset of labor.
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Affiliation(s)
- Chen Xu
- Department of Physiology and The Key Laboratory of Molecular Neurobiology of the Ministry of Education, Second Military Medical University, Shanghai, China 200433, USA
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Robinson H, Wray S. A new slow releasing, H₂S generating compound, GYY4137 relaxes spontaneous and oxytocin-stimulated contractions of human and rat pregnant myometrium. PLoS One 2012; 7:e46278. [PMID: 23029460 PMCID: PMC3459845 DOI: 10.1371/journal.pone.0046278] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 08/29/2012] [Indexed: 12/16/2022] Open
Abstract
Better tocolytics are required to help prevent preterm labour. The gaseotransmitter Hydrogen sulphide (H2S) has been shown to reduce myometrial contractility and thus is of potential interest. However previous studies used NaHS, which is toxic and releases H2S as a non-physiological bolus and thus alternative H2S donors are sought. GYY4137 has been developed to slowly release H2S and hence better reflect endogenous physiological release. We have examined its effects on spontaneous and oxytocin-stimulated contractility and compared them to NaHS, in human and rat myometrium, throughout gestation. The effects on contractility in response to GYY4137 (1 nM–1 mM) and NaHS (1 mM) were examined on myometrial strips from, biopsies of women undergoing elective caesarean section or hysterectomy, and from non-pregnant, 14, 18, 22 day (term) gestation or labouring rats. In pregnant rat and human myometrium dose-dependent and significant decreases in spontaneous contractions were seen with increasing concentrations of GYY4137, which also reduced underlying Ca transients. GYY4137 and NaHS significantly reduced oxytocin-stimulated and high-K depolarised contractions as well as spontaneous activity. Their inhibitory effects increased as gestation advanced, but were abruptly reversed in labour. Glibenclamide, an inhibitor of ATP-sensitive potassium (KATP) channels, abolished the inhibitory effect of GYY4137. These data suggest (i) H2S contributes to uterine quiescence from mid-gestation until labor, (ii) that H2S affects L-type calcium channels and KATP channels reducing Ca entry and thereby myometrial contractions, (iii) add to the evidence that H2S plays a physiological role in relaxing myometrium, and thus (iv) H2S is an attractive target for therapeutic manipulation of human myometrial contractility.
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Affiliation(s)
- Hayley Robinson
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Susan Wray
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
- * E-mail:
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Munglue P, Eumkep G, Wray S, Kupittayanant S. The effects of watermelon (Citrullus lanatus) extracts and L-citrulline on rat uterine contractility. Reprod Sci 2012; 20:437-48. [PMID: 22991380 DOI: 10.1177/1933719112459223] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In uterine smooth muscle, the effects of watermelon and its citrulline content are unknown. The aims of this study were therefore, to determine the effects of watermelon extract and citrulline on the myometrium and to investigate their mechanisms of action. The effects of extracts of watermelon flesh and rind and L-citrulline (64 μmol/L) were evaluated on 3 types of contractile activity; spontaneous, those elicited by potassium chloride (KCl) depolarization, or oxytocin (10 nmol/L) application in isolated rat uterus. Inhibitors of nitric oxide (NO) and its mechanisms of action, N ω-Nitro-L-arginine methyl ester hydrochloride (L-NAME, 100 μmol/L), LY83583 (1 μmol/L), and tetraethylamonium chloride (5 mmol/L), as well as Ca signaling pathways, were determined. Both flesh and rind extracts significantly decreased the force produced by all 3 mechanisms, in a dose-dependent manner. The extracts could also significantly decrease the force under conditions of sustained high Ca levels (depolarization and agonist) and when the force was produced only by sarcoplasmic reticulum (SR) Ca release. L-citrulline produced the same effects on force as watermelon extracts. With submaximal doses of extract, the additive effects of L-citrulline were found. The inhibitory effects of extracts and L-citrulline were reversed upon the addition of NO inhibitors, and pretreatment of tissues with these inhibitors prevented the actions of both extracts and L-citrulline. Thus, these data show that watermelon and citrulline are potent tocolytics, decreasing the force produced by calcium entry and SR release and arising by different pathways, including oxytocin stimulation. Their major mechanism is to stimulate the NO-cyclic guanosine monophosphate (cGMP) relaxant pathway.
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Affiliation(s)
- Phukphon Munglue
- Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
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Arrowsmith S, Quenby S, Weeks A, Burdyga T, Wray S. Poor spontaneous and oxytocin-stimulated contractility in human myometrium from postdates pregnancies. PLoS One 2012; 7:e36787. [PMID: 22590608 PMCID: PMC3349652 DOI: 10.1371/journal.pone.0036787] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 04/11/2012] [Indexed: 11/18/2022] Open
Abstract
Prolongation of pregnancy i.e. going more than 10 days over the estimated due date, complicates up to 10% of all pregnancies and is associated with increased risk to both mother and fetus. Despite the obvious need for contractions of the uterus to end pregnancy, there have been no studies directly examining the role of uterine smooth muscle, myometrium, in the aetiology of prolonged pregnancy. This study tested the hypothesis that the intrinsic contractile characteristics of myometrium taken from women with prolonged pregnancy (>41 weeks and 3 days) was reduced compared to those delivering at term (39–41 weeks). We recruited women undergoing Caesarean Section (CS) delivery either pre-labour (n = 27) or in labour (n = 66) at term or postdates. The contractile ability of the postdates myometrium, whether spontaneous or elicited by oxytocin or high-K solution, was significantly reduced compared to term myometrium. These differences remained when adjusted for parity and other maternal characteristics. The findings remained significant when expressed per cross sectional area. Histological examination revealed no differences between the two groups. The contractile differences were however related to intracellular Ca transients suggesting an effect of [Ca] on reduced force production in the postdates group. In summary, myometrium from prolonged pregnancies contracts poorly in vitro even when stimulated with oxytocin and in active labour. Responses to high K+ and measurements of Ca suggest that alterations in excitation contraction coupling, rather than any histological changes of the myometrium, may underlie the differences between term and postdates myometrium. We show that postdates pregnancy is associated with poor myometrial activity and suggest that this may contribute to increased myometrial quiescence and hence, prolonged gestation.
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Affiliation(s)
- Sarah Arrowsmith
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
- * E-mail:
| | - Siobhan Quenby
- Clinical Sciences Research Institute, University of Warwick, Warwick, United Kingdom
| | - Andrew Weeks
- Department of Women and Children's Health, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Theodor Burdyga
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Susan Wray
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
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Aslanidi O, Atia J, Benson A, van den Berg H, Blanks A, Choi C, Gilbert S, Goryanin I, Hayes-Gill B, Holden A, Li P, Norman J, Shmygol A, Simpson N, Taggart M, Tong W, Zhang H. Towards a computational reconstruction of the electrodynamics of premature and full term human labour. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2011; 107:183-92. [DOI: 10.1016/j.pbiomolbio.2011.07.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 07/05/2011] [Indexed: 01/02/2023]
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Quenby S, Matthew A, Zhang J, Dawood F, Wray S. In vitro myometrial contractility reflects indication for caesarean section. BJOG 2011; 118:1499-506. [PMID: 21790954 DOI: 10.1111/j.1471-0528.2011.03064.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To assess the extent to which in vitro measurements of myometrial contractility reflect the clinical indication for caesarean section. DESIGN A prospective, observational hypothesis-generating study. SETTING Women were recruited from Liverpool Women's NHS Foundation Trust and experiments were performed in the Physiology Department at the University of Liverpool. POPULATION Myometrial samples were taken from women undergoing a caesarean section during labour (n = 50) or from women having a repeat nonlabouring caesarean section (n = 70). METHODS The demographic characteristics of the women and indications for current and previous caesarean sections were recorded. The force, frequency and duration of spontaneous contractions of myometrial strips, and changes in the intracellular calcium concentration of the strips, were measured. Kruskall-Wallis and post hoc tests were used to assess the significance of differences between groups. RESULTS Samples from women whose caesarean section was for fetal distress/acidosis (scalp pH <7.2) contracted with more force than those from women whose caesarean section was for delay in the first stage of labour (P < 0.001). For repeat, nonlabouring caesarean sections, samples from women whose first caesarean section was for fetal distress/acidosis also contracted with more force than did samples from women whose first caesarean section was for delay in the first stage of labour (P = 0.03). CONCLUSIONS These findings suggest that the myometrium contracts with greater force in women who have a caesarean section for fetal distress.
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Affiliation(s)
- S Quenby
- Clinical Sciences Research Institute, University of Warwick, Coventry, UK.
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Lijuan W, Kupittayanant P, Chudapongse N, Wray S, Kupittayanant S. The Effects of Wild Ginger (Costus speciosus (Koen) Smith) Rhizome Extract and Diosgenin on Rat Uterine Contractions. Reprod Sci 2011; 18:516-24. [DOI: 10.1177/1933719110391278] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Wanwisa Lijuan
- Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Pakanit Kupittayanant
- Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Nuannoi Chudapongse
- Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Susan Wray
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Sajeera Kupittayanant
- Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
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Turton P, Neilson JP, Quenby S, Burdyga T, Wray S. A short review of twin pregnancy and how oxytocin receptor expression may differ in multiple pregnancy. Eur J Obstet Gynecol Reprod Biol 2009; 144 Suppl 1:S40-4. [DOI: 10.1016/j.ejogrb.2009.02.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Burdyga T, Borisova L, Burdyga AT, Wray S. Temporal and spatial variations in spontaneous Ca events and mechanical activity in pregnant rat myometrium. Eur J Obstet Gynecol Reprod Biol 2009; 144 Suppl 1:S25-32. [PMID: 19282086 DOI: 10.1016/j.ejogrb.2009.02.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
OBJECTIVES The aim of this study was to investigate the temporal and spatial characteristics of spontaneous Ca signals in pregnant rat myometrium. STUDY DESIGN Confocal imaging of longitudinal strips of 21-day pregnant rats loaded with the Ca sensitive indicator Fluo-4, was combined with measurements of mechanical activity in uterine smooth muscle cells, in situ and freshly isolated. RESULTS Our results show that the Ca transients in pregnant uterine tissue are composed of Ca spikes, which are associated with the spike-like action potentials. There is large variation in the pattern of spontaneous activity in myometrium, ranging from non-propagating Ca spikes confined to individual smooth muscle cells, through to regional and global propagating Ca spikes. Irrespective of the pattern of activity displayed, the Ca signals were always in the form of Ca spikes, singularly or in bursts. These Ca spikes did not show fixed initiations sites, propagated in longitudinal and transverse directions from the initiation regions, and had a variable pattern of propagation in preparations which were not synchronously active. In preparations which showed synchronous activity, Ca spikes singularly or bursts propagated mainly in the transverse direction from the initiation regions. The amplitude of force generated by single spikes was dependent on the number of bundles recruited by the propagating Ca spike within the strip, and was about 30-40% of the maximal force produced by carbachol or high-K stimulation. If Ca spikes appeared in the form of bursts they generated longer lasting fused contractions, the amplitudes of which were dependent on the number and the frequency of Ca spikes in the burst. CONCLUSIONS Longitudinal myometrium from pregnant rats generates spontaneous Ca spikes which vary in their initiation sites, spatial spread and frequency and are associated with the spike-like action potentials. They are sensitive to the L-type Ca channel blocker, nifedipine. Contractile activity was dependent on the spatial spread of individual Ca spikes and when fully synchronized, produced single submaximal phasic contraction. The number and frequency of bursts of Ca spikes controlled the amplitude and duration of contraction.
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Affiliation(s)
- Theodor Burdyga
- Department of Physiology, School of Biomedical Sciences, University of Liverpool, Crown Street, Liverpool L693BX, UK.
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Noble K, Matthew A, Burdyga T, Wray S. A review of recent insights into the role of the sarcoplasmic reticulum and Ca entry in uterine smooth muscle. Eur J Obstet Gynecol Reprod Biol 2009; 144 Suppl 1:S11-9. [PMID: 19285773 DOI: 10.1016/j.ejogrb.2009.02.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The uterine sacroplasmic reticulum (SR) takes up and stores calcium [Ca], using an ATPase (SERCA) and the Ca-buffering proteins, calsequestrin and calreticulin. This stored Ca can be released via IP(3)-gated Ca channels. Decreases in luminal Ca concentration [Ca] have been directly measured following agonist stimulation. During spontaneous contractions however, there appears to be no involvement of the SR, as Ca entry and efflux across the plasma membrane account for these phasic contractions. After over-viewing current knowledge concerning SR structure and function, we highlight three areas of research which suggest new ways of looking at the role of the SR in the uterus, although they may be controversial or speculative at the moment. Firstly, we review the evidence for the function, if any, of Ca-induced SR Ca release channels, the ryanodine receptor (RyR) and the lack of Ca sparks (the elemental release events from RyRs), in the uterus. Secondly, we ask does regulation of SERCA by the accessory protein, phospholamban, occur in the uterus and what is the effect of knocking out phospholamban on uterine activity? Thirdly, we address the question of when and how store-operated Ca entry occurs in the myometrium. By analogy with other, usually less excitable tissues, is there a mechanism that links store Ca depletion to plasma membrane Ca entry in smooth muscle cells within intact uterus and is it physiologically relevant and regulated? Are the recently described proteins ORAI and STIM-1 involved in uterine store-operated Ca entry? We end the review by integrating these new insights with previous data to present a new working model of the SR in the uterus.
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Affiliation(s)
- Karen Noble
- Department of Physiology, School of Biomedical Sciences, University of Liverpool, Crown Street, Liverpool L693BX, UK
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Kupittayanant S, Kupittayanant P, Suwannachat C. Mechanisms of uterine contractility in laying hens. Anim Reprod Sci 2008; 115:215-24. [PMID: 19081211 DOI: 10.1016/j.anireprosci.2008.10.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2008] [Revised: 10/20/2008] [Accepted: 10/23/2008] [Indexed: 10/21/2022]
Abstract
The physiological basis of uterine contractility in laying hens is not well understood, but a better understanding is important for understanding the mechanisms governing egg laying. The characteristics of uterine contractility arising spontaneously or by prostaglandin F(2alpha) (PGF(2alpha)) stimulation were therefore examined and the underlying mechanisms investigated. Uterine strips were isolated from laying hens 4h before oviposition and force measured. These strips remained healthy in vitro and produced regular spontaneous contractions. The contractions were phasic and could be recorded for several hours. Exposure to nifedipine, the specific L-type Ca channel blocker, led to the abolition of force. The contraction amplitude and frequency were significantly increased when Bay K8644, an agonist of L-type Ca channels, was applied or when the concentration of extracellular Ca was elevated. Spontaneous contractions were also significantly inhibited by wortmannin, the specific inhibitor of myosin light chain kinase (MLCK). When 1 microM PGF(2alpha) was applied to spontaneously contracting uterus, it significantly increased their amplitude and frequency of the contractions. As with spontaneous contractions, PGF(2alpha)-induced force production was abolished by nifedipine and wortmannin. In the absence of extracellular Ca, a small but tonic force was generated upon application of PGF(2alpha) which was not affected by wortmannin. Thus, extracellular Ca entry and MLCK phosphorylation are essential for uterine force production occurring spontaneously or by PGF(2alpha) stimulation. Our data supports the conclusion that the pathway dependent on extracellular Ca entry and MLCK phosphorylation predominates during PGF(2alpha) stimulation but suggests some involvement of an alternative force-producing pathway, presumably Ca-sensitization.
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Affiliation(s)
- S Kupittayanant
- School of Physiology, Institute of Science, Suranaree University of Technology, University Avenue, Nakhon Ratchasima 30000, Thailand.
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Wray S, Noble K. Sex hormones and excitation-contraction coupling in the uterus: the effects of oestrous and hormones. J Neuroendocrinol 2008; 20:451-61. [PMID: 18266942 DOI: 10.1111/j.1365-2826.2008.01665.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this review, we examine how far the increased understanding that we have of the events in excitation contraction can explain the effects of the oestrous cycle and sex hormones on uterine function. Observational studies of electrical and mechanical activity in the rat myometrium have shown a relative quiescence during pro-oestrous, with little propagation of any electrical events. Thus, uterine activity can be said to approximately inversely reflect plasma 17beta-oestradiol concentrations. We show that Ca(2+) signalling and mechanical activity are greatest in metoestrous and dioestrous compared to pro-oestrous and oestrous. These data are discussed in terms of hormonal effects on Ca(2+) and K(+) channels. Finally, the influence of sex hormones on lipid rafts and caveolae are considered and discussed in relation to recent findings on their role in uterine signalling and contractility, and cholesterol levels and obesity.
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Affiliation(s)
- S Wray
- The Physiological Department, School of Biomedical Sciences, University of Liverpool, Liverpool, UK.
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Kendrick A, Quenby S, Wray S. Contractility and calcium signaling of human myometrium are profoundly affected by cholesterol manipulation: implications for labor? Reprod Sci 2007; 14:456-66. [PMID: 17913965 DOI: 10.1177/1933719107306229] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The authors elucidate cholesterol's effect on human uterine contractility and calcium signaling to test the hypotheses that elevation of cholesterol decreases uterine activity and that oxytocin cannot augment contraction when cholesterol is elevated. The effects of cholesterol extraction with methyl beta-cyclodextrin and enrichment with low-density lipoproteins and cholesterol on contractile activity and intracellular calcium signaling in spontaneous or oxytocin-stimulated myometrium are determined. Force occurring spontaneously and with oxytocin is significantly increased by cholesterol extraction. Cholesterol enrichment profoundly inhibits force production in a dose-dependent manner and could reverse the effects of cholesterol extraction. Qualitatively similar results are found for nonpregnant and pregnant laboring and non-laboring myometrium. These contractile changes are related to changes in intracellular Ca2+ . Thus, elevated cholesterol is deleterious to contractility and Ca2+ signaling in human myometrium. Cholesterol may contribute to uterine quiescence but could cause difficulties in labor in obese/dyslipidemic women, consistent with their increased cesarean delivery rates.
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Abstract
A better understanding of the mechanisms that generate and modulate uterine contractility is needed if progress is to be made in the prevention or treatment of problems in labour. Dysfunctional labour describes the condition when uterine contractility is too poor to dilate the cervix, and it is the leading cause of emergency Caesarean sections. Recently, insight has been gained into a possible causal mechanism for dysfunctional labour. Study of the physiological mechanisms that produce excitation in the uterus, the subsequent Ca(2)(+) signals and biochemical pathway leading to contraction has underpinned this progress. In this review, I give an account of excitation-contraction signalling in the myometrium and explore the implications of recent findings concerning lipid rafts for these processes. I also discuss how changes of pH are fundamentally enmeshed in uterine activity and biochemistry and explore the effect that pH changes will have on human myometrium. Finally, I present the evidence that acidification of the myometrium is correlated with dysfunctional labour and suggest the processes by which it is occurring. It is only by gaining a better understanding of uterine physiology and pathophysiology that progress will be made and research findings translated into clinical benefit for women and their families.
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Affiliation(s)
- Susan Wray
- Department of Physiology, University of Liverpool, Crown Street, Liverpool L69 3BX, UK.
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