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Affiliation(s)
- G Kinman
- School of Psychology, University of Bedfordshire, Luton, UK
| | - S Wray
- York Business School, York St. John University, York, UK
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Preza E, Hardy J, Warner T, Wray S. Review: Induced pluripotent stem cell models of frontotemporal dementia. Neuropathol Appl Neurobiol 2017; 42:497-520. [PMID: 27291591 DOI: 10.1111/nan.12334] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 06/09/2016] [Accepted: 06/13/2016] [Indexed: 12/11/2022]
Abstract
The increasing prevalence of dementia in the ageing population combined with the lack of treatments and the burden on national health care systems globally make dementia a public health priority. Despite the plethora of important research findings published over the past two decades, the mechanisms underlying dementia are still poorly understood and the progress in pharmacological interventions is limited. Recent advances in cellular reprogramming and genome engineering technologies offer an unprecedented new paradigm in disease modeling. Induced pluripotent stem cells (iPSCs) have enabled the study of patient-derived neurons in vitro, a significant progress in the field of dementia research. The first studies using iPSCs to model dementia have recently emerged, holding promise for elucidating disease pathogenic mechanisms and accelerating drug discovery. In this review, we summarize the major findings of iPSC-based studies in frontotemporal dementia (FTD) and FTD overlapping with amyotrophic lateral sclerosis (FTD/ALS). We also discuss some of the main challenges in the use of iPSCs to model complex, late-onset neurodegenerative diseases such as dementias.
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Affiliation(s)
- E Preza
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 1PJ, UK.
| | - J Hardy
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 1PJ, UK
| | - T Warner
- Reta Lila Weston Institute of Neurological Studies, UCL Institute of Neurology, London, WC1N 1PJ, UK
| | - S Wray
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 1PJ, UK
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Arber CE, Li A, Houlden H, Wray S. Review: Insights into molecular mechanisms of disease in neurodegeneration with brain iron accumulation: unifying theories. Neuropathol Appl Neurobiol 2016; 42:220-41. [PMID: 25870938 PMCID: PMC4832581 DOI: 10.1111/nan.12242] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 03/18/2015] [Indexed: 12/14/2022]
Abstract
Neurodegeneration with brain iron accumulation (NBIA) is a group of disorders characterized by dystonia, parkinsonism and spasticity. Iron accumulates in the basal ganglia and may be accompanied by Lewy bodies, axonal swellings and hyperphosphorylated tau depending on NBIA subtype. Mutations in 10 genes have been associated with NBIA that include Ceruloplasmin (Cp) and ferritin light chain (FTL), both directly involved in iron homeostasis, as well as Pantothenate Kinase 2 (PANK2), Phospholipase A2 group 6 (PLA2G6), Fatty acid hydroxylase 2 (FA2H), Coenzyme A synthase (COASY), C19orf12, WDR45 and DCAF17 (C2orf37). These genes are involved in seemingly unrelated cellular pathways, such as lipid metabolism, Coenzyme A synthesis and autophagy. A greater understanding of the cellular pathways that link these genes and the disease mechanisms leading to iron dyshomeostasis is needed. Additionally, the major overlap seen between NBIA and more common neurodegenerative diseases may highlight conserved disease processes. In this review, we will discuss clinical and pathological findings for each NBIA-related gene, discuss proposed disease mechanisms such as mitochondrial health, oxidative damage, autophagy/mitophagy and iron homeostasis, and speculate the potential overlap between NBIA subtypes.
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Affiliation(s)
- C E Arber
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London, UK
| | - A Li
- Reta Lila Weston Institute, Institute of Neurology, University College London, London, UK
| | - H Houlden
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London, UK
| | - S Wray
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London, UK
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Wray S, Burdyga T, Noble D, Noble K, Borysova L, Arrowsmith S. Progress in understanding electro-mechanical signalling in the myometrium. Acta Physiol (Oxf) 2015; 213:417-31. [PMID: 25439280 DOI: 10.1111/apha.12431] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 11/11/2014] [Accepted: 11/17/2014] [Indexed: 11/30/2022]
Abstract
In this review, we give a state-of-the-art account of uterine contractility, focussing on excitation-contraction (electro-mechanical) coupling (ECC). This will show how electrophysiological data and intracellular calcium measurements can be related to more modern techniques such as confocal microscopy and molecular biology, to advance our understanding of mechanical output and its modulation in the smooth muscle of the uterus, the myometrium. This new knowledge and understanding, for example concerning the role of the sarcoplasmic reticulum (SR), or stretch-activated K channels, when linked to biochemical and molecular pathways, provides a clearer and better informed basis for the development of new drugs and targets. These are urgently needed to combat dysfunctions in excitation-contraction coupling that are clinically challenging, such as preterm labour, slow to progress labours and post-partum haemorrhage. It remains the case that scientific progress still needs to be made in areas such as pacemaking and understanding interactions between the uterine environment and ion channel activity.
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Affiliation(s)
- S. Wray
- Department of Cellular and Molecular Physiology; Institute of Translational Medicine; University of Liverpool; Liverpool Women's Hospital; Liverpool UK
| | - T. Burdyga
- Department of Cellular and Molecular Physiology; Institute of Translational Medicine; University of Liverpool; Liverpool Women's Hospital; Liverpool UK
| | - D. Noble
- Department of Cellular and Molecular Physiology; Institute of Translational Medicine; University of Liverpool; Liverpool Women's Hospital; Liverpool UK
| | - K. Noble
- Department of Cellular and Molecular Physiology; Institute of Translational Medicine; University of Liverpool; Liverpool Women's Hospital; Liverpool UK
| | - L. Borysova
- Department of Cellular and Molecular Physiology; Institute of Translational Medicine; University of Liverpool; Liverpool Women's Hospital; Liverpool UK
| | - S. Arrowsmith
- Department of Cellular and Molecular Physiology; Institute of Translational Medicine; University of Liverpool; Liverpool Women's Hospital; Liverpool UK
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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: 165] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Wada E, Battey J, Wray S. Bombesin Receptor Gene Expression in Rat Embryos: Transient GRP-R Gene Expression in the Posterior Pituitary. Mol Cell Neurosci 2012; 4:13-24. [PMID: 19912903 DOI: 10.1006/mcne.1993.1002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Bombesin-like peptides can stimulate growth of cultured cells derived from ectoderm, endoderm, or mesenchyme and act as autocrine growth factors in some lung carcinoma cell lines. Recently, cDNA clones for two mammalian bombesin receptors (BN-R), gastrin-releasing peptide receptor (GRP-R) and neuromedin B receptor (NMB-R), were characterized and shown to be present in distinct regions of the central nervous system at birth. To determine whether the spatial and/or temporal expression of BN-R genes correlated with tissue-specific or organ-specific developmental events, the prenatal distribution of GRP-R and NMB-R mRNAs were compared by in situ hybridization histochemistry. The differential expression of these two BN-R genes was striking. From early embryonic stages, GRP-R mRNA was expressed in various organs, including nervous, urogenital, respiratory, and digestive systems. In contrast, NMB-R gene expression was detected at later embryonic stages and the distribution of expression was much more limited. In most tissues, after onset of expression, both receptor mRNAs showed a steady increase in expression throughout development. However, transient expression of GRP-R mRNA was seen in the posterior pituitary. Intense GRP-R labeling of posterior pituitary cells was seen from E12 to E20, but at birth, GRP-R mRNA levels were undetectable. These results suggest that (a) two BN-R subtypes mediate independent functions during development, (b) ontogenesis of multiple organs may involve GRP-R mediated events, and (c) GRP-R gene expression is involved in differentiation/development of the pituitary gland.
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Affiliation(s)
- E Wada
- Laboratory of Neurochemistry, NINDS, NIH, Bethesda, Maryland 20892; and Laboratory of Biological Chemistry, DTP, DCT, NCI, Bethesda, Maryland 20892
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Zhang X, Tao Y, Chopra M, Troiani L, Marcus K, Choudhary N, Wray S, Krolczyk S, Markovic-Plese S. Alemtuzumab (Anti-CD52 mAb) Induces Expansion of Treg and Th2 Cells and Inhibits Th1 and Th17 Cells in Treated Patients with Relapsing Remitting Multiple Sclerosis (RRMS) (P02.119). Neurology 2012. [DOI: 10.1212/wnl.78.1_meetingabstracts.p02.119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Al-Qahtani S, Heath A, Quenby S, Dawood F, Floyd R, Burdyga T, Wray S. Diabetes is associated with impairment of uterine contractility and high Caesarean section rate. Diabetologia 2012; 55:489-98. [PMID: 22101974 PMCID: PMC3245824 DOI: 10.1007/s00125-011-2371-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 10/13/2011] [Indexed: 01/23/2023]
Abstract
AIMS/HYPOTHESIS The prevalence of births worldwide complicated by diabetes mellitus is increasing. In the UK, for example, <25% of diabetic women have a non-instrumental vaginal delivery. Strikingly, more than half the Caesarean sections (CS) in these patients are non-elective, but the reasons for this are not understood. We have tested the hypothesis that poor myometrial contractility as a consequence of the disease contributes to this high CS rate. METHODS We compared spontaneous, high K depolarisation and oxytocin-induced contractions from diabetic and matched control patients having an elective CS. To investigate the mechanism of any differences we measured intracellular Ca, and performed western blotting and compared the tissues histologically. RESULTS There was significantly decreased contraction amplitude and duration in uteri from diabetic compared with control patients, even when possible confounders such as BMI were analysed. Reduced intracellular calcium signals and expression of calcium entry channels were found in uteruses from diabetic patients, which, along with a reduction in muscle content found on histological examination, could explain the reduced force. Myometrium from diabetic patients was responsive to oxytocin, but still did not reach the levels found in non-diabetic patients. CONCLUSIONS/INTERPRETATIONS These are the first data investigating myometrium in diabetic patients and they support the hypothesis that there is poorer contractility even in the presence of oxytocin. The underlying mechanism is related to reduced Ca channel expression and intracellular calcium signals and a decrease in muscle mass. We conclude that these factors significantly contribute to the increased emergency CS rate in diabetic patients.
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Affiliation(s)
- S. Al-Qahtani
- Department of Molecular and Cellular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX UK
- Department of Physiology, Medical College, Jazan University, Jazan, Kingdom of Saudi Arabia
| | - A. Heath
- Department of Molecular and Cellular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX UK
| | - S. Quenby
- Liverpool Women’s Hospital, University of Liverpool, Liverpool, UK
- Present Address: Clinical Sciences Research Institute, University of Warwick, Coventry, UK
| | - F. Dawood
- Liverpool Women’s Hospital, University of Liverpool, Liverpool, UK
| | - R. Floyd
- Department of Molecular and Cellular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX UK
| | - T. Burdyga
- Department of Molecular and Cellular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX UK
| | - S. Wray
- Department of Molecular and Cellular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX UK
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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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Abstract
OBJECTIVE To investigate the effect of maternal obesity on mode of delivery following induction of labour (IOL) for prolonged pregnancy and subsequent intrapartum and neonatal complications. DESIGN Retrospective (historical) cohort study. SETTING Liverpool Women's Hospital NHS Foundation Trust, UK. POPULATION A total of 29, 224 women with singleton pregnancies between 2004 and 2008 of whom 3076 had a prolonged pregnancy (defined as ≥290 days or 41(+3) weeks of gestation) and received IOL. METHODS Kruskal-Wallis test, chi-square test and multivariable logistic regression. MAIN OUTCOME MEASURES Mode of delivery and risk of delivery and neonatal complications in obese verses non-obese women following IOL. RESULTS Obese women had a significantly higher rate of IOL ending in caesarean section compared with women of normal weight following IOL (38.7% versus 23.8% primiparous; 9.9% versus 7.9% multiparous women, respectively); however, length of labour, incidence of postpartum haemorrhage and third-degree tear, rate of low cord blood pH, low Apgar scores and shoulder dystocia were similar in all body mass index categories. Complications included a higher incidence of fetal macrosomia and second-degree, but not third-degree, tear in primiparous women. CONCLUSIONS Higher maternal body mass index at booking is associated with an increased risk of prolonged pregnancy and increased rate of IOL. Despite this, more than 60% of obese primiparous and 90% of multiparous women with prolonged pregnancies who were induced achieved vaginal delivery and labour complications in the obese women with prolonged pregnancies were largely comparable to those of normal weight women with prolonged pregnancies. Our data suggest that IOL for prolonged pregnancy in obese women is a reasonable and safe management option.
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Affiliation(s)
- S Arrowsmith
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, UK.
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Abstract
Gonadotrophin-releasing hormone-1 (GnRH-1) is essential for mammalian reproduction, controlling release of gonadotrophins from the anterior pituitary. GnRH-1 neurones migrate from the nasal placode into the forebrain during development. Although first located within the nasal placode, the embryonic origin/lineage of GnRH-1 neurones is still unclear. The migration of GnRH-1 cells is the best characterised example of neurophilic/axophilic migration, with the cells using a subset of olfactory-derived vomeronasal axons as their pathway and numerous molecules to guide their movement into the forebrain. Exciting work in this area is beginning to identify intersecting pathways that orchestrate the movement of these critical neuroendocrine cells into the central nervous system, both spatially and temporally, through a diverse and changing terrain. Once within the forebrain, little is known about how the axons target the median eminence and ultimately secrete GnRH-1 in a pulsatile fashion.
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Affiliation(s)
- S Wray
- Cellular and Developmental Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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Delpy DT, Cope MC, Cady EB, Wyatt JS, Hamilton PA, Hope PL, Wray S, Reynolds EOR. Cerebral monitoring in newborn infants by magnetic resonance and near infrared spectroscopy. Scandinavian Journal of Clinical and Laboratory Investigation 2010. [DOI: 10.1080/00365518709168165] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Dawood F, Quenby S, Wray S. P752 Myometrial contractility patterns in endometriosis compared to menorrhagia. Int J Gynaecol Obstet 2009. [DOI: 10.1016/s0020-7292(09)62243-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Hennebry M, Stocks G, Belavadi P, Barnes J, Wray S, Columb M, Lyons G. Effect of i.v. phenylephrine or ephedrine on the ED50 of intrathecal bupivacaine with fentanyl for Caesarean section. Br J Anaesth 2009; 102:806-11. [DOI: 10.1093/bja/aep095] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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Affiliation(s)
- F. Casoni
- National Institute of Neurological Disorder and StrokeCellular and developmental Neurobiology SectionUSA
| | - S. Wray
- National Institute of Neurological Disorder and StrokeCellular and developmental Neurobiology SectionUSA
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Affiliation(s)
- C W Bain
- Cardiographic Department, Harrogate General Hospital
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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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Abstract
Gonadotrophin-releasing hormone (GnRH-1) neurones reside in the forebrain and regulate gonadal function via the hypothalamic-pituitary-gonadal axis. Disruption of this axis results in reproductive dysfunction. During embryonic development, GnRH-1 neurones migrate from the nasal pit through the nasal/forebrain junction (NFJ) into the developing brain. Prenatally gamma-aminobutyric acid (GABA) is excitatory and has been shown to play a role in nervous system development. Both in vivo and in vitro experiments suggest that GABA inhibits migration of GnRH-1 neurones. The present study examines the migration of GnRH-1 neurones in GAD67 knockout (KO) mice to further elucidate the role of GABA on GnRH-1 neuronal development. Three stages were examined, embryonic day (E)12.5, E14.5 and E17.5. GnRH-1 cell number and location were analysed by immunocytochemistry and in situ hybridisation histochemistry. The total number of GnRH-1 immunopositive cells was similar between wild-type (WT) and KO mice. However, significant differences were found in the overall distribution of GnRH-1 immunopositive cells in GAD67 KO compared to WT mice at all stages. Subsequent analysis by area revealed differences occurred at the NFJ with an increase in GnRH-1 cells in GAD67 KO at E14.5 and a decrease in GnRH-1 cells in GAD67 KO at E17.5. Comparable counts for cells expressing GnRH-1 transcript and protein were obtained. These data indicate that attenuated levels of GABA accelerate GnRH-1 cell migration in nasal areas as well as movement of GnRH-1 cells into the central nervous system at the NFJ.
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Affiliation(s)
- J M Lee
- Cellular and Developmental Neurobiology Section, National Institute of Neurological Disorder and Stroke, National Institutes of Health, Bethesda, MD, USA
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Abstract
The use of general anaesthesia for dental treatment in the NHS outside hospitals has changed over time. Although deaths are uncommon during or immediately after general anaesthesia for dental treatment, they are more likely to occur than with other methods of pain and anxiety reduction, such as local anaesthesia and conscious sedation. Inquiries into recent anaesthetic deaths in dental practice have been critical of the standard of care provided in areas such as pre-operative assessment, monitoring, resuscitation and transfer to specialist critical care facilities.
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Affiliation(s)
- M S Mikhael
- Barking, Havering and Redbridge Hospitals Associate University NHS Trust.
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Abstract
A novel protein (NELF) was identified screening embryonic luteinizing hormone releasing hormone (LHRH) neurons at different migrational states. Experiments in vitro revealed that NELF functions in olfactory axon outgrowth and subsequently alters LHRH neuronal migration. NELF was not restricted to LHRH neurons in the developing rodent. Multiple CNS and PNS tissues expressed this gene. To characterize the specific regions that express NELF in situ hybridization histochemistry was performed. Within the CNS, cells in the cortex, hippocampus, thalamus and olfactory regions express NELF pre- and postnatally.
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Affiliation(s)
- P R Kramer
- Cellular and Developmental Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
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Abstract
OBJECTIVE The aim of the study was to elucidate the reason for the high rate of caesarean section in obese women. We examined the following hypotheses: (1) obese women have a high incidence of complications related to poor uterine contractility--caesarean section for dysfunctional labour and postpartum haemorrhage. 2) The myometrium from obese women has less ability to contract in vitro. DESIGN First, a clinical retrospective analysis of data from 3913 completed singleton pregnancies was performed. Secondly, in a prospective study the force, frequency and intracellular [Ca(2+)] flux of spontaneously contracting myometrium were related to the maternal body mass index. SETTING Liverpool Women's Hospital and University of Liverpool. POPULATION The clinical study involved all women who delivered in one hospital in 2002. The in vitro study myometrial biopsies were obtained from 73 women who had elective caesarean section at term. RESULTS Maternal obesity carried significant risk of caesarean section in labour that was highest for delay in the first stage of labour (OR 3.54). The increased risk of caesarean section in obese women largely occurred in women with normal- and not with high-birthweight infants. Obese women delivering vaginally had increased risk of prolonged first stage of labour and excessive blood loss. Myometrium from obese women contracted with less force and frequency and had less [Ca(2+)] flux than that from normal-weight women. CONCLUSIONS We suggest that these findings indicate that obesity may impair the ability of the uterus to contract in labour.
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Affiliation(s)
- J Zhang
- Department of Physiology, University of Liverpool, Liverpool, UK
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Dubuis E, Rockliffe N, Hussain M, Boyett M, Wray S, Gawler D. c-Src-mediated phosphorylation of cardiac L-type Ca2+ channel regulates ICa through multiple binding sites. J Mol Cell Cardiol 2006. [DOI: 10.1016/j.yjmcc.2006.03.195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Borisova L, Eisner D, Wray S, Burdyga T. Calcium signalling and vasomotion in pre-capillary arterioles differs from that in arteries. J Mol Cell Cardiol 2006. [DOI: 10.1016/j.yjmcc.2006.03.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Burdyga T, Wray S. In situ Ca2+ signalling in pregnant rat uterine smooth muscle cells. J Biomech 2006. [DOI: 10.1016/s0021-9290(06)84353-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Abstract
The objective of this investigation was to use semi-quantitative immunohistochemistry to determine the distribution and expression levels of AQP2 and AQP3 proteins in normal human Tissue MicroArrays. Expression of the vasopressin regulated AQP2 was observed in a limited number of tissues. AQP2 was prominent in the apical and subapical plasma membranes of cortical and medullary renal collecting ducts. Surprisingly, weak AQP2 immunoreactivity was also noted in pancreatic islets, fallopian tubes and peripheral nerves. AQP2 was also localized to selected parts of the central nervous system (ependymal cell layer, subcortical white matter, hippocampus, spinal cord) and selected cells in the gastrointestinal system (antral and oxyntic gastric mucosa, small intestine and colon). These findings corroborate the restricted tissue distribution of AQP2. AQP3 was strongly expressed in many of the human tissues examined particularly in basolateral membranes of the distal nephron (medullary collecting ducts), distal colon, upper airway epithelia, transitional epithelium of the urinary bladder, tracheal, bronchial and nasopharyngeal epithelium, stratified squamous epithelial cells of the esophagus, and anus. AQP3 was moderately expressed in basolateral membranes of prostatic tubuloalveolar epithelium, pancreatic ducts, uterine endometrium, choroid plexus, articular chondrocytes, subchondral osteoblasts and synovium. Low AQP3 levels were also detected in skeletal muscle, cardiac muscle, gastric pits, seminiferous tubules, lymphoid vessels, salivary and endocrine glands, amniotic membranes, placenta and ovary. The abundance of basolateral AQP3 in epithelial tissues and its expression in many non-epithelial cells suggests that this aquaglyceroporin is a major participant in barrier hydration and water and osmolyte homeostasis in the human body.
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Affiliation(s)
- A Mobasheri
- Connective Tissue and Molecular Pathogenesis Research Groups, Faculty of Veterinary Science, University ofLiverpool, Liverpool, L69 7ZJ, UK
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Abstract
It is becoming increasingly evident that GABA plays an important role in the regulation of gonadotrophin-releasing hormone (GnRH)-1 neurones via the GABAA receptor. The aim of the present study was to characterise expression of the GABAA receptor within the GnRH-1 system across development. The expression pattern of five GABAAalpha subunits and one GABAAbeta subunit was first examined within individual GnRH-1 neurones by the polymerase chain reaction. A significant increase in the expression of GABAAalpha2 and a significant decrease in the expression of GABAAalpha6 over time were found. Of the other subunits examined, two (alpha1 and alpha3) showed no differences in expression and two (alpha4 and beta3) showed variable low incidence of expression. Given the reciprocal relationship of alpha2 and alpha6 expression, we hypothesised that there is a developmental switch in the expression of these subunits in GnRH-1 neurones. To investigate this hypothesis, single- and double-label immunocytochemistry for GABAAalpha2 and alpha6 and GnRH-1 was performed in tissue from ages E12.5 to adulthood, as well as in nasal explants. We show that GABAAalpha2 and alpha6 are present in the GnRH-1 neuronal system both in vivo and in vitro and that the levels of expression are altered as a function of age.
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Affiliation(s)
- J L Temple
- National Institute of Neurological Disorders and Stroke, Cellular and Developmental Neurobiology Section, Bethesda, MD 20892, USA
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Affiliation(s)
- D Wray
- Barwick in Elmet, Leeds, UK.
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Babiychuk EB, Smith RD, Burdyga T, Babiychuk VS, Wray S, Draeger A. Membrane Cholesterol Regulates Smooth Muscle Phasic Contraction. J Membr Biol 2004; 198:95-101. [PMID: 15138749 DOI: 10.1007/s00232-004-0663-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2003] [Revised: 12/18/2003] [Indexed: 10/26/2022]
Abstract
The regulation of contractile activity in smooth muscle cells involves rapid discrimination and processing of a multitude of simultaneous signals impinging on the membrane before an integrated functional response can be generated. The sarcolemma of smooth muscle cells is segregated into caveolar regions-largely identical with cholesterol-rich membrane rafts-and actin-attachment sites, localized in non-raft, glycerophospholipid regions. Here we demonstrate that selective extraction of cholesterol abolishes membrane segregation and disassembles caveolae. Simultaneous measurements of force and [Ca2+]i in rat ureters demonstrated that extraction of cholesterol resulted in inhibition of both force and intracellular Ca2+ signals. Considering the major structural reorganization of cholesterol-depleted sarcolemma, it is intriguing to note that decreased levels of membrane cholesterol are accompanied by a highly specific inhibition of phasic, but not tonic contractions. This implies that signalling cascades that ultimately lead to either phasic or tonic response may be spatially segregated in the plane of the sarcolemma. Replenishment of cholesterol restores normal contractile behavior. In addition, the tissue function is re-established by inhibiting the large-conductance K(+)-channel. Sucrose gradient ultracentrifugation in combination with Western blotting analysis demonstrates that its alpha-subunit is associated with detergent-resistant membranes, suggesting that the channel might be localized within the membrane rafts in vivo. These findings are important in understanding the complex signalling pathways in smooth muscle and conditions such as premature labor and hypertension.
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Affiliation(s)
- E B Babiychuk
- Department of Cell Biology, Institute of Anatomy, University of Bern, Bern 9, CH, 3000, Switzerland.
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Pierce SJ, Monir-Bishty E, Wray S. Comparison of the effects of hypoxia and acidification on human myometrium: a common mechanism of action? J OBSTET GYNAECOL 2003. [DOI: 10.1080/713938768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Quenby SM, Pierce SJ, Brigham S, Wray S. Myometrial lactic acidosis is a significant cause of dysfunctional labour. J OBSTET GYNAECOL 2003. [DOI: 10.1080/718591781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Abstract
Obstructed labour is an important cause of maternal deaths in communities in which undernutrition in childhood is common resulting in small pelves in women, and in which there is no easy access to functioning health facilities with the capability of carrying out operative deliveries. Obstructed labour also causes significant maternal morbidity in the short term (notably infection) and long term (notably obstetric fistulas). Fetal death from asphyxia is also common. There are differences in the behaviour of the uterus during obstructed labour, depending on whether the woman has delivered previously. The pattern in primigravid women (typically diminishing contractility with risk of infection and fistula) may result from tissue acidosis, whereas in parous women, contractility may be maintained with the risk of uterine rupture. Ultimately, tackling the problem of obstructed labour will require universal adequate nutritional intake from childhood and the ability to access adequately equipped and staffed clinical facilities when problems arise in labour. These seem still rather distant aspirations. In the meantime, strategies should be implemented to encourage early recognition of prolonged labour and appropriate clinical responses. The sequelae of obstructed labour can be an enormous source of human misery and the prevention of obstetric fistulas, and skilled treatment if they do occur, are important priorities in regions where obstructed labour is still common.
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Affiliation(s)
- J P Neilson
- Department of Obstetrics & Gynaecology, University of Liverpool, Liverpool, UK.
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36
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Tonelli L, Kramer P, Webster JI, Wray S, Listwak S, Sternberg E. Lipopolysaccharide-induced oestrogen receptor regulation in the paraventricular hypothalamic nucleus of lewis and Fischer rats. J Neuroendocrinol 2002; 14:847-52. [PMID: 12421337 DOI: 10.1046/j.1365-2826.2002.00841.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Oestrogen receptor (ER) regulation of gene transcription in neurosecretory and pituitary cells has been proposed as an important mechanism for increased hypothalamic-pituitary-adrenal (HPA) axis responses in females of several mammalian species, including humans. Inbred female Fischer (F344/N) and Lewis (LEW/N) rats have similar oestrogen levels, although Fischer rats exhibit hyper- and Lewis rats hypo-HPA axis responses. The blunted HPA axis response of Lewis rats has been associated with their blunted hypothalamic corticotropin releasing hormone (CRH) expression. To determine if the female CRH expression deficiency in Lewis rats is associated with defective ER expression and regulation, hypothalamic paraventricular nucleus (PVN) transcript levels of CRH and ER were determined under basal conditions and after immune challenge. Microdissected PVN were obtained from control and lipopolysaccharide (LPS) treated Lewis and Fischer rats and CRH, ERalpha and beta mRNA levels were determined by semiquantitative reverse-transcriptase-polymerase chain reaction. In addition, ERalpha and beta protein levels were determined by semiquantitative Western blots. ERalpha and beta mRNA and protein levels in the PVN of control Fischer rats were significantly higher than in control Lewis rats. ERalpha and beta mRNA and protein levels in Fischer rats were reduced by LPS administration at the time of maximal CRH mRNA levels but did not change in Lewis rats, an effect independent of oestrogen levels. These data indicate that defective neuroendocrine HPA axis responses are associated with defective ER expression and regulation in Lewis PVN despite oestrogen concentrations.
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Affiliation(s)
- L Tonelli
- Section of Neuroendocrine Immunology and Behaviour (SNIB), National Institute of Mental Health, Bethesda, MD 20892, USA.
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37
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Abstract
Macrophage activation and cholesterol processing can be affected by changes in estrogen concentrations. However, there is a paucity of information about the genes and mechanisms regulating this estrogen effect. In primary monocyte-derived macrophages we detected transcript and protein for estrogen receptor beta (ERbeta). Determination of genes regulated by estrogen was completed using cDNA arrays and semiquantitative RT-PCR on RNA isolated from macrophages cultured in serum free media containing (5-10) x 10(-9)M 17-beta-estradiol and subsequently deprived of estrogen for a 24h period. The data indicate that the transcript levels of interleukin 1 receptor antagonist (IL-1ra), beta 2-microglobulin, annexin XI and the LXR(alpha) receptor significantly increased and that Ly-GDI transcript levels significantly decreased after estrogen withdrawal; data congruent with estrogen depletion regulating macrophage inflammatory and biochemical processes. Treatment of THP-1 cells with phorbol 12-myristate-13-acetate in the presence or absence of estrogen indicate that differentiation to a macrophage-like cell type was a prerequisite for production of the estrogen response. In addition, experiments using cycloheximide treatment, that blocks nascent protein synthesis, indicated that estrogen withdrawal affected the transcript levels of LXR(alpha) and IL-1ra through dissimilar pathways.
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Affiliation(s)
- P R Kramer
- Department of Biomedical Sciences, Baylor College of Dentistry, Texas A&M University Health Science Center, 3302 Gaston Avenue, Dallas, TX, USA.
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Abstract
Gonadotropin-releasing hormone (GnRH) neurons, critical for reproduction, are derived from the nasal placode and migrate into the brain along nasal axons. GnRH neurons appear to diverge from olfactory sensory cells during early stages of nasal placode differentiation. However, GnRH neurons rely on olfactory/vomeronasal axons as their pathway to the central nervous system (CNS). A novel factor, termed nasal embryonic luteinizing hormone-releasing hormone factor (NELF), was discovered in a differential screen of migrating versus nonmigrating GnRH neurons. NELF is expressed in olfactory sensory cells and GnRH cells in nasal areas. Antisense experiments demonstrated that knock-down of NELF decreased olfactory axon outgrowth and GnRH neuronal migration. These results indicate that NELF plays a role as a guidance molecule for olfactory axon projections and migration of GnRH cells. We hypothesize that NELF acts via a homophilic interaction and that NELF expression is critical for reproduction by insuring that GnRH cells reach the CNS. Furthermore, down-regulation of NELF on GnRH cells as they enter the telencephalon may allow GnRH cells to distinguish a different pathway(s) in the CNS (from those leading to olfactory regions) and thereby facilitate establishment of the appropriate adult-like GnRH distribution.
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Affiliation(s)
- S Wray
- Cellular and Developmental Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-4156, USA.
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Abstract
Gonadotropin releasing hormone-1 (GnRH-1) neurons, critical for reproduction, are derived from the nasal placode and migrate into the brain during prenatal development. Once within the brain, GnRH-1 cells become integral components of the CNS-pituitary-gonadal axis, essential for reproductive maturation and maintenance of reproductive function in adults. This review focuses on the lineage and development of the GnRH-1 neuroendocrine system. Although the migration of these cells from nose to brain has been well documented in a variety of species, many questions remain concerning the melecules and cues directing GnRH-1 cell differentiation, migration, axon targeting, and establishment and control of GnRH-1 secretion. These process most likely involve multiple and redundant cues because if these mechanisms fail, reproduction dysfunction will ensue and guarantee that this defect does not remain in the gene pool.
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Affiliation(s)
- S Wray
- Cellular and Developmental Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Building 36, Room 5A-21, Bethesda, MD 20892-4156, USA.
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Abstract
OBJECTIVE 1. To assess the contribution of the sarcoplasmic reticulum calcium store in the generation of uterine smooth muscle contractions; 2. to evaluate the contribution of calcium induced calcium release or ryanodine gated calcium channels to myometrial force production. DESIGN Laboratory scientific study. METHODS Myometrial strips were obtained from women undergoing elective prelabour caesarean section at term. These were loaded with the calcium sensitive indicator Indo-1 allowing simultaneous assessment of intracellular calcium concentrations and force production. The effect of exposing the strips to ryanodine (which abolishes calcium induced calcium release), caffeine (which activates calcium induced calcium release) and cyclopiazonic acid (which abolishes the sarcoplasmic reticulum calcium store) was examined. RESULTS Exposure to ryanodine had no appreciable effect on either the amplitude or the duration of the myometrial calcium and force transients but did increase the frequency of contractions (139+/-5%). Caffeine did not potentiate force. Cyclopiazonic acid increased frequency, duration and amplitude of both calcium and force transients. The ability of oxytocin to provoke calcium and force transients in the absence of extracellular calcium was abolished by cyclopiazonic acid but not by ryanodine. CONCLUSIONS These results demonstrate that calcium induced calcium release does not play a significant role in human myometrium and that no functioning role for the ryanodine receptors in human myometrial tissue could be shown. These data suggest that the sarcoplasmic reticulum may act to limit contractions and act as a calcium sink, rather than to amplify contractions.
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Affiliation(s)
- S Kupittayanant
- The Physiological Laboratory, The University of Liverpool, UK
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Kupittayanant S, Burdyga T, Wray S. The effects of inhibiting Rho-associated kinase with Y-27632 on force and intracellular calcium in human myometrium. Pflugers Arch 2001; 443:112-4. [PMID: 11692274 DOI: 10.1007/s004240100668] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2001] [Accepted: 06/11/2001] [Indexed: 11/25/2022]
Abstract
Recent work has indicated that smooth muscle force production may be influenced by pathways not dependent upon the Ca2+-calmodulin phosphorylation of light chains. Few studies, however, have examined the importance of these pathways in intact muscles that contract phasically rather than tonically. Therefore, to determine whether the Ca2+-independent Rho-A and associated kinase (ROK) pathway can affect contractions of the intact human myometrium, we used Y-27632 to inhibit ROK. Three types of contractile activity were examined: spontaneous and those elicited by oxytocin and by depolarisation by high K+. Y-27632 decreased force significantly under all three conditions, without changing intracellular [Ca2+]. However, the effects on force were only large when the uterus was producing force tonically rather than phasically. This suggests that the Rho-A-ROK pathway may not be a potent modulator of force in the human myometrium under physiological conditions.
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Affiliation(s)
- S Kupittayanant
- Department of Physiology, University of Liverpool, Crown Street, Liverpool L69 3BX, UK
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Abstract
Intracellular pH can have profound effects on tissue function, but little is known about how pH is regulated, buffered or affects the function of gastric smooth muscle. As the pH of gastric myocytes may alter with pathophysiological disturbance of the gastric lining, or reduction in blood flow to the stomach, these parameters were investigated. Intracellular pH was measured in strips of corpus from rats and guinea-pigs and pH perturbed by the addition of Na butyrate. pH regulation was investigated using pharmacological inhibitors and ionic substitutions. Resting pH was found to be around 7.0, and buffering power relatively high, compared to other muscles in both species. In the guinea-pig amiloride, EIPA and HOE694 prevented pH regulation from an acid load, but amiloride- and EIPA-insensitive pH-regulating mechanisms were found in the rat. The pH-regulatory mechanism present in the rat was also insensitive to DIDS, SITS and removal of external Cl-, but inhibited by Na+ substitution and HOE694. Acidification reduced gastric tone in both species. We conclude that pH alteration will significantly affect gastric contractility, despite a high capacity of the tissue to buffer and regulate pH change. The sensitivity to NHE inhibitors differs between rat and guinea-pig, suggesting that Na+/H+ exchanger isoform expression differs between gastric tissue.
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Affiliation(s)
- R A Duquette
- Department of Physiology, The University of Liverpool, UK
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43
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Abstract
1. The role of the sarcoplasmic reticulum (SR) was investigated in spontaneous and agonist-induced uterine Ca2+ transients, by combining low- (mag-fluo-4) and high-affinity (fura-2) indicators to measure intraluminal SR ([Ca2+]L) and cytosolic ([Ca2+]i) calcium concentration, simultaneously, in single smooth muscle cells from pregnant rat uterus. 2. Carbachol or ATP, in the absence of extracellular Ca2+, decreased [Ca2+]L and increased [Ca2+]i. Although some replenishment (around 50 %) occurred in its absence, extracellular Ca2+ was required for full replenishment of the SR Ca2+. 3. In 4/15 cells, ATP evoked oscillations of [Ca2+]i. These were accompanied by successive release and re-uptake of SR Ca2+. Inhibition of the SR Ca2+-ATPase with thapsigargin abolished the oscillations and luminal changes. 4. Spontaneous [Ca2+]i transients produced no detectable changes in [Ca2+]L. The larger [Ca2+]i transients evoked by high-K+ depolarisation increased [Ca2+]L. Spontaneous activity was inhibited when [Ca2+]L was increased. 5. These data show that it is possible to simultaneously measure SR and cytosolic [Ca2+], and to investigate their response to agonist application and spontaneous activity.
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Affiliation(s)
- A V Shmigol
- Department of Physiology, University of Liverpool, Crown Street, Liverpool L69 3BX, UK
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44
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Abstract
In this review we discuss our current understanding of the cellular basis of uterine contractility, highlighting those areas requiring further study. It is clear that the basic processes of excitation-contraction coupling lie within the myometrial cell, and that these may be modified by agonists. Pacemaker activity, however, remains a mystery. The contribution of extracellular calcium entry to contraction is shown to be vital, whilst the role of the sarcoplasmic reticulum remains controversial. Much current experimental focus is on pathways controlling and regulating contraction, and we discuss sensitisation mechanisms and question their role in intact uterine preparations. Experimental Physiology (2001) 86.2, 239-246.
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Affiliation(s)
- S Wray
- The Physiological Laboratory, The University of Liverpool, Crown Street, Liverpool L69 3BX, UK
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45
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Abstract
This review concentrates on some of the recent discoveries and future questions relevant to the development of the neuroendocrine luteinizing hormone releasing hormone (LHRH) cells. Neuroendocrine LHRH cells originate outside the central nervous system, in the nasal placode, and thereafter migrate into the forebrain during prenatal development. It is this population of LHRH cells that is responsible for reproductive function, becoming integral members of the hypothalamo-pituitary-gonadal axis postnatally. Disruption of the development of this system results in reproductive dysfunction. Increasing our understanding of LHRH neuroendocrine cells establishes conditions where we can look with greater precision at the mechanisms controlling reproductive development, both activation and failure. In addition, the ability to manipulate the molecular and cellular biology of the LHRH system opens the route to understanding critical neurobiological issues such as phenotypic commitment, axonal path finding and mechanisms involved in neuronal migration. Each of the topics is discussed in turn and potential mechanisms controlling the development of the neuroendocrine LHRH system are indicated.
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Affiliation(s)
- S Wray
- Cellular and Developmental Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-4156, USA.
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46
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Abstract
Evidence indicates that LH-releasing hormone (LHRH) neurons can exhibit neuroendocrine secretory properties before entrance into the central nervous system. In this study, we evaluated LHRH biosynthesis and secretion in embryonic LHRH neurons maintained in nasal explants. Using ELISA and calcium imaging techniques, peptide content and single neuron activities were examined. LHRH neurons maintained for 7-10 days in vitro were found to possess a similar amount of LHRH/cell as the equivalent aged LHRH cells in vivo (postnatal day 1). LHRH peptide was measured in the medium of these relatively young cultures, and 40 mM KCl stimulated a 4-fold increase in LHRH secretion. KCl enhanced medium also resulted in a significant increase in LHRH content per culture (24.5 pg vs. 32.3). A similar effect was observed after muscimol-enhanced media (32.2 pg). Both agents also stimulated a substantial rise in intracellular calcium. Pretreatment of cultures with tetrodotoxin partially blocked the affects of muscimol on both peptide content and calcium activity, but not KCl. Calcium-depleted medium blocked the effects of KCl yet only attenuated the effects of muscimol. Treatment of cultures with cycloheximide blocked the effects of both muscimol and KCl. These results indicate that developing LHRH neurons are capable of synthesizing, secreting, and rapidly replenishing stores of LHRH peptide.
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Affiliation(s)
- J P Moore
- Cellular and Developmental Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA
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Kramer PR, Wray S. Midline nasal tissue influences nestin expression in nasal-placode-derived luteinizing hormone-releasing hormone neurons during development. Dev Biol 2000; 227:343-57. [PMID: 11071759 DOI: 10.1006/dbio.2000.9896] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Neurons differentiating into the luteinizing hormone-releasing hormone (LHRH) neuroendocrine phenotype are derived from the nasal placode. Cells within the vomeronasal organ anlage that turn on LHRH gene and peptide expression subsequently migrate into the forebrain where they influence reproductive function. The molecular and cellular cues regulating differentiation and migration of these cells are unknown. Discovery of developmental markers can indicate proteins directing or associated with differentiation. Analysis of such markers after manipulation of external cues can elucidate important extracellular differentiation signals. Embryonic LHRH neurons were examined in vivo for Mash-1 and nestin, two factors that delineate precursor populations in PNS and forebrain CNS cells. Nestin, but not Mash-1, was detected in early expressing LHRH cells in the vomeronasal organ anlage. These results were duplicated in LHRH neurons maintained in vitro in nasal explants. Such LHRH cells expressed nestin mRNA but not Mash-1 mRNA and were also negative for three other olfactory epithelial developmental transcription factors, Math4A, Math4C/neurogenin1, and NeuroD mRNA. Experimental manipulation of nasal explants revealed dual expression of nestin protein and LHRH in cells proximal to the vomeronasal organ anlage that was dependent upon midline cartilaginous/mesenchymal tissues. Prolonged nestin expression in LHRH cells after midline removal is consistent with nasal midline tissues modulating differentiation of LHRH neurons from the nasal placode.
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Affiliation(s)
- P R Kramer
- Cellular and Developmental Neurobiology Section, National Institutes of Health, Bethesda, Maryland, 20892, USA
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48
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Abstract
This study compared the contractile characteristics of myometrium taken from upper and lower uterine segments. Biopsies were obtained from women undergoing classical caesarean section. Myometrial strips were dissected and mounted in an organ bath, and the contractions were recorded. The cross sectional area of the contractile elements within the strips was measured enabling strips of differing dimensions to be compared. There were no significant differences in the contractile rate and force production produced by myometrium from the upper and lower segments. This study demonstrated that for contractile studies, the use of lower segment is appropriate. The results fail to demonstrate any functional regionality of the human uterus in terms of contractility.
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Affiliation(s)
- M J Luckas
- Department of Obstetrics and Gynaecology, University of Liverpool, Liverpool Women's Hospital, UK
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49
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Kramer PR, Wray S. Novel gene expressed in nasal region influences outgrowth of olfactory axons and migration of luteinizing hormone-releasing hormone (LHRH) neurons. Genes Dev 2000; 14:1824-34. [PMID: 10898796 PMCID: PMC316793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Although a variety of cues have been implicated in axonal targeting during embryogenesis and regeneration, the precise mechanisms guiding olfactory axons remain unclear. Appropriate olfactory axon pathfinding is essential for functional chemoreceptive and pheromone receptive systems. Olfactory axon pathfinding is also necessary for establishment of the neuroendocrine LHRH system, cells critical for reproductive function. LHRH cells exhibit neurophilic migration moving from the nasal region along olfactory axons into the brain. Factors involved in the migration of these neuroendocrine cells are as yet unresolved. We report identification of a novel factor termed nasal embryonic LHRH factor (NELF) that was discovered in a differential screen of migrating versus nonmigrating primary LHRH neurons. NELF is expressed in PNS and CNS tissues during embryonic development, including olfactory sensory cells and LHRH cells. NELF antisense experiments indicate that a reduction in NELF expression decreases olfactory axon outgrowth and the number of LHRH neurons that migrate out of the nasal tissue. These results demonstrate that NELF plays a role as a common guidance molecule for olfactory axon projections and subsequently, either directly or indirectly, in the neurophilic migration of LHRH cells.
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Affiliation(s)
- P R Kramer
- Cellular and Developmental Neurobiology Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, Maryland 20892, USA
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50
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Abstract
In adult rodents, the peptide galanin is expressed in a subpopulation of hypothalamic luteinizing hormone-releasing hormone (LHRH) neurones in an activity-dependent manner. In this investigation, we examined whether galanin mRNA expression in mice was activated coincident with LHRH mRNA expression, as LHRH neurones differentiate from the olfactory placode. Using in situ hybridization, we show (i) that galanin mRNA is coexpressed in LHRH neurones prenatally, (ii) that there is a decrease in galanin mRNA expression relative to LHRH mRNA expression once LHRH mRNA positive/galanin mRNA positive neurones migrate out of the olfactory pit and into the nasal septum, and (iii) the presence of a novel population of galanin mRNA positive/LHRH mRNA negative expressing neurones in the olfactory pit/vomeronasal organ which do not migrate into the central nervous systenm (CNS). This study demonstrates that there are at least two populations of galanin mRNA expressing neurones arising from the olfactory placode; one that remains in nasal regions, is LHRH mRNA negative and whose function is unknown, and one which is coexpressed with LHRH. In addition, the temporal expression of galanin mRNA in LHRH cells indicates that initial activation and subsequent inactivation of galanin mRNA expression is independent of synaptic CNS connections.
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Affiliation(s)
- S Key
- Cellular and Developmental Neurobiology Section, National Institute of Neurological Disease and Stroke, National Institutes of Health, Bethesda, MD 20892-4156, USA
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