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Asunción-Alvarez D, Palacios J, Ybañez-Julca RO, Rodriguez-Silva CN, Nwokocha C, Cifuentes F, Greensmith DJ. Calcium signaling in endothelial and vascular smooth muscle cells: sex differences and the influence of estrogens and androgens. Am J Physiol Heart Circ Physiol 2024; 326:H950-H970. [PMID: 38334967 DOI: 10.1152/ajpheart.00600.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 02/05/2024] [Accepted: 02/05/2024] [Indexed: 02/10/2024]
Abstract
Calcium signaling in vascular endothelial cells (ECs) and smooth muscle cells (VSMCs) is essential for the regulation of vascular tone. However, the changes to intracellular Ca2+ concentrations are often influenced by sex differences. Furthermore, a large body of evidence shows that sex hormone imbalance leads to dysregulation of Ca2+ signaling and this is a key factor in the pathogenesis of cardiovascular diseases. In this review, the effects of estrogens and androgens on vascular calcium-handling proteins are discussed, with emphasis on the associated genomic or nongenomic molecular mechanisms. The experimental models from which data were collected were also considered. The review highlights 1) in female ECs, transient receptor potential vanilloid 4 (TRPV4) and mitochondrial Ca2+ uniporter (MCU) enhance Ca2+-dependent nitric oxide (NO) generation. In males, only transient receptor potential canonical 3 (TRPC3) plays a fundamental role in this effect. 2) Female VSMCs have lower cytosolic Ca2+ levels than males due to differences in the activity and expression of stromal interaction molecule 1 (STIM1), calcium release-activated calcium modulator 1 (Orai1), calcium voltage-gated channel subunit-α1C (CaV1.2), Na+-K+-2Cl- symporter (NKCC1), and the Na+/K+-ATPase. 3) When compared with androgens, the influence of estrogens on Ca2+ homeostasis, vascular tone, and incidence of vascular disease is better documented. 4) Many studies use supraphysiological concentrations of sex hormones, which may limit the physiological relevance of outcomes. 5) Sex-dependent differences in Ca2+ signaling mean both sexes ought to be included in experimental design.
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Affiliation(s)
- Daniel Asunción-Alvarez
- Laboratorio de Bioquímica Aplicada, Química y Farmacia, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique, Chile
| | - Javier Palacios
- Laboratorio de Bioquímica Aplicada, Química y Farmacia, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique, Chile
| | - Roberto O Ybañez-Julca
- Departamento de Farmacología, Facultad de Farmacia y Bioquímica, Universidad Nacional de Trujillo, Trujillo, Perú
| | - Cristhian N Rodriguez-Silva
- Departamento de Farmacología, Facultad de Farmacia y Bioquímica, Universidad Nacional de Trujillo, Trujillo, Perú
| | - Chukwuemeka Nwokocha
- Department of Basic Medical Sciences Physiology Section, Faculty of Medical Sciences, The University of the West Indies, Kingston, Jamaica
| | - Fredi Cifuentes
- Laboratorio de Fisiología Experimental (EphyL), Instituto Antofagasta (IA), Universidad de Antofagasta, Antofagasta, Chile
| | - David J Greensmith
- Biomedical Research Centre, School of Science, Engineering and Environment, The University of Salford, Salford, United Kingdom
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Subbamanda YD, Bhargava A. Intercommunication between Voltage-Gated Calcium Channels and Estrogen Receptor/Estrogen Signaling: Insights into Physiological and Pathological Conditions. Cells 2022; 11:cells11233850. [PMID: 36497108 PMCID: PMC9739980 DOI: 10.3390/cells11233850] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 11/25/2022] [Accepted: 11/28/2022] [Indexed: 12/05/2022] Open
Abstract
Voltage-gated calcium channels (VGCCs) and estrogen receptors are important cellular proteins that have been shown to interact with each other across varied cells and tissues. Estrogen hormone, the ligand for estrogen receptors, can also exert its effects independent of estrogen receptors that collectively constitute non-genomic mechanisms. Here, we provide insights into the VGCC regulation by estrogen and the possible mechanisms involved therein across several cell types. Notably, most of the interaction is described in neuronal and cardiovascular tissues given the importance of VGCCs in these electrically excitable tissues. We describe the modulation of various VGCCs by estrogen known so far in physiological conditions and pathological conditions. We observed that in most in vitro studies higher concentrations of estrogen were used while a handful of in vivo studies used meager concentrations resulting in inhibition or upregulation of VGCCs, respectively. There is a need for more relevant physiological assays to study the regulation of VGCCs by estrogen. Additionally, other interacting receptors and partners need to be identified that may be involved in exerting estrogen receptor-independent effects of estrogen.
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Peixoto P, Vieira-Alves I, Couto GK, Lemos VS, Rossoni LV, Bissoli NS, Dos Santos RL. Sex differences in the participation of endothelial mediators and signaling pathways involved in the vasodilator effect of a selective GPER agonist in resistance arteries of gonadectomized Wistar rats. Life Sci 2022; 308:120917. [PMID: 36044974 DOI: 10.1016/j.lfs.2022.120917] [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: 07/10/2022] [Revised: 08/16/2022] [Accepted: 08/24/2022] [Indexed: 11/15/2022]
Abstract
AIM Endothelial mechanisms underlying the vascular effects of estrogen modulated by the G protein-coupled estrogen receptor (GPER) are not well understood, especially in gonadal sex hormone deprivation. Thus, we investigated vascular function and endothelial signaling pathways involved in the selective activation of GPER in resistance arteries of gonadectomized rats. METHODS Gonadectomy was performed in Wistar rats of both sexes. After 21 days, the animals were euthanized. Concentration-response curves were obtained by cumulative additions of G-1 in third-order mesenteric arteries. The vasodilatory effects of G-1 were evaluated before and after endothelium removal or incubation with pharmacological inhibitors. Tissue protein expression was measured by western blotting. Assays with 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate (DAF-FM) and 2',7' dichlorodihydrofluorescein-diacetate (DCF-DA) were performed in the arteries investigated. Immunolocalization was assessed by immunofluorescence. RESULTS G-1 induced partially endothelium-dependent relaxation in both sexes. The three isoforms of the enzyme nitric oxide synthase contributed to the production and release of nitric oxide in both gonadectomized groups, but the role of inducible nitric oxide synthase is more expressive in males. The mechanistic pathway by which endothelial nitric oxide synthase is phosphorylated appears to differ between sexes, with the rapid signaling pathway phosphatidylinositol-3-kinase/protein kinase B/endothelial nitric oxide synthase (PI3k-Akt-eNOS) being identified for males and mitogen-activated protein kinase/extracellular signal-regulated kinase/endothelial nitric oxide synthase (MEK-ERK-eNOS) for females. The contribution of hydrogen peroxide as an endothelial relaxation mediator seems to be greater in females. CONCLUSION These results provide new insights into the effects of estrogen-induced responses via GPER on vascular function in gonadal sex hormone deprivation.
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Affiliation(s)
- Pollyana Peixoto
- Department of Physiological Sciences, Universidade Federal do Espírito Santo, Vitoria, ES, Brazil
| | - Ildernandes Vieira-Alves
- Department of Physiology and Biophysics, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Gisele Kruger Couto
- Department of Physiology and Biophysics, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Virgínia Soares Lemos
- Department of Physiology and Biophysics, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | | | - Nazaré Souza Bissoli
- Department of Physiological Sciences, Universidade Federal do Espírito Santo, Vitoria, ES, Brazil
| | - Roger Lyrio Dos Santos
- Department of Physiological Sciences, Universidade Federal do Espírito Santo, Vitoria, ES, Brazil.
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Estradiol and Estrogen-like Alternative Therapies in Use: The Importance of the Selective and Non-Classical Actions. Biomedicines 2022; 10:biomedicines10040861. [PMID: 35453610 PMCID: PMC9029610 DOI: 10.3390/biomedicines10040861] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 04/03/2022] [Accepted: 04/04/2022] [Indexed: 12/17/2022] Open
Abstract
Estrogen is one of the most important female sex hormones, and is indispensable for reproduction. However, its role is much wider. Among others, due to its neuroprotective effects, estrogen protects the brain against dementia and complications of traumatic injury. Previously, it was used mainly as a therapeutic option for influencing the menstrual cycle and treating menopausal symptoms. Unfortunately, hormone replacement therapy might be associated with detrimental side effects, such as increased risk of stroke and breast cancer, raising concerns about its safety. Thus, tissue-selective and non-classical estrogen analogues have become the focus of interest. Here, we review the current knowledge about estrogen effects in a broader sense, and the possibility of using selective estrogen-receptor modulators (SERMs), selective estrogen-receptor downregulators (SERDs), phytoestrogens, and activators of non-genomic estrogen-like signaling (ANGELS) molecules as treatment.
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5
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Lorigo M, Mariana M, Lemos MC, Cairrao E. Vascular mechanisms of testosterone: The non-genomic point of view. J Steroid Biochem Mol Biol 2020; 196:105496. [PMID: 31655180 DOI: 10.1016/j.jsbmb.2019.105496] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 09/26/2019] [Accepted: 10/07/2019] [Indexed: 01/19/2023]
Abstract
Testosterone (T) is the predominant endogenous androgen in the bloodstream. At the vascular level, T presents genomic and non-genomic effects, and both effects may overlap. The genomic actions assume that androgens can freely cross the plasma membrane of target cells and bind to nuclear androgen receptors, inducing gene transcription and protein synthesis. The non-genomic effects have a more rapid onset and may be related to the interaction with protein/receptor/ion channels of the plasma membrane. The key T effect at the vascular level is vasorelaxation, which is primarily due to its rapid effect. Thus, the main purpose of this review is to discuss the T non-genomic effects at the vascular level and the molecular pathways involved in its vasodilator effect observed in in vivo and in vitro studies. In this sense, the nuclear receptor activation, the influence of vascular endothelium and the activation or inhibition of ion channels (potassium and calcium channels, respectively) will be reviewed regarding all the data that corroborated or not. Moreover, this review also provides a brief update on the association of T with the risk factors for cardiovascular diseases, namely metabolic syndrome, type 2 diabetes mellitus, obesity, atherosclerosis, dyslipidaemia, and hypertension. In summary, in this paper we consider the non-genomic vascular mode of action of androgen in physiological conditions and the main risk factors for cardiovascular diseases.
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Affiliation(s)
- Margarida Lorigo
- CICS-UBI - Centro de Investigação em Ciências da Saúde, University of Beira Interior, 6200-506 Covilhã, Portugal.
| | - Melissa Mariana
- CICS-UBI - Centro de Investigação em Ciências da Saúde, University of Beira Interior, 6200-506 Covilhã, Portugal.
| | - Manuel C Lemos
- CICS-UBI - Centro de Investigação em Ciências da Saúde, University of Beira Interior, 6200-506 Covilhã, Portugal.
| | - Elisa Cairrao
- CICS-UBI - Centro de Investigação em Ciências da Saúde, University of Beira Interior, 6200-506 Covilhã, Portugal.
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Udry M, Kardon RH, Sadun F, Kawasaki A. The Tadpole Pupil: Case Series With Review of the Literature and New Considerations. Front Neurol 2019; 10:846. [PMID: 31481920 PMCID: PMC6709659 DOI: 10.3389/fneur.2019.00846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 07/22/2019] [Indexed: 11/25/2022] Open
Abstract
Tadpole pupil is a rare phenomenon in which segmental spasm of the iris dilator muscle results in a tadpole-shaped pupil. The pupillary distortion is usually unilateral, lasts several minutes, and can recur in clusters. Any segment of the iris can be affected; thus, for some patients, a different-shaped tadpole pupil is noticed from episode to episode. Tadpole pupil most commonly appears spontaneously in young women. Tadpole pupil is not associated with any systemic disorders, but an ipsilateral Horner syndrome is noted in 46% of patients. In this article, we have reviewed the existing literature of tadpole pupil, compiling all the published cases in a table and reporting four additional cases to re-examine the clinical profile of this disorder and to consider the different purported mechanisms as means to understand its possible etiology and treatment. The common denominator in the pathophysiology of tadpole pupil is a focal excessive contraction (segmental spasm) of the iris dilator muscle. Based on various proposed pathophysiologic mechanism of tadpole pupil, we can consider potential forms of treatment.
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Affiliation(s)
- Morgane Udry
- FondationAsile des Aveugles, Department of Biology and Medicine, Hôpital Ophtalmique Jules Gonin, University of Lausanne, Lausanne, Switzerland
| | - Randy H. Kardon
- Department of Ophthalmology and Visual Sciences, Iowa City VA Center of Excellence for the Prevention and Treatment of Vision Loss, University of Iowa and Veterans Affairs Hospital, Iowa City, IA, United States
| | | | - Aki Kawasaki
- FondationAsile des Aveugles, Department of Biology and Medicine, Hôpital Ophtalmique Jules Gonin, University of Lausanne, Lausanne, Switzerland
- *Correspondence: Aki Kawasaki
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Filgueira FP, Lobato NS, Nascimento DL, Ceravolo GS, Giachini FRC, Lima VV, Dantas AP, Fortes ZB, Webb RC, Tostes RC, Carvalho MHC. Equilin displays similar endothelium-independent vasodilator potential to 17β-estradiol regardless of lower potential to inhibit calcium entry. Steroids 2019; 141:46-54. [PMID: 30458188 PMCID: PMC6984400 DOI: 10.1016/j.steroids.2018.11.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 10/21/2018] [Accepted: 11/14/2018] [Indexed: 12/24/2022]
Abstract
Conjugated equine estrogens (CEE) have been widely used by women who seek to relieve symptoms of menopause. Despite evidence describing protective effects against risk factors for cardiovascular diseases by naturally occurring estrogens, little is known about the vascular effects of equilin, one of the main components of CEE and not physiologically present in women. In this regard, the present study aims to compare the vascular effects of equilin in an experimental model of hypertension with those induced by 17β-estradiol. Resistance mesenteric arteries from female spontaneously hypertensive rats (SHR) were used for recording isometric tension in a small vessel myograph. As effectively as 17β-estradiol, equilin evoked a concentration-dependent relaxation in mesenteric arteries from female SHRs contracted with KCl, U46619, PDBu or ET-1. Equilin-induced vasodilation does not involve classical estrogen receptor activation, since the estrogen receptor antagonist (ICI 182,780) failed to inhibit relaxation in U46619-precontracted mesenteric arteries. Vasorelaxation was not affected by either endothelium removal or by inhibiting the release or action of endothelium-derived factors. Incubation with L-NAME (NOS inhibitor), ODQ (guanylyl cyclase inhibitor) or KT5823 (inhibitor of protein kinase G) did not affect equilin-induced relaxation. Similarly, indomethacin (COX inhibitor) or blockage of potassium channels with tetraethylammonium, glibenclamide, 4-aminopyridine, or ouabain did not affect equilin-induced relaxation. Inhibitors of adenylyl cyclase SQ22536 or protein kinase A (KT5720) also had no effects on equilin-induced relaxation. While 17β-estradiol inhibited calcium (Ca2+) -induced contractions in high-K+ depolarization medium in a concentration-dependent manner, equilin induced a slight rightward-shift in the contractile responses to Ca2+. Comparable pattern of responses were observed in the concentration-response curves to (S)-(-)-Bay K 8644, a L-type Ca2+ channel activator. Equilin was unable to block the transitory contraction produced by caffeine-induced Ca2+ release from intracellular stores. In conclusion, equilin blocks L-type Ca2+ channels less effectively than 17β-estradiol. Despite its lower effectiveness, equilin equally relaxes resistance mesenteric arteries by blocking Ca2+ entry on smooth muscle.
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Affiliation(s)
- Fernando P Filgueira
- Department of Pharmacology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil; Department of Physiology, Augusta University, Augusta, GA, USA; Faculty of Medicine, Institute of Health Sciences, Federal University of Jatai, Jatai, GO, Brazil.
| | - Núbia S Lobato
- Department of Pharmacology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil; Department of Physiology, Augusta University, Augusta, GA, USA; Faculty of Medicine, Institute of Health Sciences, Federal University of Jatai, Jatai, GO, Brazil
| | - Denise L Nascimento
- Faculty of Medicine, Institute of Health Sciences, Federal University of Jatai, Jatai, GO, Brazil
| | - Graziela S Ceravolo
- Department of Pharmacology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil; Department of Physiological Sciences, Biological Sciences Center, State University of Londrina, Londrina, PR, Brazil
| | - Fernanda R C Giachini
- Department of Physiology, Augusta University, Augusta, GA, USA; Institute of Biological and Health Sciences, Federal University of Mato Grosso, Barra do Garças, MT, Brazil
| | - Victor V Lima
- Department of Physiology, Augusta University, Augusta, GA, USA; Institute of Biological and Health Sciences, Federal University of Mato Grosso, Barra do Garças, MT, Brazil; Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Ana Paula Dantas
- Experimental Cardiology, Institut Clínic Cardiovascular, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
| | - Zuleica B Fortes
- Department of Pharmacology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - R Clinton Webb
- Department of Physiology, Augusta University, Augusta, GA, USA
| | - Rita C Tostes
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Maria Helena C Carvalho
- Department of Pharmacology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil
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Hill BJF, Dalton RJ, Joseph BK, Thakali KM, Rusch NJ. 17β-estradiol reduces Ca v 1.2 channel abundance and attenuates Ca 2+ -dependent contractions in coronary arteries. Pharmacol Res Perspect 2018; 5. [PMID: 28971605 PMCID: PMC5625162 DOI: 10.1002/prp2.358] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 07/05/2017] [Accepted: 08/04/2017] [Indexed: 12/21/2022] Open
Abstract
One mechanism by which the female sex may protect against elevated coronary vascular tone is inhibition of Ca2+ entry into arterial smooth muscle cells (ASMCs). In vitro findings confirm that high estrogen concentrations directly inhibit voltage‐dependent Cav1.2 channels in coronary ASMCs. For this study, we hypothesized that the nonacute, in vitro exposure of coronary arteries to a low concentration of 17β‐estradiol (17βE) reduces the expression of Cav1.2 channel proteins in coronary ASMCs. Segments of the right coronary artery obtained from sexually mature female pigs were mounted for isometric tension recording. As expected, our results indicate that high concentrations (≥10 μmol/L) of 17βE acutely attenuated Ca2+‐dependent contractions to depolarizing KCl stimuli. Interestingly, culturing coronary arteries for 24 h in a 10,000‐fold lower concentration (1 nmol/L) of 17βE also attenuated KCl‐induced contractions and reduced the contractile response to the Cav1.2 agonist, FPL64176, by 50%. Western blots revealed that 1 nmol/L 17βE decreased protein expression of the pore‐forming α1C subunit (Cavα) of the Cav1.2 channel by 35%; this response did not depend on an intact endothelium. The 17βE‐induced loss of Cavα protein in coronary arteries was prevented by the estrogen ERα/ERβ antagonist, ICI 182,780, whereas the GPER antagonist, G15, did not prevent it. There was no effect of 1 nmol/L 17βE on Cavα transcript expression. We conclude that 17βE reduces Cav1.2 channel abundance in isolated coronary arteries by a posttranscriptional process. This unrecognized effect of estrogen may confer physiological protection against the development of abnormal Ca2+‐dependent coronary vascular tone.
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Affiliation(s)
- Brent J F Hill
- Department of Biology, University of Central Arkansas Conway, Conway, Arkansas
| | - Robin J Dalton
- Department of Biology, University of Central Arkansas Conway, Conway, Arkansas
| | - Biny K Joseph
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Keshari M Thakali
- Arkansas Children's Nutrition Center & Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Nancy J Rusch
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas
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Baumgartner C, Hubacher T, Krayer M, Gschossmann J. In vitro spontaneous contractile activity of colonic smooth muscle in naive Lewis rats: Acute effect of gonadal hormones. J Dig Dis 2017; 18:13-22. [PMID: 28009091 DOI: 10.1111/1751-2980.12438] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 12/07/2016] [Accepted: 12/15/2016] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Functional gastrointestinal disorders affect females more often. Changes in colonic motility may be etiological co-factors for the clinical symptoms. The aim of the present study was to analyze the influence of gonadal hormones on colonic contractile activity. METHODS In vitro measurements of colonic contractile activity in longitudinal smooth muscle strips of female and male Lewis rats were performed in an organ chamber experiment. After the administration of a gonadal hormone estradiol [EST], progesterone [PROG] and testosterone [TEST]) or ethanol solution as control, stimulation with acetylcholine (ACh) or inhibition with norepinephrine (NE) was performed. RESULTS Compared to the smooth muscle strips of male rats, significantly higher spontaneous colonic contractile activity (SCCA) was observed in female animals. Increasing doses of ACh showed the progressive stimulation of SCCA whereas rising doses of NE resulted in a stepwise inhibition of SCCA, respectively. EST superfusion displayed an inhibitory effect on SCCA in both sexes and inhibited the ACh effect in female rats. Similarly, acute superfusion with high-dose PROG inhibited SCCA in females. Acute TEST superfusion inhibited SCCA in males and led to significant higher colonic contractile activity in males following subsequent stimulation with ACh. In female rats, the inhibitory effect of NE was reduced by prior exposure to TEST. CONCLUSION In our in vitro study the acute exposure of colonic smooth muscle tissue to gonadal hormones led to sex-dependent changes in SCCA and translated in a modified response of smooth muscle strips to both pro-contractile and anti-contractile neurotransmitters.
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Affiliation(s)
- Christine Baumgartner
- Department of Visceral Surgery and Medicine, University Hospital of Berne, Bern, Switzerland.,Department of Clinical Research, University Hospital of Berne, Bern, Switzerland
| | - Thomas Hubacher
- Department of Visceral Surgery and Medicine, University Hospital of Berne, Bern, Switzerland.,Department of Clinical Research, University Hospital of Berne, Bern, Switzerland
| | - Magali Krayer
- Department of Visceral Surgery and Medicine, University Hospital of Berne, Bern, Switzerland.,Department of Clinical Research, University Hospital of Berne, Bern, Switzerland
| | - Juergen Gschossmann
- Department of Visceral Surgery and Medicine, University Hospital of Berne, Bern, Switzerland.,Department of Clinical Research, University Hospital of Berne, Bern, Switzerland.,Department of Internal Medicine, Forchheim Clinic, Forchheim, Germany
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10
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Kline L, Karpinski E. Gallbladder motility and the sex of the guinea pig. Physiol Rep 2016; 4:4/12/e12843. [PMID: 27354545 PMCID: PMC4923241 DOI: 10.14814/phy2.12843] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 06/03/2016] [Indexed: 11/24/2022] Open
Abstract
Progesterone (P), 17β‐estradiol (E2), and dihydrotestosterone (DHT) affect gallbladder motility. When gallbladders were taken from women and men, women had more estrogen and P receptors than men. Both P and E2 had an inhibitory effect upon gallbladder contractility in men and premenopausal and postmenopausal women. Similar findings have been reported in gallbladder strips from male and female guinea pigs. In the present study, there was no significant difference in the amount of E2‐, P‐, or DHT‐induced relaxation of CCK‐induced tension when the responses in gallbladder strips from male and female guinea pigs were compared. Three metabolites of P were used: 17‐hydroxyprogesterone (17‐P), 20α‐hydroxyprogesterone (20‐P), and 21‐hydroxyprogesterone (21‐P). There was no significant difference in the responses from strips from male and female guinea pigs. In order to determine if the effects of E2 and P were additive, strips from male animals were exposed to either E2 or P and the amount of relaxation recorded. After recovery, the strips were exposed to E2 or P in reverse order to ensure the order of treatment had no effect. Then, the strips were treated with both E2 and P simultaneously and the relaxation recorded. This procedure was repeated with strips from female guinea pigs. The effect of E2 and P was found to be additive; however, the response of the strips from each sex were not significantly different. It is concluded that the sex of the guinea pig has no significant effect on the response to the sex hormones used.
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Affiliation(s)
- Loren Kline
- University of Alberta, School of Dentistry, Edmonton, Alberta, Canada
| | - Edward Karpinski
- Department of Physiology, University of Alberta, Edmonton, Canada
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11
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Lee MC, Yang YC, Chen YC, Chang BS, Li YC, Huang SC. Estrogen and G protein-coupled estrogen receptor agonist G-1 cause relaxation of human gallbladder. Tzu Chi Med J 2016; 28:54-58. [PMID: 28757722 PMCID: PMC5442889 DOI: 10.1016/j.tcmj.2016.03.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 02/29/2016] [Accepted: 03/25/2016] [Indexed: 11/02/2022] Open
Abstract
OBJECTIVE Estrogen interacts with a membrane receptor, G protein-coupled estrogen receptor (GPER). It was reported that 17β-estradiol was able to inhibit contraction of the human colon and cause relaxation of the guinea pig gallbladder, however, the involvement of GPER was not clarified. The aim of the present study was to investigate the effect of estrogen on human gallbladder motility and the possible role of GPER. MATERIALS AND METHODS Relaxation of human gallbladder strips were measured using isometric transducers. Expression of GPER was evaluated by reverse transcription polymerase chain reaction (PCR), realtime PCR, and immunohistochemistry. RESULTS In human gallbladder strips, 17β-estradiol and G-1 elicited marked and rapid relaxation, whereas tamoxifen produced mild concentration-dependent relaxation. The relative efficacies to cause relaxation were as follows: 17β-estradiol = G-1 > tamoxifen. The relaxant response of 17β-estradiol was not attenuated by tetrodotoxin or conotoxin GVIA. This implies that nerve stimulation was not involved in the 17β-estradiol-induced gallbladder relaxation. Analysis by reverse transcription PCR and real-time PCR showed that GPER was expressed in the human gallbladder. Further analysis by immunohisto-chemistry revealed that GPER was expressed in the gallbladder muscle. This suggests that 17β-estradiol relaxes the human gallbladder via GPER. CONCLUSION These results demonstrate for the first time that 17β-estradiol and GPER agonist G-1 cause relaxation of the human gallbladder, probably through GPER. Estrogen might play an important role in the control of human gallbladder motility.
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Affiliation(s)
- Ming-Che Lee
- Department of Surgery, Buddhist Tzu Chi General Hospital, Hualien, Taiwan.,Department of Surgery, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Ying-Chin Yang
- Department of Surgery, Buddhist Tzu Chi General Hospital, Hualien, Taiwan.,Department of Surgery, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Yen-Cheng Chen
- Department of Surgery, Buddhist Tzu Chi General Hospital, Hualien, Taiwan.,Department of Surgery, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Bee-Song Chang
- Department of Surgery, Buddhist Tzu Chi General Hospital, Hualien, Taiwan.,Department of Surgery, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Yi-Chen Li
- Department of Medical Research, E-Da Hospital, Kaohsiung, Taiwan
| | - Shih-Che Huang
- Department of Internal Medicine, Toyotomicho National Health Insurance Hospital, Toyotomi, Hokkaido, Japan.,Department of Internal Medicine, E-Da Hospital, Kaohsiung, Taiwan
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Jodati AR, Babaei H, Azarmi Y, Fallah S, Gharebageri A, Fouladi DF, Safaei N. Vasorelaxant effect of 17α-ethynylestradiol on human saphenous vein. Adv Pharm Bull 2015; 5:89-96. [PMID: 25789224 DOI: 10.5681/apb.2015.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Revised: 05/25/2014] [Accepted: 05/26/2014] [Indexed: 11/17/2022] Open
Abstract
PURPOSE A protective effect for estrogens against cardiovascular problems has long been known. The aim of this study was to investigate the vasorelaxant effect of 17α-Ethynylestradiol (17α-EE) on human saphenous vein. METHODS The veins were suspended horizontally between two triangular stainless steel hooks for the measurement of isometric tension in individual organ baths containing 10ml Krebs solution, at 37°C and gassed with carbogen under 3gr optimum tension. The effect of different concentrations of 17α-EE (2-40 μM) on vascular tone was investigated in veins precontracted with PGF2α. Relaxation was measured after 40min and expressed as the percent decrease of initial contraction. To determine the involvement of potassium channels, endothelium, nitric oxide synthase, guanylylcyclase and prostaglandins in the vasorelaxant effect of estrogen, the veins were incubated with tetraethyl ammonium, N-nitro-L-arginine methyl ester, methylene blue or indomethacin, respectively for 20min prior to experimentation. Responses to 17α-EE were directly compared to those obtained in the same tissues in the absence of the inhibitors. RESULTS The mean relaxations induced by 17α-EE with concentrations of 2, 5, 10, 20 and 40μM in tissues precontracted with PGF2α were 19.8 ±5.5%, 26.1±10.8%, 32.2±7.4%, 48.6±10.8%and56±7.6%, respectively. The results of the inhibition of potassium channels, nitric oxide synthase, guanylylcyclase, cyclooxygenase and removing endothelium in relaxation induced by 17α-EE on precontracted veins with PGF2α proved no significant differences. CONCLUSION This study showed that 17α-EE has significant vasorelaxant effect on human saphenous vein in a concentration-dependent manner. This effect is probably independent of potassium channels, nitric oxide synthase, guanylylcyclase, prostaglandin synthesis and endothelium functions.
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Affiliation(s)
- Ahmad Reza Jodati
- Cardiovascular Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Hossein Babaei
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran. ; School of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Yadollah Azarmi
- School of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Sahar Fallah
- School of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Afsaneh Gharebageri
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Naser Safaei
- Cardiovascular Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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Abstract
OBJECTIVE Sex hormone status has been demonstrated to play a role in the regulation of ion channel activity. We previously demonstrated increased L-type Ca channel current (ICa) in the coronary smooth muscle cells (SMCs) of male swine compared with female swine. In male swine, endogenous testosterone increases ICa in SMCs by enhanced expression of the pore-forming α1 subunit Cav1.2. Conversely, the role of sex hormones in female swine has not previously been investigated. Therefore, the purpose of the current study was to determine the effect of ovariectomy (OVX) on L-type Ca channel activity and expression in female Yucatan miniature swine. METHODS Sexually mature female swine were obtained from a breeder and either left intact (intact female [IF]; n = 5) or ovariectomized (n = 6). RESULTS Sensitivity to depolarization-induced contractions was increased by OVX. Accordingly, mean (SEM) ICa was enhanced in the OVX group (-9.5 [0.6] pA/pF) compared with the IF group (-4.5 [0.3] pA/pF), although L-type Ca channel α1 subunit (Cav1.2; α1c) messenger RNA (mRNA) and protein expressions were unchanged.Among the L-type Ca channel β subunits, β1 (188 [31]) and β2a (561 [79]) had higher mRNA expression levels (target/18S) than β3 (9 [1]) and β4 (2 [0.1]). Although β2a, β3, and β4 mRNA and protein expressions were not different between groups, protein expression of the β1 subunit (Cavβ1) was decreased in the OVX group compared with the IF group. CONCLUSIONS Endogenous female hormones inhibit L-type Ca channel activity in coronary SMCs potentially via the up-regulation of Cavβ1 subunit expression.
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Hill BJF, Muldrew E. Oestrogen upregulates the sarcoplasmic reticulum Ca(2+) ATPase pump in coronary arteries. Clin Exp Pharmacol Physiol 2015; 41:430-6. [PMID: 24684418 DOI: 10.1111/1440-1681.12233] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 03/20/2014] [Accepted: 03/25/2014] [Indexed: 12/30/2022]
Abstract
The presence of circulating plasma 17β-oestradiol (E2) is beneficial in women against abnormal vascular tone development, such as coronary arterial vasospasms. Several vascular diseases have demonstrated that increased expression of the sarcoplasmic reticulum Ca(2+) -ATPase pump (SERCA2b) serves to limit the excessive accumulation of intracellular Ca(2+) . Therefore, the hypothesis of the present study was that E2 would increase SERCA2b expression in the coronary vasculature. Coronary arteries were dissected from hearts obtained from mature female pigs. Artery segments were cultured for 24 h in E2 (1 pmol/L or 1 nmol/L) and homogenized for western blot analysis. At 1 nmol/L, E2 induced an approximate 50% increase in immunoreactivity for SERCA2b. In addition, E2 increased the protein expression of the known SERCA regulatory proteins, protein kinase A (PKA) and protein kinase G (PKG). The E2-induced increase in SERCA2b was attenuated when the culture medium was supplemented with the oestrogen receptor (ER) α/β antagonist ICI 182,780 and the PKG antagonist KT5823 (10 μmol/L, 24 h for both). The PKA antagonist (KT5720; 10 μmol/L, 24 h) had no effect on SERCA2b expression. Removal of the endothelium (using a wooden toothpick) from artery segments prior to culture decreased the E2-mediated increase in SERCA2b and PKG expression by 45% and 47%, respectively. Overall, the findings suggest that one of the potential cardiovascular benefits of E2 in women is upregulation of SERCA2b, via activation of the classic ERα and ERβ pathway.
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Affiliation(s)
- Brent J F Hill
- Department of Biology, University of Central Arkansas, Conway, AR, USA
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15
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Ramírez-Rosas MB, Cobos-Puc LE, Sánchez-López A, Gutiérrez-Lara EJ, Centurión D. Pharmacological characterization of the mechanisms involved in the vasorelaxation induced by progesterone and 17β-estradiol on isolated canine basilar and internal carotid arteries. Steroids 2014; 89:33-40. [PMID: 25072792 DOI: 10.1016/j.steroids.2014.07.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 07/01/2014] [Accepted: 07/17/2014] [Indexed: 12/29/2022]
Abstract
Progesterone and 17β-estradiol induce vasorelaxation through non-genomic mechanisms in several isolated blood vessels; however, no study has systematically evaluated the mechanisms involved in the relaxation induced by 17β-estradiol and progesterone in the canine basilar and internal carotid arteries that play a key role in cerebral circulation. Thus, relaxant effects of progesterone and 17β-estradiol on KCl- and/or PGF2α-pre-contracted arterial rings were investigated in absence or presence of several antagonists/inhibitors/blockers; the effect on the contractile responses to CaCl2 was also determined. In both arteries progesterone (5.6-180 μM) and 17β-estradiol (1.8-180 μM): (1) produced concentration-dependent relaxations of KCl- or PGF2α-pre-contracted arterial rings; (2) the relaxations were unaffected by actinomycin D (10 μM), cycloheximide (10 μM), SQ 22,536 (100 μM) or ODQ (30 μM), potassium channel blockers and ICI 182,780 (only for 17β-estradiol). In the basilar artery the vasorelaxation induced by 17β-estradiol was slightly blocked by tetraethylammonium (10mM) and glibenclamide (KATP; 10 μM). In both arteries, progesterone (10-100 μM), 17β-estradiol (3.1-31 μM) and nifedipine (0.01-1 μM) produced a concentration-dependent blockade of the contraction to CaCl2 (10 μM-10mM). These results suggest that progesterone and 17β-estradiol produced relaxation in the basilar and internal carotid arteries by blockade of L-type voltage dependent Ca(2+) channel but not by genomic mechanisms or production of cAMP/cGMP. Potassium channels did not play a role in the relaxation to progesterone in both arteries or in the effect of 17β-estradiol in the internal carotid artery; meanwhile KATP channels play a minor role on the effect of 17β-estradiol in the basilar artery.
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Affiliation(s)
- Martha B Ramírez-Rosas
- Departamento de Farmacobiología, Cinvestav-Coapa, Czda. de los Tenorios 235, Col. Granjas-Coapa, Deleg. Tlalpan, C.P. 14330, México D.F., Mexico
| | - Luis E Cobos-Puc
- Departamento de Farmacobiología, Cinvestav-Coapa, Czda. de los Tenorios 235, Col. Granjas-Coapa, Deleg. Tlalpan, C.P. 14330, México D.F., Mexico
| | - Araceli Sánchez-López
- Departamento de Farmacobiología, Cinvestav-Coapa, Czda. de los Tenorios 235, Col. Granjas-Coapa, Deleg. Tlalpan, C.P. 14330, México D.F., Mexico
| | - Erika J Gutiérrez-Lara
- Departamento de Farmacobiología, Cinvestav-Coapa, Czda. de los Tenorios 235, Col. Granjas-Coapa, Deleg. Tlalpan, C.P. 14330, México D.F., Mexico
| | - David Centurión
- Departamento de Farmacobiología, Cinvestav-Coapa, Czda. de los Tenorios 235, Col. Granjas-Coapa, Deleg. Tlalpan, C.P. 14330, México D.F., Mexico.
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Kline LW, Karpinski E. The flavonoid chrysin, an endocrine disrupter, relaxes cholecystokinin- and KCl-induced tension in male guinea pig gallbladder strips through multiple signaling pathways. Steroids 2014; 79:64-9. [PMID: 24291637 DOI: 10.1016/j.steroids.2013.11.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 10/28/2013] [Accepted: 11/09/2013] [Indexed: 10/26/2022]
Abstract
The bioflavonoids have effects on vascular smooth muscle and gastrointestinal smooth muscle. The flavone and phytoestrogen, chrysin, has been shown to have a vasorelaxant effect on resistance blood vessels. This effect was mediated by nitric oxide (NO). Chrysin inhibited aromatase/estrogen biosynthesis in postmenopausal women. The purpose of this study was to determine if chrysin had an effect on cholecystokinin- or KCl-induced tension in male guinea pig gallbladder strips. In addition, the second messenger(s) system(s) that mediated the effect were to be determined. A pharmacologic approach was used. Male guinea pig gallbladder strips were placed in in vitro chambers filled with Krebs solution, maintained at 37 °C, and gassed with 95% O2-5% CO2. Changes in tension were recorded using a polygraph. It was shown that the PKA/cAMP second messenger system mediated part of the observed chrysin-induced relaxation of cholecystokinin-induced tension, the PKC system also mediated part of the relaxation, and the inhibition of both extracellular Ca(2+) entry and intracellular Ca(2+) release also mediated the chrysin-induced relaxation. This is the first report of chrysin having an effect on gallbladder smooth muscle contraction.
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Affiliation(s)
- Loren W Kline
- Department of Dentistry, University of Alberta, Edmonton T6G 2N8, Canada; University of Alberta, Department of Physiology, 7-55 Medical Sciences Building, Edmonton T6G 2H7, Alberta, Canada.
| | - Edward Karpinski
- University of Alberta, Department of Physiology, 7-55 Medical Sciences Building, Edmonton T6G 2H7, Alberta, Canada.
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Non-genomic vasorelaxant effects of 17β-estradiol and progesterone in rat aorta are mediated by L-type Ca2+ current inhibition. Acta Pharmacol Sin 2012; 33:615-24. [PMID: 22465948 DOI: 10.1038/aps.2012.4] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
AIM The sex hormones 17β-estradiol (βES) and progesterone (PRG) induce rapid non-genomic vasodilator effects which could be protective for the cardiovascular system. The purpose of this study was to analyze the mechanisms underlying their vasodilator effect in rat aortic smooth muscle preparations. METHODS Endothelium-denuded aorta artery rings were prepared from male Wistar rats and incubated in an organ bath. The contractions of the preparation were recorded through isometric transducers. The effects of the hormones on K(+) current and L-type Ca(2+) current (LTCC) were analyzed by using the whole cell voltage-clamp technique in A7r5 cells. RESULTS Both βES and PRG (1-100 μmol/L) concentration-dependently relaxed the endothelium-denuded aortic rings contracted by (-)-Bay K8644 (0.1 μmol/L) or by KCl (60 mmol/L). The IC(50) values of the two hormones were not statistically different. The K(V) channel blocker 4-aminopyridine (2 mmol/L), BK(Ca) channel blocker tetraethylammonium (1 mmol/L) and K(ATP) channel blocker glibenclamide (10 μmol/L) did not significantly modify the relaxant effect of the hormones. On the other hand, the blockage of the intracellular βES and PRG receptors with estradiol receptor antagonists ICI 182,780 (1 μmol/L) and PRG receptor antagonist mifepristone (30 μmol/L), respectively, did not significantly modify the relaxant action of the hormones. In A7r5 cells, both the hormones (1-100 μmol/L) rapidly and reversibly inhibited the basal and BAY-stimulated LTCC. However, these hormones had no effect on the basal K(+) current. CONCLUSION The vasorelaxant effects of βES and PRG are due to the inhibition of LTCC. The K(+) channels are not involved in the effects.
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Kim EY, Lee YJ, Rhyu MR. Black cohosh (Cimicifuga racemosa) relaxes the isolated rat thoracic aorta through endothelium-dependent and -independent mechanisms. JOURNAL OF ETHNOPHARMACOLOGY 2011; 138:537-542. [PMID: 22001858 DOI: 10.1016/j.jep.2011.09.048] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 09/21/2011] [Accepted: 09/25/2011] [Indexed: 05/31/2023]
Abstract
AIM OF THE STUDY The rhizome of the Cimicifuga racemosa (commonly known as black cohosh) has been used in treatment of climacteric complaints for decades in North America and Europe. A number of studies investigated the estrogenic potential of black cohosh, but its effectiveness is still controversial. Recently, it was reported that the extract of black cohosh acted as an agonist at the serotonin (5-HT) receptor and 5-HT derivative was isolated out of the black cohosh extract. Because it is well known that the 5-HT elicited the various cardiovascular effects including vasorelaxation, we investigated the vasorelaxant effects of the extract of black cohosh and its possible mechanisms of action. MATERIALS AND METHODS The extract of black cohosh (BcEx) was examined for its vasorelaxant effects in isolated rat aorta. The aortic rings were equilibrated under resting tension and induced reproducible contraction in organ bath. The control contraction was produced by 300 nM NE, and then BcEx were added. In experiments where specific inhibitors were used, they were added 20 min before NE contraction. RESULTS BcEx elicited two phases of relaxation in rat aorta pre-contracted with norepinephrine. The first, a rapid relaxation, which occurred within seconds of BcEx administration, was eliminated by pretreatment with N(G)-nitro-l-arginine (l-NNA) or methylene blue. The endogenous NO synthase substrate l-Arg markedly reversed the action of l-NNA, indicating that BcEx elicited the vasorelaxant effect via the NO/cGMP pathway. The second, slowly developing relaxation was not affected by the endothelium denudation. BcEx-induced endothelium-independent vasorelaxation appears to involve the inhibition of calcium influx mediated by the opening of inward rectifier potassium channels. CONCLUSIONS BcEx elicits the vasorelaxant effect via endothelium-dependent and -independent mechanisms and may contribute to a better understanding of a potential link between the use of black cohosh and its beneficial effects on vascular health.
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Affiliation(s)
- Eun-Young Kim
- Functional Food Technology Research Group, Korea Food Research Institute, Gyeonggi-do, Republic of Korea
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19
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Keung W, Chan MLY, Ho EYW, Vanhoutte PM, Man RYK. Non-genomic activation of adenylyl cyclase and protein kinase G by 17β-estradiol in vascular smooth muscle of the rat superior mesenteric artery. Pharmacol Res 2011; 64:509-16. [PMID: 21641998 DOI: 10.1016/j.phrs.2011.05.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 05/20/2011] [Indexed: 10/18/2022]
Abstract
The aim of the present study was to investigate the signaling mechanisms underlying the non-genomic effects of estrogen in rat superior mesenteric arteries. Isometric tension was recorded in rings with or without endothelium. Changes in cyclic nucleotide levels and protein kinase (PK) activities were measured. Localization of estrogen receptors (ER) and caveolin-1 were visualized by confocal microscopy. 17β-Estradiol elicited a concentration-dependent relaxation. The relaxation was reduced by SQ 22536 (adenylyl cyclase inhibitor) and KT 5823 (PKG inhibitor) while ODQ (guanylyl cyclase inhibitor) and KT 5720 (PKA inhibitor) had no effect. At the physiological concentration of 1 nM, 17β-estradiol had no significant effect on relaxation but enhanced the relaxation to sodium nitroprusside. The enhancement of relaxation by 17β-estradiol was blocked by SQ 22536 and KT 5823. Although 1 nM 17β-estradiol or 10 nM sodium nitroprusside given alone had minimal effects on PKG activity, in their combined presence, a significant increase in PKG activity was observed. Confocal microscopy demonstrated that ERα and ERβ colocalized with caveolin-1 and PKG in vascular smooth muscle cells. The present findings suggest that 17β-estradiol enhances relaxation of vascular smooth muscle of the rat superior mesenteric artery by activating adenylyl cyclase, leading to an increase in cAMP which cross activates PKG in the caveolae. No detectable increase in total cAMP level was detected as these changes occurred in the caveolae. These results are consistent with the notion that 17β-estradiol mediates its effect in the distinct microdomains of the caveolae of the plasma membrane with colocalization of adenylyl cyclase and PKG.
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Affiliation(s)
- Wendy Keung
- Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong, China
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20
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Kim EY, Kim JH, Rhyu MR. Endothelium-independent vasorelaxation by Ligusticum wallichii in isolated rat aorta: comparison of a butanolic fraction and tetramethylpyrazine, the main active component of Ligusticum wallichii. Biol Pharm Bull 2010; 33:1360-3. [PMID: 20686232 DOI: 10.1248/bpb.33.1360] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ligusticum wallichii is an herb widely used to treat vascular disorders in Asian countries, and tetramethylpyrazine (TMP) has been identified as one of its vasorelaxant active components. This study was performed to examine the endothelium-independent relaxation produced by the butanol-soluble fraction of L. wallichii extract (LwBt) and its possible mechanisms of action in isolated rat aortic rings. The effects were compared with those of TMP. LwBt produced vasorelaxation that increased gradually after 2-3 min of LwBt administration and reached a maximum within 30 min. LwBt-induced relaxation was significantly attenuated by pretreatment with 4-aminopyridine and apamin. Additionally, LwBt attenuated CaCl(2)-induced vasoconstriction in high-potassium depolarized medium. Thus, LwBt-induced vasorelaxation apparently involved inhibition of calcium influx, mediated by the opening of voltage-dependent and/or Ca(2+)-activated potassium channels. On the other hand, the effect of TMP was significantly attenuated by pretreatment with glibenclamide, and 4-aminopyridine had no effect. In conclusion, LwBt-induced endothelium-independent vasorelaxation was mediated by the opening of voltage-dependent potassium channels, while TMP-induced relaxation was mediated by the opening of ATP-dependent potassium channels. These effects of LwBt may be due to a substance other than TMP.
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Affiliation(s)
- Eun-Young Kim
- Food Function Research Division, Korea Food Research Institute, Gyeonggido 463-746, Korea
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Hill BJF, Gebre S, Schlicker B, Jordan R, Necessary S. Nongenomic inhibition of coronary constriction by 17ß-estradiol, 2-hydroxyestradiol, and 2-methoxyestradiol. Can J Physiol Pharmacol 2010; 88:147-52. [PMID: 20237589 DOI: 10.1139/y09-120] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The cardioprotective effects of 17beta-estradiol (E2) in women are hypothesized to be partially mediated by the E2 metabolites 2-hydroxyestradiol (2-HOE) and 2-methoxyestradiol (2-MeOH). Therefore, the purpose of our study was to determine the acute effects of E2, 2-HOE, and 2-MeOH on inhibition of coronary arterial constriction. Right coronary arteries obtained from breeding sows were cut into 4 mm rings and suspended in organ baths. Incubation of the rings with E2, 2-HOE, and 2-MeOH (10 micromol/L) for 60 min attenuated a subsequent KCl-induced contraction by approximately 50%. The protein synthesis inhibitor cycloheximide and the estrogen receptor antagonists ICI 182780 and tamoxifen did not affect the attenuation. Moreover, E2, 2-HOE, and 2-MeOH antagonized the contraction induced by the vasospasm agonist endothelin-1 (0.1 micromol/L) by approximately 36%. When the L-type Ca2+ channel blocker nifedipine was added at the conclusion of the experiment, no additional contractile attenuation was present. Our results suggest that E2, 2-HOE, and 2-MeOH demonstrate a similar nongenomic inhibition of agonist-induced extracellular Ca2+-dependent contractions.
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Affiliation(s)
- Brent J F Hill
- Department of Biology, 201 Donaghey Avenue, University of Central Arkansas, Conway, AR 72035, USA.
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Kim EY, Lee KO, Kim DI, Rhyu MR. Vasorelaxant Activities of Aqueous Extracts from Twenty Medicinal Plants Used in Oriental Medicines in Isolated Rat Aorta. Prev Nutr Food Sci 2010. [DOI: 10.3746/jfn.2010.15.3.189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Kim EY, Rhyu MR. Synergistic vasorelaxant and antihypertensive effects of Ligusticum wallichii and Angelica gigas. JOURNAL OF ETHNOPHARMACOLOGY 2010; 130:545-551. [PMID: 20669368 DOI: 10.1016/j.jep.2010.05.048] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
AIM OF THE STUDY The synergistic vasorelaxant and antihypertensive effects of Ligusticum wallichii and Angelica gigas were examined in isolated rat aorta rings and spontaneously hypertensive rats (SHRs). MATERIALS AND METHODS The ethanol extract of Ligusticum wallichii (LwEx) or Angelica gigas (AgEx) or their combinations at ratios Ligusticum wallichii:Angelica gigas = 1:1 (MxEx11), 1:3 (MxEx13), and 3:1 (and MxEx31), and their successive water soluble (LwDw, AgDw, MxDw11, MxDw13 and MxDw31) or n-butanol soluble fractions (LwBt, AgBt, MxBt11, MxBt13, and MxBt31) were examined for their vasorelaxant effects. In an antihypertensive study, LwEx, AgEx, or MxEx11 (100 mg/kg) was orally administered to SHRs, and the systolic, diastolic, and mean blood pressure were measured using the tail-cuff method before and 1, 3, 5, 7, and 24 h after oral administration. RESULTS Each of the ethanol extracts caused long-term relaxation in endothelium-intact or endothelium-denuded rat aorta preconstricted with norepinephrine (NE, 300 nM). All of the water phases of the ethanol extracts elicited an endothelium-dependent acute relaxation, and the water phase of MxDw11 (EC50 values: 1.08 mg/mL, P < 0.05) had the highest activity. MxDw11-induced acute relaxation was abolished by pretreatment with N(G)-nitro-L-arginine (10 microM), methylene blue (1.0 microM), or atropine (0.1 microM), indicating that the response to MxDw involves the enhancement of the nitric oxide-cGMP system. On the other hand, all of the butanol phases showed an endothelium-independent long-term relaxation, and MxBt11 (85 +/- 7% relaxation of NE-preconstricted active tone at 20 min after the addition, P < 0.05) displayed the highest activity. MxBt11-induced gradual relaxation was significantly attenuated by an inward rectifier potassium-channel inhibitor, but not by an ATP-sensitive or a large conductance Ca2+-activated potassium-channel blocker. Calcium concentration-dependent contraction curves in high-potassium, depolarizing medium were shifted significantly to the right and downward after incubation with MxBt11 (0.03, 0.1, and 0.3 mg/mL), implying that MxBt11 is also involved in the inhibition of extracellular calcium influx to vascular smooth muscle. MxEx11 (100 mg/kg) significantly reduced systolic blood pressure of SHRs at 3, 5, and 7 h after oral administration, but this effect was not induced by Ligusticum wallichii or Angelica gigas alone. CONCLUSIONS The combination of Ligusticum wallichii and Angelica gigas elicits a synergistic effect on vasorelaxation in isolated rat aortas and antihypertension in SHRs. The ratio of Ligusticum wallichii: Angelica gigas = 1:1 was the most effective of all combinations tested.
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Affiliation(s)
- Eun-Young Kim
- Food Function Research Division, Korea Food Research Institute, Bundang-gu, Seongnam-si, Gyeonggi-do 463-746, Republic of Korea
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Flinsenberg TWH, van der Sterren S, van Cleef ANH, Schuurman MJ, Agren P, Villamor E. Effects of sex and estrogen on chicken ductus arteriosus reactivity. Am J Physiol Regul Integr Comp Physiol 2010; 298:R1217-24. [PMID: 20164203 DOI: 10.1152/ajpregu.00839.2009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sex hormones have an important influence on cardiovascular physiology and pathophysiology and sex differences in vascular reactivity have been widely demonstrated. In the present study we hypothesized 1) the presence of sexual dimorphism in chicken ductus arteriosus (DA) responsiveness to contractile and relaxant stimuli and 2) that estrogens are vasoactive in the chicken DA. In vitro contractions (assessed with a wire myograph) induced by normoxia, KCl, 4-aminopyridine, norepinephrine, phenylephrine, U46619, or endothelin-1, as well as relaxations induced by ACh, sodium nitroprusside, BAY 41-2272, PGE(2), isoproterenol, forskolin,Y-27632, and hydroxyfasudil were not significantly different between males and females. The estrogen 17beta-estradiol elicited concentration-dependent relaxation of KCl-, phenylephrine-, and oxygen-induced active tone in male and female chicken DA. The stereoisomer 17alpha-estradiol showed lesser relaxant effects, and the selective estrogen receptor (ER) agonists 4,4',4''-(4-propyl-[(1)H]pyrazole-1,3,5-triyl)tris-phenol (ERalpha) and 2,3-bis(4-hydroxyphenyl)-propionitrile (ERbeta) did not show any effect. There were no sex differences in the responses to estrogen. Endothelium removal or the presence of the soluble guanylate cyclase inhibitor ODQ, the K(+) channel blockers tetraethylammonium, glibenclamide, and charybdotoxin, or the ER antagonist fulvestrant did not modify 17beta-estradiol-induced relaxation. CaCl(2) (30 muM-10 mM) induced concentration-dependent contraction in DA rings depolarized by 62.5 mM KCl or stimulated with 21% O(2) in Ca(2+)-free medium. Preincubation with 17beta-estradiol or the L-type Ca(2+) channel blocker nifedipine produced an inhibition of CaCl(2)-induced contractions. In conclusion, there are no sex-related differences in chicken DA reactivity. The estrogen 17beta-estradiol induces an endothelium-independent relaxation of chicken DA that is not mediated by ER activation. This relaxant effect is, at least partially, due to inhibition of Ca(2+) entry from extracellular space.
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Affiliation(s)
- Thijs W H Flinsenberg
- Department of Pediatrics, Maastricht University Medical Center, GROW School for Oncology and Developmental Biology, P. Debyelaan 25, Maastricht, The Netherlands
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Hogan AM, Kennelly R, Collins D, Baird AW, Winter DC. Oestrogen inhibits human colonic motility by a non-genomic cell membrane receptor-dependent mechanism. Br J Surg 2009; 96:817-22. [DOI: 10.1002/bjs.6612] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Abstract
Background
Classical effects of oestrogen involve activation of target genes after binding nuclear receptors. Oestrogenic effects too rapid for DNA transcription (non-genomic) are known to occur. The effect of oestrogen on colonic motility is unknown despite the prevalence of gastrointestinal symptoms in pregnant and premenopausal women.
Methods
Histologically normal colon was obtained from proximal resection margins of colorectal carcinoma specimens. Circular smooth muscle strips were microdissected and suspended in organ baths under 1 g of tension. After equilibration, they were exposed to 17β-oestradiol (n = 8) or bovine serum albumin (BSA)-conjugated 17β-oestradiol (n = 8). Fulvestrant, an oestrogen receptor antagonist, was added to some baths (n = 8). Other strips were exposed to calphostin C or cycloheximide. Carbachol was added in increasing concentrations and contractile activity was recorded isometrically.
Results
Oestrogen inhibited colonic contractility (mean difference 19·7 per cent; n = 8, P < 0·001). In keeping with non-genomic, rapid-onset steroid action, the effect was apparent within minutes and reversible. It was observed with both 17β-oestradiol and BSA-conjugated oestrogen, and was not altered by cycloheximide. Effects were inhibited by fulvestrant, suggesting receptor mediation.
Conclusion
Oestrogen decreases contractility in human colonic smooth muscle by a non-genomic mechanism involving cell membrane coupling.
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Affiliation(s)
- A M Hogan
- Institute for Clinical Outcomes Research and Education, St Vincent's University Hospital, Dublin, Ireland
- College of Life Sciences, University College Dublin, Dublin, Ireland
| | - R Kennelly
- Institute for Clinical Outcomes Research and Education, St Vincent's University Hospital, Dublin, Ireland
- College of Life Sciences, University College Dublin, Dublin, Ireland
| | - D Collins
- Institute for Clinical Outcomes Research and Education, St Vincent's University Hospital, Dublin, Ireland
- College of Life Sciences, University College Dublin, Dublin, Ireland
| | - A W Baird
- College of Life Sciences, University College Dublin, Dublin, Ireland
| | - D C Winter
- Institute for Clinical Outcomes Research and Education, St Vincent's University Hospital, Dublin, Ireland
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Babaei H, Azarmi Y. 17beta-estradiol inhibits calcium-dependent and -independent contractions in isolated human saphenous vein. Steroids 2008; 73:844-50. [PMID: 18486173 DOI: 10.1016/j.steroids.2008.04.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2007] [Revised: 02/22/2008] [Accepted: 04/01/2008] [Indexed: 12/13/2022]
Abstract
Studies suggest that estrogen modulate vascular reactivity but at present its exact mechanism of action has yet to be clarified. The aim of this study was to evaluate the effect of 17beta-estradiol (E2) on calcium-dependent and -independent contractions induced in the human saphenous veins (HSVs). HSVs were obtained from patients undergoing coronary artery bypass graft surgery. The ability of E2 to modulate Ca(2+) entry was assessed by obtaining concentration-response curve to CaCl(2) in the absence or presence of E2. In other experiments intracellular Ca(2+) was depleted by repeated application of phenylephrine in the presence of cyclopiazonic acid (CPA). Then, at the plateau of PGF(2alpha) contraction, E2 or nifedipine (NIF) was added. Involvement of protein kinase C (PKC) in relaxant effect of E2 was evaluated by application of phorbol-12,13-dibutyrate (PDBu) in normal or Ca(2+)-free Krebs' solution. When the contraction was obtained, E2 or NIF was added. In Ca(2+)-free hyperpolarizing solution, pretreatment with E2, concentration dependently reduced contractions induced by cumulative addition of calcium chloride. Furthermore, E2 elicited relaxant effects on the PGF(2alpha)-induced contractions in Ca(2+)-free solution in the presence or absence of CPA. Both E2 and NIF produced significant relaxation in HSV rings contracted by direct activation of PKC in Krebs' solution. However, in Ca(2+)-free solution, NIF failed to induce relaxant effect but E2 kept its effect on the PDBu-induced contraction. These results suggest that the relaxant effect of E2 on HSV is elicited by calcium-dependent and -independent pathways. The calcium-independent pathway may involve PKC inhibition.
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Affiliation(s)
- Hossein Babaei
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
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27
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Diez-Perez A. Selective estrogen receptor modulators (SERMS). ACTA ACUST UNITED AC 2007; 50:720-34. [PMID: 17117297 DOI: 10.1590/s0004-27302006000400017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2006] [Accepted: 06/10/2006] [Indexed: 11/22/2022]
Abstract
Hormone receptors and, specifically, estrogen receptors were described about four decades ago. For estrogens, there are two receptors, estrogen receptor alpha (ERalpha) and estrogen receptor beta (ERbeta). The two receptors are coded by different genes and their tissue expression varies across organs. ERalpha is predominantly expressed in reproductive tissues (uterus, breast, ovaries) liver and central nervous system, whereas ERbeta is expressed in other tissues such as bone, endothelium, lungs, urogenital tract, ovaries, central nervous system and prostate. More than seventy molecules that belong to the SERMS class have been described. There are 5 chemical groups: triphenylethylenes, benzotiophenes, tetrahydronaphtylenes, indoles and benzopyrans. All of these non-hormonal compounds are capable of activating the ER, reduce bone turnover rate and, as an antiresorptive, clearly improve bone density. Estrogens reduce bone turnover rate and, as an antiresorptive, clearly improve bone density. They are also beneficial for the relief of menopausal symptoms. An ongoing debate that extends over the decades, relates to to overall benefit/risk profile of estrogen or estrogen-progestin therapy since these therapies can increase the risk of serious health disorders, such as breast cancer. SERMs have increased our understanding of hormone-receptor regulatory mechanisms. Their development has permitted a targeted efficacy profile avoiding some of the side effects of the hormone therapy. Their clinical utility relies today mostly on the effects on breast cancer and bone.
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Affiliation(s)
- Adolfo Diez-Perez
- Department of Internal Medicine, Autonomous University of Barcelona, Hospital del Mar-URFOA-IMIM, Barcelona, Spain.
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Otto C, Wessler S, Fritzemeier KH. Exploiting Nongenomic Estrogen Receptor-Mediated Signaling for the Development of Pathway-Selective Estrogen Receptor Ligands. ACTA ACUST UNITED AC 2007:163-81. [PMID: 17824177 DOI: 10.1007/2789_2006_022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2023]
Abstract
Different molecular mechanisms mediate the diverse biological effects of estrogens. The classical genomic mechanism is based on the function of the ER as a ligand-dependent transcription factor that binds to estrogen-response elements (EREs) in promoters of target genes to initiate gene expression. These direct genomic effects play a prominent role in the regulation of reproductive function. In contrast, nongenomic effects mediated by the classical ER have been demonstrated to activate PI3K, leading to the activation of endothelial NOS (eNOS) and hence vasorelaxation. Pathway-selective ER ligands might represent a novel option for hormone replacement therapy. Here we describe the identification and in vitro characterization of tool compounds that bind the ER reasonably well but exhibit low transcriptional activity on ERE-driven promoters. However, these compounds behave as potent stimulators of PI3K/Akt activation in vitro and lead to aortic vessel relaxation, a mechanism that is thought to be driven by nongenomic ER action. In a second set of experiments, we analyze how the in vitro pathway selectivity translates into the in vivo situation. We examine our tool compounds in comparison to estradiol and estren in the following paradigms: bone protection, uterine growth assays, and mammary gland assays.
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Affiliation(s)
- C Otto
- TRG Gynecology and Andrology, Bayer Schering Pharma AG, Müllerstr. 178, 13342 Berlin, Germany.
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29
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Uji M, Yoshida KI, Shintani-Ishida K, Morimoto K. Sex difference in norepinephrine surge in response to psychological stress through nitric oxide in rats. Life Sci 2006; 80:860-6. [PMID: 17173936 DOI: 10.1016/j.lfs.2006.11.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2006] [Revised: 10/19/2006] [Accepted: 11/03/2006] [Indexed: 11/24/2022]
Abstract
Psychological stress elevates blood pressure through sympathetic nerve activation. This pressor response is supposedly associated with cardiovascular events. We investigated a sex difference in the pressor response and norepinephrine surge to cage-switch stress in rats. Wistar male and female rats were catheterized for blood pressure monitoring and blood sampling. Six days post-surgery, the rats were exposed to the cage-switch stress and blood samples were collected at rest and 30 min after the start of the stress. The stress-induced pressor response was greater in the male than in the female rats. The stress significantly increased the norepinephrine level in the male, but not in the female rats. Pre-treatment with N(G)-nitro-l-arginine methyl ester (L-NAME), a nitric oxide (NO) synthase inhibitor, attenuated the norepinephrine response significantly in the male rats. There was no sex difference in the endothelial NO synthase expression in the gastrocnemius muscle. However the phosphorylation at serine 1177, a marker for eNOS activation, was higher in the male than in the female rats. These results suggest that NO is involved in the norepinephrine surge to psychological stress in the male rats, but not in the female rats. This is the first report on a sex difference in the norepinephrine surge in response to psychological stress through NO, in association with pressor response.
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Affiliation(s)
- Masami Uji
- Department of Environmental Health, Faculty of Life Science and Human Technology, Nara Women's University, Kita-Uoya Nishi-machi, Nara 630-8506, Japan
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30
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Tummala S, Hill BJF. The enhanced endothelin-1-induced contraction in cultured coronary arteries from mature female pigs is not antagonized by 17beta-estradiol. Vascul Pharmacol 2006; 46:346-52. [PMID: 17240201 PMCID: PMC1924796 DOI: 10.1016/j.vph.2006.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2006] [Revised: 11/14/2006] [Accepted: 12/01/2006] [Indexed: 11/16/2022]
Abstract
We have previously reported that organ cultured coronary arteries from market-age pigs (6-9 months of age) exhibit an enhanced contraction to the atherosclerotic-associated peptide, endothelin-1 (ET-1). The objective of this study was to investigate the interaction of 17beta-estradiol with ET-1 in organ cultured coronary arteries from older female pigs (3-4 years old). A cumulative concentration-response relationship (1 x 10(-9) M to 3 x 10(-7) M) was generated to ET-1, and the isometric tension measured in fresh and organ cultured (4 days at 37 degrees C) arterial rings that were each pre-incubated for 50 min in different concentrations (1 x 10(-9) M to 1 x 10(-5) M) of 17beta-estradiol. Compared to freshly used arteries, culturing induced a 2-fold increase in tension development to ET-1 (3 x 10(-7) M). Although 17beta-estradiol previously relaxed pre-constricted (with a 60 mM KCl solution) arteries, it did not affect the constrictive response to ET-1. Also, using an ET-1 ELISA we found that 17beta-estradiol did not effect ET-1 production in intact arteries. Our results indicate that 17beta-estradiol does not attenuate the production and constrictive properties of ET-1 in coronary arteries demonstrating a dedifferentiated cell phenotype.
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Affiliation(s)
- Saigiridhar Tummala
- Department of Biology, University of Central Arkansas, 201 Donaghey Avenue, Conway, AR 72035, USA
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31
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Rhyu MR, Kim EY, Yoon BK, Lee YJ, Chen SN. Aqueous extract of Schizandra chinensis fruit causes endothelium-dependent and -independent relaxation of isolated rat thoracic aorta. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2006; 13:651-7. [PMID: 16704926 DOI: 10.1016/j.phymed.2006.02.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
An aqueous extract of Schizandra chinensis fruit (ScEx) has long been used to promote the vascular health of postmenopausal women in Korea. This study investigated the ability of ScEx to relax rat aorta constricted with norepinephrine (NE) and the mechanism(s) of such relaxation. ScEx induced partial, endothelium-dependent relaxation. In particular, the relaxation induced by lower concentrations of ScEx (0.1 and 0.3 mg/ml) was largely endothelium-dependent, and was essentially abolished by NG-nitro-L-arginine, methylene blue, 1H-[1,2,3] oxadiazole [4,4-a] quinoxalin-1-one, indomethacin, or ICI 182,780. The results indicate that the response to ScEx involves enhancement of the nitric oxide (NO)-cGMP system, and that it occurs via estrogen receptors. The magnitude of the inhibition with these treatments decreased with increasing ScEx concentration, however, indicating that other vasorelaxation mechanisms are involved, which depend on the ScEx concentration. Calcium concentration-dependent contraction curves in high potassium depolarization medium were shifted significantly to the right and downward after incubation with ScEx (0.3 and 1.0 mg/ml), implying that ScEx is also involved in inhibition of the extracellular calcium influx to vascular smooth muscle. These data demonstrate that ScEx caused both endothelium-dependent and -independent vasorelaxation, which may contribute to understanding the cardiovascular protective effect of ScEx.
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Affiliation(s)
- M R Rhyu
- Food Function Research Division, Korea Food Research Institute, Gyeonggi-Do 463-420, Korea.
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Rhyu MR, Kim JH, Kim EY. Radix angelica elicits both nitric oxide-dependent and calcium influx-mediated relaxation in rat aorta. J Cardiovasc Pharmacol 2006; 46:99-104. [PMID: 15965361 DOI: 10.1097/01.fjc.0000164092.88821.49] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
This study examined the vascular relaxation produced by Radix Angelica (AG; Dong Quai) and its possible mechanisms in isolated rat aortic rings precontracted with norepinephrine. The butanolic fraction (AgBt) of the crude extract of AG causes gradual endothelium-independent relaxation, which was unaffected by five different potassium channel inhibitors. AgBt attenuated the CaCl2-induced vasoconstriction in high-potassium depolarized medium; this required less than one-tenth the concentration needed to elicit vascular relaxation. An aqueous fraction (AgDw) of the crude extract induced transient acute relaxation, which was virtually abolished by endothelial ablation and pretreatment with L-NNA. L-Arginine fully reversed the action of L-NNA. Methylene blue and atropine significantly attenuated the relaxation, but indomethacin did not. Ferulic acid, the main active component in AG, relaxed both endothelium-intact and -denuded rings, while L-NNA, methylene blue, or atropine did not modify the relaxation. Ferulic acid also did not attenuate the CaCl2-induced contraction in high-potassium depolarized medium. In conclusion, Radix Angelica leads to both endothelium-dependent and -independent relaxation of isolated rat aorta. Increased formation of NO might contribute to the endothelium-mediated relaxation, while inhibition of the calcium influx might be an important mechanism in direct smooth muscle relaxation. A substance other than ferulic acid might create these effects.
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Affiliation(s)
- Mee-Ra Rhyu
- Function Research Division, Korea Food Research Institute, Gyeonggi-Do, Korea.
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Cruz MN, Douglas G, Gustafsson JA, Poston L, Kublickiene K. Dilatory responses to estrogenic compounds in small femoral arteries of male and female estrogen receptor-β knockout mice. Am J Physiol Heart Circ Physiol 2006; 290:H823-9. [PMID: 16183727 DOI: 10.1152/ajpheart.00815.2005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The objectives of this study were to determine whether acute dilatory responses to estrogen receptor agonists are altered in isolated arteries from estrogen receptor β-deficient mice (β-ERKO) and to gain insight into the role of nitric oxide (NO) in these responses. Femoral arteries (∼250 μm) from male and female β-ERKO mice and wild-type (WT) littermates (26 female, 13 in each group; and 24 male, 12 in each group) were mounted on a Multi-Myograph. Concentration-response curves to 17β-estradiol (17β-E2) and the selective estrogen receptor-α (ER-α) agonist propyl-[1H]-pyrazole-1,3,5-triy-trisphenol (PPT) were obtained before and after NO synthase (NOS) inhibition [ Nω-nitro-l-arginine methyl ester (l-NAME), 0.1 mM] in arteries preconstricted with U-46619 (a thromboxane analog). In WT mice, responses to the potent estrogen receptor-β (ER-β) agonist 2,3-bis(4-hydroxyphenyl)-propionitrile (DPN) and the contribution of NO were also assessed. Concentration-response curves to 17β-E2and PPT were similar in arteries from WT and β-ERKO mice of both genders, but NO-mediated relaxation was different, since l-NAME reduced 17β-E2mediated relaxation in arteries from male and female β-ERKO but not WT mice ( P < 0.05). NOS inhibition reduced dilation to PPT in arteries from male and female WT mice, as well as arteries from female β-ERKO mice ( P < 0.05). Responses to DPN in arteries from WT female and male mice did not differ after NOS inhibition. The acute dilatory responses to estrogenic compounds are similar in WT and β-ERKO mice but differ mechanistically. Because NO appeared to contribute to responses to 17β-E2in arteries from β-ERKO but not WT mice, the presence of ER-β apparently inhibits ER-α-mediated NO relaxation.
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Affiliation(s)
- Maria Natalia Cruz
- Institution for Clinical Science, Intervention, and Technology, Division of Obstetrics and Gynecology, Karolinska Institutet, Huddinge, 14186 Stockholm, Sweden
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King JT, Lovell PV, Rishniw M, Kotlikoff MI, Zeeman ML, McCobb DP. Beta2 and beta4 subunits of BK channels confer differential sensitivity to acute modulation by steroid hormones. J Neurophysiol 2006; 95:2878-88. [PMID: 16436475 DOI: 10.1152/jn.01352.2005] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Membrane-associated receptors for rapid, steroidal neuromodulation remain elusive. Estradiol has been reported to facilitate activation of voltage- and Ca(2+)-dependent BK potassium channels encoded by Slo, if associated with beta1 subunits. We show here that 1) multiple members of the beta family confer sensitivity to multiple steroids on BK channels, 2) that beta subunits differentiate between steroids, and 3) that different betas have distinct relative preferences for particular steroids. Expressed in HEK 293 cells, inside-out patches with channels composed of Slo-alpha alone showed no steroid sensitivity. Cells expressing alphabeta4 exhibited potent, rapid, reversible, and dose-dependent potentiation by corticosterone (CORT; a glucocorticoid), and were potentiated to a lesser degree by other sex and stress steroids. In contrast, alphabeta2 channels were potentiated more strongly by dehydroepiandrosterone (DHEA; an enigmatic, stress-related adrenal androgen), and to a lesser extent by CORT, estradiol, testosterone, and DHEA-S. Cholesterol had no effect on any BK channel compositions tested. Conductance-voltage plots of channels composed of alpha plus beta2 or beta4 subunits were shifted in the negative direction by steroids, indicating greater activation at negative voltages. Thus our results argue that the variety of Slo-beta subunit coexpression patterns occurring in vivo expands the repertoire of Slo channel gating in yet another dimension not fully appreciated, rendering BK gating responsive to dynamic fluctuations in a multiple of steroid hormones.
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Affiliation(s)
- J T King
- Department of Neurobiology and Behavior, Cornell University, W153 Mudd Hall, Ithaca, NY 14853, USA
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Wessler S, Otto C, Wilck N, Stangl V, Fritzemeier KH. Identification of estrogen receptor ligands leading to activation of non-genomic signaling pathways while exhibiting only weak transcriptional activity. J Steroid Biochem Mol Biol 2006; 98:25-35. [PMID: 16203130 DOI: 10.1016/j.jsbmb.2005.08.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2004] [Accepted: 08/11/2005] [Indexed: 12/27/2022]
Abstract
Estrogen receptors (ERs) stimulate genomic effects by acting as nuclear transcription factors as well as non-genomic effects by activating distinct cytoplasmic protein kinase cascades. Non-genomic effects have been implicated in numerous cellular processes, such as proliferation, differentiation, apoptosis and vasorelaxation. To exploit non-genomic effects mediated by ERalpha for novel hormone replacement regimens, we screened a focused library of steroid receptor ligands to identify compounds exhibiting properties different from estradiol, i.e. substances that selectively stimulate non-genomic signal transduction pathways while exhibiting low genomic activities. Treatment of breast cancer cells and osteosarcoma cells with estradiol, estren, substance A and substance B led to non-genomic activation of Akt (protein kinase B) and extracellular signal-regulated kinase 1/2 (ERK1/2) signaling cascades mediated by Src (Rous Sarcoma Virus, non-receptor tyrosine kinase) and phosphatidylinositol-3-kinase (PI3K) stimulation. Such compounds leading to prominent Akt/ERK activation but exhibiting only weak genomic properties were applied in vasorelaxation assays, modeling physiological non-genomic ER responses. As expected from PI3K and Src activation data, substances were as effective as estradiol in mediating vasorelaxation. We assume that these pathway-selective estrogen receptor ligands may serve as potent lead structures for novel hormone replacement strategies exhibiting lesser side effects than the existing treatment paradigms.
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Affiliation(s)
- Silja Wessler
- Paul-Ehrlich-Institute, Paul-Ehrlich Strasse 51-59, D-63225 Langen, Germany.
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Korstjens IJM, Smolders RGV, van der Mooren MJ, Kloosterboer HJ, Kenemans P, Sipkema P. Endothelium-dependent dilatory effects of 3α-OH-tibolone in gracilis muscle arterioles of the female Wistar rat. Menopause 2005; 12:340-7. [PMID: 15879924 DOI: 10.1097/01.gme.0000146714.59224.c1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Tibolone is a synthetic steroid used for the treatment of the symptoms of menopause that, once metabolized, has estrogenic, progestogenic, and androgenic properties. We investigated the direct vasodilatory effects of the major active tibolone metabolite 3alpha-OH-tibolone and its sulfated form on female rat skeletal muscle arterioles, which play an important role in the control of blood pressure. DESIGN In isolated, pressurized spontaneously constricted arterioles (mean passive diameter 83 +/- 3 microm), we investigated the vasodilatory effect of 3alpha-OH-tibolone and its sulfated form. To study the role of the endothelium and in particular that of nitric oxide, we repeated the experiments with 3alpha-OH-tibolone after removal of the endothelium and on vessels pretreated with the nitric oxide synthesis inhibitor, Nomega-nitro-L-arginine (L-Na). Finally we compared the vasodilatory effect of 3alpha-OH-tibolone with 17beta-estradiol. RESULTS A dose-dependent dilatation to 3alpha-OH-tibolone was observed starting at a concentration of 10 M. With the sulfated form of 3alpha-OH-tibolone, dilatation was only present at the highest concentration (10 M). In the denuded vessels, the vasodilatory effect was absent at concentrations from 10 to 10 M. The dilatation induced by 3alpha-OH-tibolone was not significantly reduced by L-Na. The vasodilatory effect of 3alpha-OH-tibolone did not differ from that of 17beta-estradiol. CONCLUSIONS 3alpha-OH-tibolone has a dose-dependent vasodilatory effect on isolated skeletal muscle arterioles from the rat. The sulfated form has no vasodilatory effect in this setup. This finding suggests that during this short incubation time there was no conversion of the sulfated metabolite into its active form by the vascular endothelium. The vasodilatory effect of 3alpha-OH-tibolone is endothelium dependent at physiologic concentrations and comparable to that of 17beta-estradiol.
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Dambros M, van Koeveringe GA, Bast A, van Kerrebroeck PEV. Relaxant effects of estradiol through non-genomic pathways in male and female pig bladder smooth muscle. Pharmacology 2005; 72:121-7. [PMID: 15331918 DOI: 10.1159/000080184] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2004] [Accepted: 03/23/2004] [Indexed: 11/19/2022]
Abstract
The precise effect of low estrogen levels on urinary bladder contractility remains controversial. The present study was designed to analyze the effect of 17beta-estradiol in bladder smooth muscle contractility and the involvement of specific estrogen receptor stimulation in this effect. Castrated male and female pig detrusor strips were mounted for tension recording in an organ bath, superfused with Krebs solution at 37 degrees C and stimulated electrically and pharmacologically. In order to verify the acute effect of 17beta-estradiol on muscle contractility, the strips were incubated with different concentrations of the hormone. Muscle contractions were induced by potassium chloride, acetylcholine chloride and electrical field stimulation. The involvement of the estrogen receptor in the effects of 17beta-estradiol was assessed by incubation of some strips with the selective estrogen receptor antagonist ICI 182.780 before estradiol was applied. Estradiol at a dose of 30 micromol/l elicited a lower amplitude of contractions induced by EFS, Ach and KCl in female as well as in castrated male pig bladder smooth muscle strips. The effects of 17beta-estradiol were stronger in contractions induced by potassium chloride than those induced by other forms of stimulation. Pre-treatment with the pure estrogen receptor antagonist had no effect on 17beta-estradiol-induced inhibition of muscle contractility. These observations suggest that 17beta-estradiol induces lower amplitude of contraction of female as well as castrated male pig detrusor which is not mediated by the classic estrogen receptor. Furthermore, we can conclude that estradiol has a stronger inhibitory effect on the depolarization of muscle cell membrane compared to a muscarinic receptor-induced contraction.
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Affiliation(s)
- Miriam Dambros
- Department of Urology, Maastricht University, Maastricht, The Netherlands
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38
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Díaz M, Ramírez CM, Marin R, Marrero-Alonso J, Gómez T, Alonso R. Acute relaxation of mouse duodenum [correction of duodenun] by estrogens. Evidence for an estrogen receptor-independent modulation of muscle excitability. Eur J Pharmacol 2005; 501:161-78. [PMID: 15464075 DOI: 10.1016/j.ejphar.2004.08.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2004] [Revised: 08/05/2004] [Accepted: 08/09/2004] [Indexed: 11/17/2022]
Abstract
17-beta-Estradiol, the stereoisomer 17-alpha-estradiol and the synthetic estrogen diethylstilbestrol (DES), all caused a rapid (<3 min) dose-dependent reversible relaxation of mouse duodenal spontaneous activity, reduced basal tone and depressed the responses to CaCl(2) and KCl. The steroidal antiestrogen 7alpha-[9-[(4,4,5,5,5,-pentafluoropenty)sulphinyl]nonyl]-estra-1,3,5(19)-triene-3,17beta-diol (ICI182,780) failed to either mimic or prevent the effect of 17-beta-estradiol. The effect of estrogens was unrelated to activation of nitric oxide (NO), mitogen-activated protein kinase (MAPK), protein kinase A (PKA), protein kinase G (PKG) or protein kinase C (PKC). Estrogen-induced relaxation was partially reversed by 1,4-dihydro-2,6-dimethyl-5-nitro-4-[2-(trifluoromethyl)phenyl]-pyridine-3-carboxilic acid methyl ester (BAY-K8644), depolarization, or by application of tetraethylammonium or 4-aminopyridine, but not by glibenclamide, apamin, charybdotoxin, paxilline or verruculogen. The effects of BAY-K8644 and K(+) channel blockers were synergistic, and allowed relaxed tissues to recover spontaneous activity and basal tone. We hypothesize that the rapid non-genomic spasmolytic effect of estrogens on mouse duodenal muscle might be triggered by an estrogen-receptor-independent mechanism likely involving activation of tetraethylamonium- and 4-aminopyridine-sensitive K(+) channels and inhibition of L-type Ca2(+) channels on the smooth muscle cells.
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Affiliation(s)
- Mario Díaz
- Departamento de Biología Animal, Laboratorio de Fisiología Animal, Facultad de Biología, Universidad de La Laguna, 38206 Tenerife, Spain.
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Lee HA, Seong Y, Lee WJ, Kim I. 17beta-Estradiol inhibits calcium-dependent, but not calcium-independent, contraction in isolated rat aorta. Naunyn Schmiedebergs Arch Pharmacol 2005; 371:152-7. [PMID: 15692818 DOI: 10.1007/s00210-004-1017-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2004] [Accepted: 12/20/2004] [Indexed: 11/26/2022]
Abstract
It is now well known that 17beta-estradiol has an endothelium-independent, non-genomic vasorelaxant effect. We hypothesized that 17beta-estradiol has its non-genomic effect on calcium-independent contraction in de-endothelialized rat aortic rings. Rat aortic ring preparations were mounted in organ baths and exposed to contractile agents. 17beta-Estradiol (8, 20 or 50 microM), but not 17alpha-estradiol, concentration-dependently decreased the tension induced by 1.0 microM phenylephrine (PE) in the presence, but not in the absence, of calcium in the solution. Pretreatment with 17beta-estradiol concentration-dependently inhibited vascular contractions induced by cumulative addition of PE or calcium and almost completely abolished those induced by cumulative addition of Bay K8644, a calcium channel opener. Furthermore, 17beta-estradiol also concentration-dependently decreased the tension induced by 0.3 microM phorbol 12,13-dibutyrate (PDBu), a protein kinase C activator, in the presence of calcium in the solution, but not in the absence of calcium in the solution. Pretreatment with 17beta-estradiol had little effect on vascular contractions induced by PDBu or PE or on PE-induced mitogen-activated protein kinase (MAPK) activation in calcium-free Krebs solution. These results suggest that 17beta-estradiol inhibits calcium-dependent, but not calcium-independent, vascular contraction.
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Affiliation(s)
- Hae-Ahm Lee
- Department of Physiology, Kyungpook National University School of Medicine, Daegu 700-422, Republic of Korea
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Xia Y, Krukoff TL. Estrogen induces nitric oxide production via activation of constitutive nitric oxide synthases in human neuroblastoma cells. Endocrinology 2004; 145:4550-7. [PMID: 15242984 DOI: 10.1210/en.2004-0327] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Although it is becoming increasingly evident that nitric oxide (NO) mediates some of estrogen's actions in the brain, the effects of estrogen on NO production through NO synthases (NOS) in neuronal cells have not yet been identified. Here we assessed changes in NO production induced by 17beta-estradiol (E2) in cells of neuronal origin using human SK-N-SH neuroblastoma cells, which we show express all three isoforms of NOS. Involvement of NOS isoforms in E2-induced NO production was examined using isoform-specific NOS inhibitors. E2 (10(-10)-10(-6) m) induced rapid increases in NO release and changes in endothelial NOS (eNOS) expression, which were blocked by ICI 182,780, an antagonist of estrogen receptors. Increased levels of NO release and NOS activity induced by E2 were blocked by N5-(1-Imino-3-butenyl)-L-ornithine, a neuronal NOS inhibitor, and N(5)-(1-Iminoethyl)-L-ornithine, an eNOS inhibitor, but not by 1400W, an inducible NOS inhibitor. These results demonstrate that E2-stimulated NO production occurs via estrogen receptor-mediated activation of the constitutive NOSs, neuronal NOS and eNOS. The E2-induced NO increase was abolished when extracellular Ca2+ was removed from the medium or after the addition of nifedipine, an L-type channel blocker, and was partially inhibited using 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester, an intracellular Ca2+ chelator. However, 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester itself also caused an increase in NO release that was blocked by 1400W, suggesting that inducible NOS mediates this response. Together these data reveal that constitutive NOS activities are responsible for E2-induced NO production in neuroblastoma cells and that differential activation of NOS isoforms in these cells occurs in response to different treatments.
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Affiliation(s)
- Yun Xia
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
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41
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Tep-areenan P, Kendall DA, Randall MD. Mechanisms of vasorelaxation to 17beta-oestradiol in rat arteries. Eur J Pharmacol 2003; 476:139-49. [PMID: 12969759 DOI: 10.1016/s0014-2999(03)02152-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have investigated the involvement of the endothelium, K+ channels, oestradiol receptors, and Ca2+ influx in 17beta-oestradiol-induced vasorelaxation in rat mesenteric arterial beds and aortae. 17beta-Oestradiol (10 pM-1 mM) caused acute vasorelaxations in mesenteric arterial beds and aortae from male and female rats. In male rat mesenteric vessels and aortae, the vasorelaxations were mostly independent of the endothelium and nitric oxide (NO). However, indomethacin (10 microM) enhanced the relaxant responses to 17beta-oestradiol. In male rat mesenteric beds, 60 mM KCl, tetrabutylammonium chloride (300 microM), 4-aminopyridine (1 mM), and barium chloride (30 microM), charybdotoxin (100 nM), but not glibenclamide (10 microM) and tamoxifen (10 microM), inhibited vasorelaxation to 17beta-oestradiol. In male rat aortae, 60 mM KCl did not affect vasorelaxation to 17beta-oestradiol. However, in the presence of indomethacin, vasorelaxation to 17beta-oestradiol was enhanced but this was sensitive to 60 mM KCl. Pre-treatment with 17beta-oestradiol (100 microM) inhibited CaCl2-induced contraction. The present findings indicate that, in rat mesenteric beds and aortae, 17beta-oestradiol causes acute and potent vasorelaxation which may be enhanced in the presence of a cyclooxygenase inhibitor. In mesenteric arterial bed, 17beta-oestradiol-induced vasorelaxation occurs primarily via activation of K+ channels. In the aorta, vasorelaxations involved activation of K+ efflux when the cyclooxygenase pathway was inhibited, and also inhibition of Ca2+ influx.
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Affiliation(s)
- Patcharin Tep-areenan
- School of Biomedical Sciences, E-Floor, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK
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Tep-areenan P, Kendall DA, Randall MD. Mechanisms of vasorelaxation to testosterone in the rat aorta. Eur J Pharmacol 2003; 465:125-32. [PMID: 12650841 DOI: 10.1016/s0014-2999(03)01453-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We have investigated the role of endothelium-derived relaxing factors, K(+) channels and steroid receptors in vasorelaxation to testosterone in the rat aorta. Testosterone (1 nM-mM) caused acute concentration-dependent vasorelaxation. Both indomethacin (10 microM) and flurbiprofen (10 microM) uncovered relaxant responses to testosterone. The action of indomethacin was inhibited by endothelial removal. N(G)-nitro-L-arginine methyl ester (L-NAME, 300 microM) had no effects on testosterone-induced responses. In the presence of indomethacin, the vasorelaxant potency of testosterone was reduced by depolarization with 60 mM KCl or charybdotoxin (100 nM), but not by glibenclamide (10 microM), 4-aminopyridine (1 mM) or barium chloride (30 microM). The responses to testosterone were not inhibited by flutamide (10 microM) or mifepristone (30 microM). Pre-treatment of the aorta with testosterone (100 microM) inhibited CaCl(2)-induced contraction. In the present study, we have demonstrated that testosterone causes acute vasorelaxations, which are modulated via endothelium-derived prostanoids. The responses uncovered by cyclooxygenase inhibitors are due to the activation of K(Ca) channels, while at higher concentrations, testosterone inhibits Ca(2+) influx.
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Affiliation(s)
- Patcharin Tep-areenan
- Queen's Medical Centre, School of Biomedical Sciences, University of Nottingham Medical School, Nottingham NG7 2UH, UK
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Abstract
Estrogen has long been observed to endow cardiovascular protective effects, as evidenced by sex-specific differences in the incidence of hypertensive and coronary artery disease, the development of atherosclerosis, and myocardial remodeling after infarction. To exert its tissue-specific effects, the classic estrogen receptor (ER) functions as a ligand-dependent transcription factor. However, there is growing evidence that in response to 17beta-estradiol and heterologous signals, the ER can also mediate signaling cascades at the membrane and in the cytoplasm via various second messengers, such as receptor-mediated protein kinases. This review summarizes the current understanding of nonnuclear ER signaling and discusses the relevance to eliciting the beneficial cardiovascular effects of estrogen. These include vasodilation, inhibition of response to vessel injury, limiting myocardial injury after infarction, and attenuating cardiac hypertrophy. Defining the full repertoire of ER function promises to expose novel, highly specific targets for pharmacological interventions and may ultimately lead to the primary and secondary prevention of cardiovascular diseases.
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Affiliation(s)
- Karen J Ho
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, Mass 02139, USA
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