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Fleischer AW, Schalk JC, Wetzel EA, Hanson AM, Sem DS, Donaldson WA, Frick KM. Long-term oral administration of a novel estrogen receptor beta agonist enhances memory and alleviates drug-induced vasodilation in young ovariectomized mice. Horm Behav 2021; 130:104948. [PMID: 33571507 PMCID: PMC8680219 DOI: 10.1016/j.yhbeh.2021.104948] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 12/09/2020] [Accepted: 01/19/2021] [Indexed: 01/11/2023]
Abstract
Development of estrogen therapies targeting the β (ERβ) but not α (ERα) estrogen receptor is critically needed for the treatment of negative menopausal symptoms, as ERα activation increases health risks like cancer. Here, we determined the effects of long-term oral treatment with EGX358, a novel highly selective ERβ agonist, on memory, vasodilation, and affect in young ovariectomized mice. Mice were orally gavaged daily for 9 weeks with vehicle, 17β-estradiol (E2), the ERβ agonist diarylpropionitrile (DPN), or EGX358 at doses that enhance memory when delivered acutely. Tail skin temperature was recorded as a proxy for vasodilation following injection of vehicle or senktide, a tachykinin receptor 3 agonist used to model hot flashes. Anxiety-like behavior was assessed in the open field (OF) and elevated plus maze (EPM), and depression-like behavior was measured in the tail suspension (TST) and forced swim tests (FST). Finally, memory was assessed in object recognition (OR) and object placement (OP) tasks. E2, DPN, and EGX358 reduced senktide-mediated increases in tail skin temperature compared to vehicle. All three treatments also enhanced memory in the OR and OP tasks, whereas vehicle did not. Although E2 increased time spent in the center of the OF, no other treatment effects were observed in the OF, EPM, TST, or FST. These data suggest that long-term ERβ activation can reduce hot flash-like symptoms and enhance spatial and object recognition memories in ovariectomized mice. Thus, the highly selective ERβ agonist EGX358 may be a promising avenue for reducing menopause-related hot flashes and memory dysfunction.
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Affiliation(s)
- Aaron W Fleischer
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States of America.
| | - Jayson C Schalk
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States of America.
| | - Edward A Wetzel
- Department of Chemistry, Marquette University, Milwaukee, WI 53201-1881, United States of America.
| | - Alicia M Hanson
- Department Pharmaceutical Sciences, Concordia University Wisconsin, Mequon, WI 53097, United States of America; Center for Structure-Based Drug Design and Development, Concordia University Wisconsin, Mequon, WI 53097, United States of America.
| | - Daniel S Sem
- Department Pharmaceutical Sciences, Concordia University Wisconsin, Mequon, WI 53097, United States of America; Center for Structure-Based Drug Design and Development, Concordia University Wisconsin, Mequon, WI 53097, United States of America.
| | - William A Donaldson
- Department of Chemistry, Marquette University, Milwaukee, WI 53201-1881, United States of America.
| | - Karyn M Frick
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States of America.
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Uchida M, Kobayashi O. Novel effect of α-lactalbumin on the yohimbine-induced hot flush increase of the tail skin temperature in ovariectomized rats. Biosci Biotechnol Biochem 2018; 82:862-868. [PMID: 29504865 DOI: 10.1080/09168451.2018.1444976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
5-Hydroxytryptamine (5-HT) and noradrenaline have been thought to play important roles in the mechanism of hot flush. Then, to clarify the relation between serotonergic and adrenergic nervous systems on the mechanism of hot flush, the effect of paroxetine, 5-HT reuptake inhibitor (SSRI) was evaluated on the yohimbine-induced hot flush increase of tail skin temperature in ovariectomized female rats. Yohimbine (adrenaline α2 antagonist) significantly increased the tail skin temperature in course of time. Clonidine (adrenaline α2 agonist) significantly attenuated this effect. Paroxetine also significantly inhibited the increase of tail skin temperature by yohimbine. α-Lactalbumin having SSRI activity in vitro study also significantly inhibited the increase of tail skin temperature, but not significantly decreased the initial temperature. This difference may explain the different mechanism between paroxetine (SSRI) and α-lactalbumin, suggesting new mechanism of hot flush.
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Affiliation(s)
- Masayuki Uchida
- Food Science & Technology Research Laboratories, R&D Division, Meiji Co., Ltd., Tokyo, Japan
| | - Orie Kobayashi
- Food Science & Technology Research Laboratories, R&D Division, Meiji Co., Ltd., Tokyo, Japan
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Krajewski-Hall SJ, Blackmore EM, McMinn JR, Rance NE. Estradiol alters body temperature regulation in the female mouse. Temperature (Austin) 2017; 5:56-69. [PMID: 29687044 DOI: 10.1080/23328940.2017.1384090] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Revised: 09/18/2017] [Accepted: 09/18/2017] [Indexed: 10/18/2022] Open
Abstract
Hot flushes are due to estrogen withdrawal and characterized by the episodic activation of heat dissipation effectors. Recent studies (in humans and rats) have implicated neurokinin 3 (NK3) receptor signaling in the genesis of hot flushes. Although transgenic mice are increasingly used for biomedical research, there is limited information on how 17β-estradiol and NK3 receptor signaling alters thermoregulation in the mouse. In this study, a method was developed to measure tail skin temperature (TSKIN) using a small data-logger attached to the surface of the tail, which, when combined with a telemetry probe for core temperature (TCORE), allowed us to monitor thermoregulation in freely-moving mice over long durations. We report that estradiol treatment of ovariectomized mice reduced TCORE during the light phase (but not the dark phase) while having no effect on TSKIN or activity. Estradiol also lowered TCORE in mice exposed to ambient temperatures ranging from 20 to 36°C. Unlike previous studies in the rat, estradiol treatment of ovariectomized mice did not reduce TSKIN during the dark phase. Subcutaneous injections of an NK3 receptor agonist (senktide) in ovariectomized mice caused an acute increase in TSKIN and a reduction in TCORE, consistent with the activation of heat dissipation effectors. These changes were reduced by estradiol, suggesting that estradiol lowers the sensitivity of central thermoregulatory pathways to NK3 receptor activation. Overall, we show that estradiol treatment of ovariectomized mice decreases TCORE during the light phase, reduces the thermoregulatory effects of senktide and modulates thermoregulation differently than previously described in the rat.
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Affiliation(s)
- Sally J Krajewski-Hall
- Departments of Pathology (S.J.K-H., E.M.B., J.R.M. and N.E.R.), Cellular and Molecular Medicine (N.E.R.), Neurology (N.E.R.) and the Evelyn F. McKnight Brain Institute (N.E.R.) University of Arizona College of Medicine, Tucson, AZ, USA
| | - Elise M Blackmore
- Departments of Pathology (S.J.K-H., E.M.B., J.R.M. and N.E.R.), Cellular and Molecular Medicine (N.E.R.), Neurology (N.E.R.) and the Evelyn F. McKnight Brain Institute (N.E.R.) University of Arizona College of Medicine, Tucson, AZ, USA
| | - Jessi R McMinn
- Departments of Pathology (S.J.K-H., E.M.B., J.R.M. and N.E.R.), Cellular and Molecular Medicine (N.E.R.), Neurology (N.E.R.) and the Evelyn F. McKnight Brain Institute (N.E.R.) University of Arizona College of Medicine, Tucson, AZ, USA
| | - Naomi E Rance
- Departments of Pathology (S.J.K-H., E.M.B., J.R.M. and N.E.R.), Cellular and Molecular Medicine (N.E.R.), Neurology (N.E.R.) and the Evelyn F. McKnight Brain Institute (N.E.R.) University of Arizona College of Medicine, Tucson, AZ, USA
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Zingue S, Tchoumtchoua J, Ntsa DM, Sandjo LP, Cisilotto J, Nde CBM, Winter E, Awounfack CF, Ndinteh DT, Clyne C, Njamen D, Halabalaki M, Creczynski-Pasa TB. Estrogenic and cytotoxic potentials of compounds isolated from Millettia macrophylla Benth (Fabaceae): towards a better understanding of its underlying mechanisms. Altern Ther Health Med 2016; 16:421. [PMID: 27784319 PMCID: PMC5396542 DOI: 10.1186/s12906-016-1385-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 10/05/2016] [Indexed: 11/10/2022]
Abstract
Background Millettia macrophylla was previously reported to have estrogenic effects and to prevent postmenopausal osteoporosis in Wistar rats. So, the study deals with the identification of its secondary metabolites and the evaluation of their estrogenicity and cytotoxicity toward tumoural cells. Thus, 13 known compounds were obtained from successive chromatographic columns and identified by NMR data compared to those previously reported. Methods In vitro estrogenicity of the isolates and the phenolic fraction (PF) of M. macrophylla were performed by E-screen and reporter gene assays, while their cytotoxicity was evaluated by Alamar Blue (resazurin) assay. A 3-days uterotrophic assay and the ability of PF to alleviate hot flushes in ovariectomized adult rats were tested in vivo. Results Seven of the 13 secondary metabolites turned to be estrogenic. Only two exhibited cytotoxic effects on MCF-7 and MDA-MB-231 with CC50 values of 110 μM and 160 μM, respectively. PF induced a significant (p < 0.01) MCF-7 cells proliferation and transactivated both ERα and ERβ in the reported gene assay at 10−2 μg/mL. In vivo, PF acted more efficiently than the methanol crude extract, resulting to a significant (p < 0.01) increase in the uterine wet weight, uterine protein level, uterine and vaginal epithelial height at the dose of 10 mg/kg BW. In addition, PF reduced the average duration and frequency of hot flushes induced in rat. Conclusion These aforementioned results indicate that PF is a good candidate for the preparation of an improved traditional medicine able to alleviate some menopausal complaints such as vaginal dryness and hot flushes. Graphical abstract Estrogenic and cytotoxic potentials of compounds isolated from Millettia macrophylla Benth. (Fabaceae): towards a better understanding of its underlying mechanism![]() Electronic supplementary material The online version of this article (doi:10.1186/s12906-016-1385-5) contains supplementary material, which is available to authorized users.
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Ahn NR, Leem YH, Kato M, Chang HK. Effects of creatine monohydrate supplementation and exercise on depression-like behaviors and raphe 5-HT neurons in mice. J Exerc Nutrition Biochem 2016; 20:24-31. [PMID: 27757384 PMCID: PMC5067422 DOI: 10.20463/jenb.2016.09.20.3.4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 08/28/2016] [Accepted: 09/01/2016] [Indexed: 12/17/2022] Open
Abstract
[Purpose] The effects of creatine and exercise on chronic stress-induced depression are unclear. In the present study, we identified the effects of 4-week supplementation of creatine monohydrate and/or exercise on antidepressant behavior and raphe 5-HT expression in a chronic mild stress-induced depressed mouse model. [Methods] Seven-week-old male C57BL/6 mice (n=48) were divided randomly into 5 groups: (1) non-stress control (CON, n=10), (2) stress control (ST-CON, n=10), (3) stress and creatine intake (ST-Cr, n=10), (4) stress and exercise (ST-Ex, n=9), and (5) combined stress, exercise, and creatine intake (ST-Cr+Ex, n=9). After five weeks’ treatment, we investigated using both anti-behavior tests (the Tail Suspension Test (TST) and the Forced Swimming Test (FST)), and 5-HT expression in the raphe nuclei (the dorsal raphe (DR) and median raphe (MnR)). [Results] Stress for 4 weeks significantly increased depressive behaviors in the mice. Treatment with creatine supplementation combined with exercise significantly decreased depressive behaviors as compared with the CON-ST group in both the TST and FST tests. With stress, 5-HT expression in the raphe nuclei decreased significantly. With combined creatine and exercise, 5-HT positive cells increased significantly and had a synergic effect on both DR and MnR. [Conclusion] The present study found that even a single treatment of creatine or exercise has partial effects as an antidepressant in mice with chronic mild stress-induced depression. Furthermore, combined creatine and exercise has synergic effects and is a more effective prescription than a single treatment.
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Affiliation(s)
- Na-Ri Ahn
- Laboratory of Exercise Physiology, Department of Human Movement Science, Seoul Women's University, Seoul Republic of Korea
| | - Yea-Hyun Leem
- Department of Neuroscience and TIDRC, Ewha Womans University Medical Center, Seoul Republic of Korea
| | - Morimasa Kato
- Department of Health and Nutrition, Yonezawa Nutrition University of Yamagata Prefecture, Yonezawa Japan
| | - Hyuk-ki Chang
- Laboratory of Exercise Physiology, Department of Human Movement Science, Seoul Women's University, Seoul Republic of Korea
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Treatment with an orally bioavailable prodrug of 17β-estradiol alleviates hot flushes without hormonal effects in the periphery. Sci Rep 2016; 6:30721. [PMID: 27477453 PMCID: PMC4967894 DOI: 10.1038/srep30721] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 07/06/2016] [Indexed: 11/15/2022] Open
Abstract
Estrogen deprivation has a profound effect on the female brain. One of the most obvious examples of this condition is hot flushes. Although estrogens relieve these typical climacteric symptoms, many women do not want to take them owing to unwanted side-effects impacting, for example, the uterus, breast and blood. Therefore, there is a need for developing safer estrogen therapies. We show here that treatment with 10β,17β-dihydroxyestra-1,4-dien-3-one (DHED), a novel brain-targeting bioprecursor prodrug of the main human estrogen, 17β-estradiol, alleviates hot flushes in rat models of thermoregulatory dysfunction of the brain. Oral administration of DHED elicits a significant reduction of tail skin temperature (TST) rise representing hot flushes in the morphine-dependent ovariectomized rat model and results in the restoration of estrogen deprivation-induced loss of diurnal rhythm in TST. These beneficial effects occur without detrimental peripheral hormonal exposure; thus, the treatment avoids potentially harmful stimulation of estrogen-sensitive peripheral organs, including the uterus and the anterior pituitary, or the proliferation of MCF-7a breast cancer cell xenografts. Our promising preclinical assessments warrant further considerations of DHED for the development of a brain-selective 17β-estradiol therapy to relieve hot flushes without undesirable peripheral side-effects.
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Zingue S, Michel T, Tchatchou J, Chantal Beatrice Magne N, Winter E, Monchot A, Awounfack CF, Djiogue S, Clyne C, Fernandez X, Creczynski-Pasa TB, Njamen D. Estrogenic effects of Ficus umbellata Vahl. (Moraceae) extracts and their ability to alleviate some menopausal symptoms induced by ovariectomy in Wistar rats. JOURNAL OF ETHNOPHARMACOLOGY 2016; 179:332-344. [PMID: 26771069 DOI: 10.1016/j.jep.2016.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Revised: 12/30/2015] [Accepted: 01/02/2016] [Indexed: 06/05/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Ficus umbellata Vahl. (Moraceae) is a medicinal plant used in Cameroon to treat amenorrhea as well as other physiological disorders related to menopause. AIM OF STUDY In order to justify scientifically its traditional use, the estrogen-like properties of the aqueous (AE) and methanol (MeOH) extracts of F. umbellata were investigated. MATERIAL AND METHODS In vitro, the ability of different extracts of F. umbellata to activate estrogen receptors α (ERα) and β (ERβ) in cell-based reporter gene assays using human embryonic kidney (HEK293T) cells transfected with ERs was tested. In vivo, a 3-day uterotrophic assay and the capacity of the extracts to alleviate hot flushes in ovariectomized adult rats were tested. Using a bioassay-guided fractionation the major compound of F. umbellata was isolated and tested in vitro on HEK293T-ERα and ERβ cells. RESULTS AE and MeOH extracts significantly altered ERα as well as ERβ activities. In vivo, both extracts significantly increase the uterine and vaginal epithelium thickness, and uterine total protein levels in a dose dependent manner. Interestingly, both extracts of F. umbellata at the dose of 100 mg/kg BW significantly decreased the total number, average duration as well as frequency of hot flushes in experimental rats compared to age-matched OVX controls. Finally, 7-methylumbelliferone, a coumarin was characterized as the major compound of F. umbellata; however this compound did not transactivate ERα as well ERβ in vitro. CONCLUSION These aforementioned results suggest that F. umbellata extracts as used by the traditional practitioner have estrogen-like effects and may alleviate some menopausal problems such as vaginal dryness and hot flushes.
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Affiliation(s)
- Stéphane Zingue
- Department of Life and Earth Sciences, Higher Teachers' Training College, University of Maroua, P.O. Box 55, Maroua, Cameroon; Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde I, P.O. Box 812, Yaounde, Cameroon
| | - Thomas Michel
- Institute of Chemistry of Nice, Faculty of Science, University Nice Sophia-Antipolis, UMR CNRS 7272, Valrose Park, F-06108 Nice Cedex 2, Nice, France
| | - Jules Tchatchou
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde I, P.O. Box 812, Yaounde, Cameroon
| | | | - Evelyn Winter
- Department of Pharmaceutical Sciences, Health Sciences Centre, Federal University of Santa Catarina, CEP 88040-900 Florianópolis, SC, Brazil
| | - André Monchot
- Institute of Chemistry of Nice, Faculty of Science, University Nice Sophia-Antipolis, UMR CNRS 7272, Valrose Park, F-06108 Nice Cedex 2, Nice, France
| | - Charline Florence Awounfack
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde I, P.O. Box 812, Yaounde, Cameroon
| | - Sefirin Djiogue
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde I, P.O. Box 812, Yaounde, Cameroon
| | - Colin Clyne
- Hudson Institute of Medical Research, 27-31 Wright Street Clayton, VIC 3168, Australia
| | - Xavier Fernandez
- Institute of Chemistry of Nice, Faculty of Science, University Nice Sophia-Antipolis, UMR CNRS 7272, Valrose Park, F-06108 Nice Cedex 2, Nice, France
| | - Tânia Beatriz Creczynski-Pasa
- Department of Pharmaceutical Sciences, Health Sciences Centre, Federal University of Santa Catarina, CEP 88040-900 Florianópolis, SC, Brazil
| | - Dieudonné Njamen
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde I, P.O. Box 812, Yaounde, Cameroon.
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Petrova ES, Afanasova AI. Software tools for data modelling and processing of human body temperature circadian dynamics. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2015:3287-90. [PMID: 26736994 DOI: 10.1109/embc.2015.7319094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This paper is presenting a software development for simulating and processing thermometry data. The motivation of this research is the miniaturization of actuators attached to human body which allow frequent temperature measurements and improve the medical diagnosis procedures related to circadian dynamics.
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McGregor C, Sau A, Ruddy SC, Leung D, Webb M, Durst T, Wright JS, Lagace D, Pratt MAC. Novel ligands balance estrogen receptor β and α agonism for safe and effective suppression of the vasomotor response in the ovariectomized female rat model of menopause. Endocrinology 2014; 155:2480-91. [PMID: 24823389 DOI: 10.1210/en.2013-1976] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Vasomotor thermo-dysregulation (hot flashes) are an often debilitating symptom of menopause. Effective treatment is achieved primarily through activation of the estrogen receptor (ER)α with estrogens but is also associated with increased risk for breast and uterine cancer. In this study, we have tested novel compounds lacking the B ring of 17-hydroxy-β-estradiol (E2) (A-CD compounds) with differing ratios of ERα:ERβ binding affinities for the ability to reduce diurnal/nocturnal tail-skin temperatures (TSTs) in the ovariectomized female rat menopausal hot flash model. Normal mammary tissue expresses the predominantly antiproliferative ERβ. Therefore, we hypothesized that a preferential ERβ agonist with fractional ERα activity would safely reduce TSTs. The A-CD compound, L17, is a preferential ERβ agonist that has a ratio of ERβ:ERα binding affinity relative to E2 of 9.3 (where ERβ:ERα for E2, 1.0). In the ovariectomized rat, daily administration of low doses (1 mg/kg) of the A-CD compound TD81 (ERα:ERβ relative affinity, 15.2) was ineffective in temperature regulation, whereas L17 showed a trend toward TST reduction. Both E2 and the A-CD compound, TD3 (ERβ:ERα relative affinity, 5.0), also reduced TSTs but had marked proliferative effects on mammary and uterine tissues. At 2 mg/kg, L17 strongly reduced TSTs even more effectively than E2 but, importantly, had only minimal effect on uterine weight and mammary tissues. Both E2- and L17-treated rats showed similar weight reduction over the treatment period. E2 is rapidly metabolized to highly reactive quinones, and we show that L17 has 2-fold greater metabolic stability than E2. Finally, L17 and E2 similarly mediated induction of c-fos expression in neurons within the rat thermoregulatory hypothalamic median preoptic nucleus. Thus, the A-CD compound, L17, may represent a safe and effective approach to the treatment of menopausal hot flashes.
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Affiliation(s)
- Chelsea McGregor
- Department of Cellular and Molecular Medicine (C.M., A.S., S.C.R., D.La., M.A.C.P.), and University of Ottawa Neuroscience Institute (D.La.), University of Ottawa, Ottawa, Ontario, Canada K1H 8M5; Centre for Drug Research and Development (D.Le., M.W.), Vancouver, British Columbia, Canada V6T 1Z3; Department of Chemistry (T.D.), University of Ottawa, Ottawa, Ontario, Canada K1N 6N5; and Department of Chemistry (J.S.W.), Carleton University, Ottawa, Ontario, K1S 5B6 Canada
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Rance NE, Dacks PA, Mittelman-Smith MA, Romanovsky AA, Krajewski-Hall SJ. Modulation of body temperature and LH secretion by hypothalamic KNDy (kisspeptin, neurokinin B and dynorphin) neurons: a novel hypothesis on the mechanism of hot flushes. Front Neuroendocrinol 2013; 34:211-27. [PMID: 23872331 PMCID: PMC3833827 DOI: 10.1016/j.yfrne.2013.07.003] [Citation(s) in RCA: 192] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 07/09/2013] [Accepted: 07/12/2013] [Indexed: 12/31/2022]
Abstract
Despite affecting millions of individuals, the etiology of hot flushes remains unknown. Here we review the physiology of hot flushes, CNS pathways regulating heat-dissipation effectors, and effects of estrogen on thermoregulation in animal models. Based on the marked changes in hypothalamic kisspeptin, neurokinin B and dynorphin (KNDy) neurons in postmenopausal women, we hypothesize that KNDy neurons play a role in the mechanism of flushes. In the rat, KNDy neurons project to preoptic thermoregulatory areas that express the neurokinin 3 receptor (NK3R), the primary receptor for NKB. Furthermore, activation of NK₃R in the median preoptic nucleus, part of the heat-defense pathway, reduces body temperature. Finally, ablation of KNDy neurons reduces cutaneous vasodilatation and partially blocks the effects of estrogen on thermoregulation. These data suggest that arcuate KNDy neurons relay estrogen signals to preoptic structures regulating heat-dissipation effectors, supporting the hypothesis that KNDy neurons participate in the generation of flushes.
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Affiliation(s)
- Naomi E Rance
- Department of Pathology and the Evelyn F. McKnight Brain Research Institute, University of Arizona College of Medicine, Tucson, AZ 85724, USA.
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