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Georgescu T. The role of maternal hormones in regulating autonomic functions during pregnancy. J Neuroendocrinol 2023; 35:e13348. [PMID: 37936545 DOI: 10.1111/jne.13348] [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: 11/21/2022] [Revised: 08/24/2023] [Accepted: 09/19/2023] [Indexed: 11/09/2023]
Abstract
Offspring development relies on numerous physiological changes that occur in a mother's body, with hormones driving many of these adaptations. Amongst these, the physiological functions controlled by the autonomic nervous system are required for the mother to survive and are adjusted to meet the demands of the growing foetus and to ensure a successful birth. The hormones oestrogen, progesterone, and lactogenic hormones rise significantly during pregnancy, suggesting they may also play a role in regulating the maternal adaptations linked to autonomic nervous system functions, including respiratory, cardiovascular, and thermoregulatory functions. Indeed, expression of pregnancy hormone receptors spans multiple brain regions known to regulate these physiological functions. This review examines how respiratory, cardiovascular, and thermoregulatory functions are controlled by these pregnancy hormones by focusing on their action on central nervous system circuits. Inadequate adaptations in these systems during pregnancy can give rise to several pregnancy complications, highlighting the importance in understanding the mechanistic underpinnings of these changes and potentially identifying ways to treat pregnancy-associated afflictions using hormones.
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Affiliation(s)
- T Georgescu
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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Issotina Zibrila A, Wang Z, Sangaré-Oumar MM, Zeng M, Liu X, Wang X, Zeng Z, Kang YM, Liu J. Role of blood-borne factors in sympathoexcitation-mediated hypertension: Potential neurally mediated hypertension in preeclampsia. Life Sci 2022; 320:121351. [PMID: 36592790 DOI: 10.1016/j.lfs.2022.121351] [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: 09/29/2022] [Revised: 12/19/2022] [Accepted: 12/27/2022] [Indexed: 01/01/2023]
Abstract
Hypertension remains a threat for society due to its unknown causes, preventing proper management, for the growing number of patients, for its state as a high-risk factor for stroke, cardiac and renal complication and as cause of disability. Data from clinical and animal researches have suggested the important role of many soluble factors in the pathophysiology of hypertension through their neuro-stimulating effects. Central targets of these factors are of molecular, cellular and structural nature. Preeclampsia (PE) is characterized by high level of soluble factors with strong pro-hypertensive activity and includes immune factors such as proinflammatory cytokines (PICs). The potential neural effect of those factors in PE is still poorly understood. Shedding light into the potential central effect of the soluble factors in PE may advance our current comprehension of the pathophysiology of hypertension in PE, which will contribute to better management of the disease. In this paper, we summarized existing data in respect of hypothesis of this review, that is, the existence of the neural component in the pathophysiology of the hypertension in PE. Future studies would address this hypothesis to broaden our understanding of the pathophysiology of hypertension in PE.
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Affiliation(s)
- Abdoulaye Issotina Zibrila
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China; Department of Animal Physiology, Faculty of science and Technology, University of Abomey-Calavi, 06 BP 2584 Cotonou, Benin
| | - Zheng Wang
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, PR China
| | - Machioud Maxime Sangaré-Oumar
- Department of Animal Physiology, Faculty of science and Technology, University of Abomey-Calavi, 06 BP 2584 Cotonou, Benin
| | - Ming Zeng
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China
| | - Xiaoxu Liu
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China
| | - Xiaomin Wang
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China
| | - Zhaoshu Zeng
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China
| | - Yu-Ming Kang
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China.
| | - Jinjun Liu
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China.
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Involvement of Neuropeptide Y within Paraventricular Nucleus in Electroacupuncture Inhibiting Sympathetic Activities in Hypertensive Rats. Int J Hypertens 2022; 2022:9990854. [PMID: 35087687 PMCID: PMC8789434 DOI: 10.1155/2022/9990854] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 01/05/2022] [Indexed: 12/14/2022] Open
Abstract
Although electroacupuncture (EA) has been used to decrease the blood pressure (BP) clinically, the underlying mechanisms are not clearly clarified. This study aimed to assess the hypothesis that EA treatment exerts a hypotensive action via suppressing sympathetic activities and modulating neuropeptide Y (NPY) function within the paraventricular nucleus (PVN) of hypertensive rats. Male Sprague-Dawley rats were selected for the experiment, and the hypertensive models were established by the two-kidney, one-clip (2K1C) method. Then, the rats were randomly assigned to the sham group, 2K1C group, 2K1C plus EA group, and 2K1C plus sham EA group. EA treatment at the acupoints ST36 and ST40 overlying the peroneal nerves was given once a day for 30 days. The radiotelemetry system was applied to collect the arterial BP recordings. Power spectral analyses of BP variability, BP responses to ganglionic blockade, and plasma levels of norepinephrine and epinephrine were performed to assess the changes in sympathetic nerve activity. Real-time PCR and Western blots were carried out to examine the expression of NPY system in the PVN. The responses of PVN microinjection with NPY Y1R antagonist BIBO3304 were detected to check the endogenous NPY tone. The results showed that the enhanced arterial BP and sympathetic activities were effectively reduced by 30 days of EA treatment, and baroreflex sensitivity was improved in 2K1C hypertensive rats. The level of NPY mRNA and protein expression in the PVN was markedly upregulated by EA treatment in 2K1C rats. In addition, the pressor responses of PVN microinjection with NPY Y1R antagonist BIBO3304 in 2K1C models were remarkably augmented by the EA stimulation. Our results indicate that the increased NPY expression and function in the PVN induced by EA treatment contribute to antihypertensive and sympathetic suppression on hypertensive rats. The findings may elucidate the underlying mechanisms of the acupuncture to be a potential therapeutic strategy against hypertension.
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Issotina Zibrila A, Li Y, Wang Z, Zhao G, Liu H, Leng J, Ahasan Ali M, Ampofo Osei J, Kang YM, Liu J. Acetylcholinesterase inhibition with Pyridostigmine attenuates hypertension and neuroinflammation in the paraventricular nucleus in rat model for Preeclampsia. Int Immunopharmacol 2021; 101:108365. [PMID: 34815190 DOI: 10.1016/j.intimp.2021.108365] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 10/30/2021] [Accepted: 11/09/2021] [Indexed: 11/15/2022]
Abstract
Preeclampsia (PE) is characterized by hypertension, autonomic imbalance and inflammation. The subfornical organ (SFO) reportedly relays peripheral inflammatory mediator's signals to the paraventricular nucleus (PVN), a brain autonomic center shown to mediate hypertension in hypertensive rat but not yet in PE rat models. Additionally, we previously showed that Pyridostigmine (PYR), an acetylcholinesterase inhibitor, attenuated placental inflammation and hypertension in PE models. In this study, we investigated the effect of PYR on the activities of these brain regions in PE model. PYR (20 mg/kg/day) was administered to reduced uterine perfusion pressure (RUPP) Sprague-Dawley rat from gestational day (GD) 14 to GD19. On GD19, the mean arterial pressure (MAP) was recorded and samples were collected for analysis. RUPP rats exhibited increased MAP (P = 0.0025), elevated circulating tumor necrosis factor-α (TNF-α, P = 0.0075), reduced baroreflex sensitivity (BRS), increased neuroinflammatory markers including TNF-α, interleukin-1β (IL-1β), microglial activation (P = 0.0039), oxidative stress and neuronal excitation within the PVN and the SFO. Changes in MAP, in molecular and cellular expression induced by RUPP intervention were improved by PYR. The ability of PYR to attenuate TNF-α mediated central effect was evaluated in TNF-α-infused pregnant rats. TNF-α infusion-promoted neuroinflammation in the PVN and SFO in dams was abolished by PYR. Collectively, our data suggest that PYR improves PE-like symptoms in rat by dampening placental ischemia and TNF-α-promoted inflammation and pro-hypertensive activity in the PVN. This broadens the therapeutical potential of PYR in PE.
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Affiliation(s)
- Abdoulaye Issotina Zibrila
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China
| | - Yubei Li
- School of Clinical Medicine, Xi'an Medical University, Xi'an 710021, Shaanxi, PR China
| | - Zheng Wang
- Department of Pharmacology, Xi'an Jiaotong University School of Basic Medical Sciences, Xi'an 710061, Shaanxi, PR China
| | - Gongxiao Zhao
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China
| | - Haotian Liu
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China
| | - Jing Leng
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China
| | - Md Ahasan Ali
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China
| | - James Ampofo Osei
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China
| | - Yu-Ming Kang
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China.
| | - Jinjun Liu
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China.
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Tüten N, Güralp O, Gök K, Hamzaoglu K, Oner YO, Makul M, Bulut H, Irmak K, Tüten A, Malik E. Serum catestatin level is increased in women with preeclampsia. J OBSTET GYNAECOL 2021; 42:55-60. [PMID: 33938370 DOI: 10.1080/01443615.2021.1873922] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Catestatin can inhibit catecholamine release from chromaffin cells and adrenergic neurons. Catestatin can also have a strong vasodilator effect. This may be useful in understanding the pathophysiology of preeclampsia and its treatment. In this study, we investigated the serum catestatin levels in pregnant women with and without preeclampsia. Fifty consecutive women with mild preeclampsia, 50 consecutive women with severe preeclampsia, and 100 consecutive pregnant women with a gestational age-matched (±1 week) uncomplicated pregnancy were evaluated in a cross-sectional study. Mean serum catestatin was significantly increased in the preeclampsia group compared to the control group (290.7 ± 95.5 pg/mL vs. 182.8 ± 72.0 pg/mL). Mean serum catestatin was comparable in mild and severe preeclampsia groups (282.7 ± 97.9 pg/mL vs. 298.7 ± 93.4 pg/mL, p = .431). Serum catestatin levels had positive correlations with systolic and diastolic blood pressure, urea, uric acid, and creatinine. In conclusion, serum catestatin levels are increased in preeclamptic pregnancies compared to gestational age-matched controls.IMPACT STATEMENTWhat is already known on this subject? The role of autonomic nervous system dysregulation in the pathophysiology of preeclampsia is known. The most obvious part of this dysregulation is the sympathetic nervous system activation. The adrenal medulla is one of the locations of the sympathetic nervous system in the body.What do the results of this study add? Serum catestatin levels were found to be correlated with clinical and laboratory data of preeclampsia. This highlights the importance of chromaffin cell secretions in the adrenal medulla in preeclampsia.What are the implications of these findings for clinical practice and/or further research? This study will help understand the role of the adrenal medulla in the autonomic nervous system dysregulation in preeclampsia. Also, control of serum catestatin levels may support the treatment of hypertension in preeclampsia.
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Affiliation(s)
- Nevin Tüten
- Obstetrics and Gynecology Istanbul, Kanuni Sultan Suleyman Education and Research Hospital, Turkey
| | - Onur Güralp
- Carl von Ossietzky Oldenburg University, University Hospital for Gynecology and Obstetrics, Klinikum Oldenburg AöR, Oldenburg, Germany
| | - Koray Gök
- Education and Research Hospital, Obstetrics and Gynecology, Sakarya University, Sakarya, Turkey
| | - Kübra Hamzaoglu
- Department of Obstetrics and Gynecology, Istanbul Cerrahpasa University, Istanbul, Turkey
| | - Yahya Ozgün Oner
- Department of Obstetrics and Gynecology, Istanbul Cerrahpasa University, Istanbul, Turkey
| | - Melike Makul
- Department of Obstetrics and Gynecology, Istanbul Cerrahpasa University, Istanbul, Turkey
| | - Huri Bulut
- Faculty of Medicine, Medical Biochemistry Department, Istinye University, Istanbul, Turkey
| | - Kübra Irmak
- Department of Obstetrics and Gynaecology, Tokat State Hospital, Tokat, Turkey
| | - Abdullah Tüten
- Department of Obstetrics and Gynecology, Istanbul Cerrahpasa University, Istanbul, Turkey
| | - Eduard Malik
- Carl von Ossietzky Oldenburg University, University Hospital for Gynecology and Obstetrics, Klinikum Oldenburg AöR, Oldenburg, Germany
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Ladyman SR, Brooks VL. Central actions of insulin during pregnancy and lactation. J Neuroendocrinol 2021; 33:e12946. [PMID: 33710714 PMCID: PMC9198112 DOI: 10.1111/jne.12946] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 01/24/2021] [Accepted: 01/27/2021] [Indexed: 12/17/2022]
Abstract
Pregnancy and lactation are highly metabolically demanding states. Maternal glucose is a key fuel source for the growth and development of the fetus, as well as for the production of milk during lactation. Hence, the maternal body undergoes major adaptations in the systems regulating glucose homeostasis to cope with the increased demand for glucose. As part of these changes, insulin levels are elevated during pregnancy and lower in lactation. The increased insulin secretion during pregnancy plays a vital role in the periphery; however, the potential effects of increased insulin action in the brain have not been widely investigated. In this review, we consider the impact of pregnancy on brain access and brain levels of insulin. Moreover, we explore the hypothesis that pregnancy is associated with site-specific central insulin resistance that is adaptive, allowing for the increases in peripheral insulin secretion without the consequences of increased central and peripheral insulin functions, such as to stimulate glucose uptake into maternal tissues or to inhibit food intake. Conversely, the loss of central insulin actions may impair other functions, such as insulin control of the autonomic nervous system. The potential role of low insulin in facilitating adaptive responses to lactation, such as hyperphagia and suppression of reproductive function, are also discussed. We end the review with a list of key research questions requiring resolution.
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Affiliation(s)
- Sharon R Ladyman
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
| | - Virginia L Brooks
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR, USA
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Guerra DD, Hurt KJ. Gasotransmitters in pregnancy: from conception to uterine involution. Biol Reprod 2020; 101:4-25. [PMID: 30848786 DOI: 10.1093/biolre/ioz038] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 02/14/2019] [Accepted: 03/06/2019] [Indexed: 12/13/2022] Open
Abstract
Gasotransmitters are endogenous small gaseous messengers exemplified by nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H2S or sulfide). Gasotransmitters are implicated in myriad physiologic functions including many aspects of reproduction. Our objective was to comprehensively review basic mechanisms and functions of gasotransmitters during pregnancy from conception to uterine involution and highlight future research opportunities. We searched PubMed and Web of Science databases using combinations of keywords nitric oxide, carbon monoxide, sulfide, placenta, uterus, labor, and pregnancy. We included English language publications on human and animal studies from any date through August 2018 and retained basic and translational articles with relevant original findings. All gasotransmitters activate cGMP signaling. NO and sulfide also covalently modify target protein cysteines. Protein kinases and ion channels transduce gasotransmitter signals, and co-expressed gasotransmitters can be synergistic or antagonistic depending on cell type. Gasotransmitters influence tubal transit, placentation, cervical remodeling, and myometrial contractility. NO, CO, and sulfide dilate resistance vessels, suppress inflammation, and relax myometrium to promote uterine quiescence and normal placentation. Cervical remodeling and rupture of fetal membranes coincide with enhanced oxidation and altered gasotransmitter metabolism. Mechanisms mediating cellular and organismal changes in pregnancy due to gasotransmitters are largely unknown. Altered gasotransmitter signaling has been reported for preeclampsia, intrauterine growth restriction, premature rupture of membranes, and preterm labor. However, in most cases specific molecular changes are not yet characterized. Nonclassical signaling pathways and the crosstalk among gasotransmitters are emerging investigation topics.
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Affiliation(s)
- Damian D Guerra
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado, USA
| | - K Joseph Hurt
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado, USA.,Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado, USA
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Reyes LM, Khurana R, Usselman CW, Busch SA, Skow RJ, Boulé NG, Davenport MH, Steinback CD. Sympathetic nervous system activity and reactivity in women with gestational diabetes mellitus. Physiol Rep 2020; 8:e14504. [PMID: 32633077 PMCID: PMC7338594 DOI: 10.14814/phy2.14504] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
INTRODUCTION Gestational diabetes mellitus (GDM) is associated with vascular dysfunction. Sympathetic nervous system activity (SNA) is an important regulator of vascular function, and is influenced by glucose and insulin. The association between GDM and SNA (re)activity is unknown. We hypothesize that women with GDM would have increased SNA during baseline and during stress. METHODS Eighteen women with GDM and 18 normoglycemic pregnant women (controls) were recruited. Muscle SNA (MSNA; peroneal microneurography) was assessed at rest, during a cold pressor test (CPT) and during peripheral chemoreflex deactivation (hyperoxia). Spontaneous sympathetic baroreflex gain was quantified versus diastolic pressure at rest and during hyperoxia. RESULTS Age, gestational age (third trimester) and pre-pregnancy body mass index and baseline MSNA was not different among the groups. Women with GDM had a similar increase in MSNA, but a greater pressor response to CPT compared to controls (% change in MAP 17 ± 7% vs. 9 ± 9%; p = .004). These data are consistent with a greater neurovascular transduction in GDM (% change in total peripheral resistance/% change in burst frequency [BF]: 15.9 ± 30.2 vs. -5.2 ± 16.4, p = .03). Interestingly, women with GDM had a greater reduction in MSNA during hyperoxia (% change in BF -30 ± 19% vs. -6 ± 17%; p = .01). CONCLUSION Women diagnosed with GDM have similar basal SNA versus normoglycemic pregnant women, but greater neurovascular transduction, meaning a greater influence of the sympathetic nerve activity in these women. We also document evidence of chemoreceptor hyperactivity, which may influence SNA in women with GDM but not in controls.
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Affiliation(s)
- Laura M. Reyes
- Program for Pregnancy and Postpartum HealthUniversity of AlbertaEdmontonABCanada
- Faculty of Kinesiology, Sport, and RecreationUniversity of AlbertaEdmontonABCanada
- Women and Children's Health Research Institute (WCHRI)University of AlbertaEdmontonABCanada
| | - Rshmi Khurana
- Women and Children's Health Research Institute (WCHRI)University of AlbertaEdmontonABCanada
- Departments of Medicine and Obstetrics and GynecologyFaculty of Medicine & DentistryUniversity of AlbertaEdmontonABCanada
| | - Charlotte W. Usselman
- Program for Pregnancy and Postpartum HealthUniversity of AlbertaEdmontonABCanada
- Women and Children's Health Research Institute (WCHRI)University of AlbertaEdmontonABCanada
| | - Stephen A. Busch
- Program for Pregnancy and Postpartum HealthUniversity of AlbertaEdmontonABCanada
- Faculty of Kinesiology, Sport, and RecreationUniversity of AlbertaEdmontonABCanada
| | - Rachel J. Skow
- Program for Pregnancy and Postpartum HealthUniversity of AlbertaEdmontonABCanada
- Faculty of Kinesiology, Sport, and RecreationUniversity of AlbertaEdmontonABCanada
- Women and Children's Health Research Institute (WCHRI)University of AlbertaEdmontonABCanada
| | - Normand G. Boulé
- Faculty of Kinesiology, Sport, and RecreationUniversity of AlbertaEdmontonABCanada
- Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - Margie H. Davenport
- Program for Pregnancy and Postpartum HealthUniversity of AlbertaEdmontonABCanada
- Faculty of Kinesiology, Sport, and RecreationUniversity of AlbertaEdmontonABCanada
- Women and Children's Health Research Institute (WCHRI)University of AlbertaEdmontonABCanada
- Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - Craig D. Steinback
- Program for Pregnancy and Postpartum HealthUniversity of AlbertaEdmontonABCanada
- Faculty of Kinesiology, Sport, and RecreationUniversity of AlbertaEdmontonABCanada
- Women and Children's Health Research Institute (WCHRI)University of AlbertaEdmontonABCanada
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Abstract
Obesity increases sympathetic nerve activity (SNA) in men, but not women. Here, we review current evidence suggesting that sexually dimorphic sympathoexcitatory responses to leptin and insulin may contribute. More specifically, while insulin increases SNA similarly in lean males and females, this response is markedly amplified in obese males, but is abolished in obese females. In lean female rats, leptin increases a subset of sympathetic nerves only during the high estrogen proestrus reproductive phase; thus, in obese females, because reproductive cycling can become impaired, the sporadic nature of leptin-induced sympathoexcitaton could minimize its action, despite elevated leptin levels. In contrast, in males, obesity preserves or enhances the central sympathoexcitatory response to leptin, and current evidence favors leptin’s contribution to the well-established increases in SNA induced by obesity in men. Leptin and insulin increase SNA via receptor binding in the hypothalamic arcuate nucleus and a neuropathway that includes arcuate neuropeptide Y (NPY) and proopiomelanocortin (POMC) projections to the paraventricular nucleus. These metabolic hormones normally suppress sympathoinhibitory NPY neurons and activate sympathoexcitatory POMC neurons. However, obesity appears to alter the ongoing activity and responsiveness of arcuate NPY and POMC neurons in a sexually dimorphic way, such that SNA increases in males but not females. We propose hypotheses to explain these sex differences and suggest areas of future research.
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Affiliation(s)
- Zhigang Shi
- Department of Physiology and Pharmacology, L-334, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, 97239, USA
| | - Jennifer Wong
- Department of Physiology and Pharmacology, L-334, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, 97239, USA
| | - Virginia L Brooks
- Department of Physiology and Pharmacology, L-334, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, 97239, USA.
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Brooks VL, Fu Q, Shi Z, Heesch CM. Adaptations in autonomic nervous system regulation in normal and hypertensive pregnancy. HANDBOOK OF CLINICAL NEUROLOGY 2020; 171:57-84. [PMID: 32736759 DOI: 10.1016/b978-0-444-64239-4.00003-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
There is an increase in basal sympathetic nerve activity (SNA) during normal pregnancy; this counteracts profound primary vasodilation. However, pregnancy also impairs baroreflex control of heart rate and SNA, contributing to increased mortality secondary to peripartum hemorrhage. Pregnancy-induced hypertensive disorders evoke even greater elevations in SNA, which likely contribute to the hypertension. Information concerning mechanisms is limited. In normal pregnancy, increased angiotensin II acts centrally to support elevated SNA. Hypothalamic sites, including the subfornical organ, paraventricular nucleus, and arcuate nucleus, are likely (but unproven) targets. Moreover, no definitive mechanisms for exaggerated sympathoexcitation in hypertensive pregnancy have been identified. In addition, normal pregnancy increases gamma aminobutyric acid inhibition of the rostral ventrolateral medulla (RVLM), a key brainstem site that transmits excitatory inputs to spinal sympathetic preganglionic neurons. Accumulated evidence supports a major role for locally increased production and actions of the neurosteroid allopregnanolone as one mechanism. A consequence is suppression of baroreflex function, but increased basal SNA indicates that excitatory influences predominate in the RVLM. However, many questions remain regarding other sites and factors that support increased SNA during normal pregnancy and, more importantly, the mechanisms underlying excessive sympathoexcitation in life-threatening hypertensive pregnancy disorders such as preeclampsia.
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Affiliation(s)
- Virginia L Brooks
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR, United States.
| | - Qi Fu
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, United States; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Zhigang Shi
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR, United States
| | - Cheryl M Heesch
- Department of Biomedical Sciences and Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, United States
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Spradley FT, Palei AC, Anderson CD, Granger JP. Melanocortin-4 Receptor Deficiency Attenuates Placental Ischemia-Induced Hypertension in Pregnant Rats. Hypertension 2019; 73:162-170. [PMID: 30571561 DOI: 10.1161/hypertensionaha.118.12028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Preeclampsia is a pregnancy-specific disorder of new-onset hypertension linked to placental ischemia. While obesity is a major risk factor for preeclampsia, not all obese pregnant women develop pregnancy-induced hypertension or preeclampsia. Previously, we reported that placental ischemia-induced hypertension is dependent upon intact signaling of the sympathetic nervous system. Moreover, in various models of obesity, blockade of MC4R (melanocortin-4 receptor) signaling protects against the development of hypertension via suppression of the sympathetic nervous system. Less is known about this pathway during obese pregnancy. Although blockade of MC4R may lead to increased body weight during pregnancy, we tested the hypothesis that placental ischemia-induced hypertension is attenuated in obese MC4R-deficient pregnant rats. On gestational day 14, MC4R wild-type or heterozygous-deficient (MC4R-def) rats were subjected to chronic placental ischemia via the reduced uterine perfusion pressure procedure or Sham surgery then examined on gestational day 19. In Sham MC4R-def versus Sham wild-type pregnant rats, there was increased body weight, fat mass, and circulating leptin levels but they had similar fetus weights. Reduced uterine perfusion pressure reduced fetus weights in both strains. Reduced uterine perfusion pressure increased blood pressure in wild-type rats but this response was significantly attenuated in MC4R-def rats, although blood pressure was elevated in Sham MC4R-def over Sham wild-type. These data indicate that while obese MC4R-def pregnant rats have higher blood pressure during pregnancy, placental ischemia-induced hypertension is attenuated in obese MC4R-def pregnant rats. Thus, obese women with abnormal MC4R signaling may be less susceptible to the development of placental ischemia-induced hypertension.
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Affiliation(s)
- Frank T Spradley
- From the Department of Surgery (F.T.S., A.C.P., C.D.A.), The University of Mississippi Medical Center, Jackson.,Department of Physiology and Biophysics (F.T.S., J.P.G.), The University of Mississippi Medical Center, Jackson
| | - Ana C Palei
- From the Department of Surgery (F.T.S., A.C.P., C.D.A.), The University of Mississippi Medical Center, Jackson
| | - Christopher D Anderson
- From the Department of Surgery (F.T.S., A.C.P., C.D.A.), The University of Mississippi Medical Center, Jackson
| | - Joey P Granger
- Department of Physiology and Biophysics (F.T.S., J.P.G.), The University of Mississippi Medical Center, Jackson
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Shi Z, Hansen KM, Bullock KM, Morofuji Y, Banks WA, Brooks VL. Resistance to the sympathoexcitatory effects of insulin and leptin in late pregnant rats. J Physiol 2019; 597:4087-4100. [PMID: 31209877 DOI: 10.1113/jp278282] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 06/10/2019] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Pregnancy increases sympathetic nerve activity (SNA), although the mechanisms responsible for this remain unknown. We tested whether insulin or leptin, two sympathoexcitatory hormones increased during pregnancy, contribute to this. Transport of insulin across the blood-brain barrier in some brain regions, and into the cerebrospinal fluid (CSF), was increased, although brain insulin degradation was also increased. As a result, brain and CSF insulin levels were not different between pregnant and non-pregnant rats. The sympathoexcitatory responses to insulin and leptin were abolished in pregnant rats. Blockade of arcuate nucleus insulin receptors did not lower SNA in pregnant or non-pregnant rats. Collectively, these data suggest that pregnancy renders the brain resistant to the sympathoexcitatory effects of insulin and leptin, and that these hormones do not mediate pregnancy-induced sympathoexcitation. Increased muscle SNA stimulates glucose uptake. Therefore, during pregnancy, peripheral insulin resistance coupled with blunted insulin- and leptin-induced sympathoexcitation ensures adequate delivery of glucose to the fetus. ABSTRACT Pregnancy increases basal sympathetic nerve activity (SNA), although the mechanism responsible for this remains unknown. Insulin and leptin are two sympathoexcitatory hormones that increase during pregnancy, yet, pregnancy impairs central insulin- and leptin-induced signalling. Therefore, to test whether insulin or leptin contribute to basal sympathoexcitation or, instead, whether pregnancy induces resistance to the sympathoexcitatory effects of insulin and leptin, we investigated α-chloralose anaesthetized late pregnant rats, which exhibited increases in lumbar SNA (LSNA), splanchnic SNA and heart rate (HR) compared to non-pregnant animals. In pregnant rats, transport of insulin into cerebrospinal fluid and across the blood-brain barrier in some brain regions increased, although brain insulin degradation was also increased; brain and cerebrospinal fluid insulin levels were not different between pregnant and non-pregnant rats. Although i.c.v. insulin increased LSNA and HR and baroreflex control of LSNA and HR in non-pregnant rats, these effects were abolished in pregnant rats. In parallel, pregnancy completely prevented the actions of leptin with respect to increasing lumbar, splanchnic and renal SNA, as well as baroreflex control of SNA. Blockade of insulin receptors (with S961) in the arcuate nucleus, the site of action of insulin, did not decrease LSNA in pregnant rats, despite blocking the effects of exogenous insulin. Thus, pregnancy is associated with central resistance to insulin and leptin, and these hormones are not responsible for the increased basal SNA of pregnancy. Because increases in LSNA to skeletal muscle stimulates glucose uptake, blunted insulin- and leptin-induced sympathoexcitation reinforces systemic insulin resistance, thereby increasing the delivery of glucose to the fetus.
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Affiliation(s)
- Zhigang Shi
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR, USA
| | - Kim M Hansen
- Geriatrics Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA
| | - Kristin M Bullock
- Geriatrics Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA
| | - Yoichi Morofuji
- Geriatrics Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA
| | - William A Banks
- Geriatrics Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA
| | - Virginia L Brooks
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR, USA
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Spradley FT. Sympathetic nervous system control of vascular function and blood pressure during pregnancy and preeclampsia. J Hypertens 2019; 37:476-487. [PMID: 30160658 PMCID: PMC6355368 DOI: 10.1097/hjh.0000000000001901] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
: Proper vascular tone and blood pressure regulation during pregnancy are important for immediate and long-term cardiovascular health of the mother and her offspring. Preeclampsia is clinically defined as new-onset maternal hypertension accompanied by cardiovascular, renal, and/or neural abnormalities presenting in the second half of pregnancy. There is strong evidence to support that preeclampsia is mediated by attenuations in uteroplacental vascular remodeling and increases in vasoconstriction with subsequent placental ischemia/reperfusion-induced release of hypertensive substances into the maternal circulation. These include antiangiogenic and pro-inflammatory factors. There is also evidence implicating increased sympathetic nervous system activity (SNA) in this maternal disorder, but this mostly includes data correlating severity of disease with catecholamine levels and elevated muscle SNA. These measurements have not confirmed a causative role for SNA in the pathogenesis of preeclampsia. Therefore, studies are needed to provide a comprehensive understanding of SNA and its control of vascular function and blood pressure regulation during normal pregnancy in order to set the stage for exploring the mechanisms mediating the exaggerated SNA and signaling during preeclampsia. This review examines the role of SNA in control of uteroplacental vascular tone and blood pressure regulation during normal pregnancy. Furthermore, it is proposed that over-activation of the SNA contributes to altered uteroplacental vascular tone and perfusion leading to placental ischemic events and modulates the systemic vasoconstriction and hypertensive responses to soluble placenta ischemic factors. Recognizing the integrative role and importance of SNA in the pathophysiology of preeclampsia will advance our understanding of this maternal disorder.
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Affiliation(s)
- Frank T Spradley
- Department of Surgery, The University of Mississippi Medical Center, Jackson, Mississippi, USA
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14
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Dampney RA, Michelini LC, Li DP, Pan HL. Regulation of sympathetic vasomotor activity by the hypothalamic paraventricular nucleus in normotensive and hypertensive states. Am J Physiol Heart Circ Physiol 2018; 315:H1200-H1214. [PMID: 30095973 PMCID: PMC6297824 DOI: 10.1152/ajpheart.00216.2018] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 07/13/2018] [Accepted: 07/25/2018] [Indexed: 12/22/2022]
Abstract
The hypothalamic paraventricular nucleus (PVN) is a unique and important brain region involved in the control of cardiovascular, neuroendocrine, and other physiological functions pertinent to homeostasis. The PVN is a major source of excitatory drive to the spinal sympathetic outflow via both direct and indirect projections. In this review, we discuss the role of the PVN in the regulation of sympathetic output in normal physiological conditions and in hypertension. In normal healthy animals, the PVN presympathetic neurons do not appear to have a major role in sustaining resting sympathetic vasomotor activity or in regulating sympathetic responses to short-term homeostatic challenges such as acute hypotension or hypoxia. Their role is, however, much more significant during longer-term challenges, such as sustained water deprivation, chronic intermittent hypoxia, and pregnancy. The PVN also appears to have a major role in generating the increased sympathetic vasomotor activity that is characteristic of multiple forms of hypertension. Recent studies in the spontaneously hypertensive rat model have shown that impaired inhibitory and enhanced excitatory synaptic inputs to PVN presympathetic neurons are the basis for the heightened sympathetic outflow in hypertension. We discuss the molecular mechanisms underlying the presynaptic and postsynaptic alterations in GABAergic and glutamatergic inputs to PVN presympathetic neurons in hypertension. In addition, we discuss the ability of exercise training to correct sympathetic hyperactivity by restoring blood-brain barrier integrity, reducing angiotensin II availability, and decreasing oxidative stress and inflammation in the PVN.
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Affiliation(s)
- Roger A Dampney
- Department of Physiology, University of Sydney , Sydney, New South Wales , Australia
| | - Lisete C Michelini
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo , São Paulo , Brazil
| | - De-Pei Li
- Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center , Houston, Texas
| | - Hui-Lin Pan
- Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center , Houston, Texas
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15
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Spradley FT, Ge Y, Haynes BP, Granger JP, Anderson CD. Adrenergic receptor blockade attenuates placental ischemia-induced hypertension. Physiol Rep 2018; 6:e13814. [PMID: 30229567 PMCID: PMC6121121 DOI: 10.14814/phy2.13814] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 07/07/2018] [Indexed: 12/15/2022] Open
Abstract
Preeclampsia (PE), a disorder of new-onset maternal hypertension and vascular dysfunction during pregnancy, is thought to be linked to placental ischemia-induced release of prohypertensive factors and reductions of vasoprotective factors in the maternal circulation. Although markers of sympathetic nervous activity are elevated in experimental models of placental ischemia-induced hypertension and women with PE compared with their normal pregnant counterparts, the importance of adrenergic receptor signaling in the development of hypertension in PE is unknown. Therefore, we tested the hypothesis that adrenergic receptor blockade attenuates the development of placental ischemia-induced hypertension in rats. Wistar Hannover rats underwent reduced uterine perfusion pressure (RUPP) or Sham surgeries on gestational day 14. By day 19, mean arterial blood pressure (MAP) was increased in RUPP over Sham rats. Groups of RUPP and Sham pregnant rats received terazosin and propranolol (3 mg/kg per day of each via subcutaneous osmotic minipump) to block α1- and β-adrenergic receptors, respectively, beginning on gestational day 14. Adrenergic blockade significantly attenuated the development of hypertension in the RUPP rats with a slight blood pressure-lowering response in the Sham, normal pregnant rats by day 19. In conclusion, these data implicate that placental ischemia-induced hypertension involves adrenergic receptor signaling to promote increases in blood pressure during PE.
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Affiliation(s)
- Frank T. Spradley
- Department of SurgeryThe University of Mississippi Medical CenterJacksonMississippi
- Department of Physiology & BiophysicsThe University of Mississippi Medical CenterJacksonMississippi
- Cardiovascular‐Renal Research CenterThe University of Mississippi Medical CenterJacksonMississippi
- Women's Health Research CenterThe University of Mississippi Medical CenterJacksonMississippi
| | - Ying Ge
- Department of SurgeryThe University of Mississippi Medical CenterJacksonMississippi
| | - B. Peyton Haynes
- Department of SurgeryThe University of Mississippi Medical CenterJacksonMississippi
| | - Joey P. Granger
- Department of Physiology & BiophysicsThe University of Mississippi Medical CenterJacksonMississippi
- Cardiovascular‐Renal Research CenterThe University of Mississippi Medical CenterJacksonMississippi
- Women's Health Research CenterThe University of Mississippi Medical CenterJacksonMississippi
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Reyes LM, Usselman CW, Davenport MH, Steinback CD. Sympathetic Nervous System Regulation in Human Normotensive and Hypertensive Pregnancies. Hypertension 2018. [DOI: 10.1161/hypertensionaha.117.10766] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Laura M. Reyes
- From the Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport and Recreation, Women and Children’s Health Research Institute (L.M.R., C.W.U., M.H.D., C.D.S.) and Alberta Diabetes Institute (M.H.D.), University of Alberta, Edmonton, Canada
| | - Charlotte W. Usselman
- From the Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport and Recreation, Women and Children’s Health Research Institute (L.M.R., C.W.U., M.H.D., C.D.S.) and Alberta Diabetes Institute (M.H.D.), University of Alberta, Edmonton, Canada
| | - Margie H. Davenport
- From the Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport and Recreation, Women and Children’s Health Research Institute (L.M.R., C.W.U., M.H.D., C.D.S.) and Alberta Diabetes Institute (M.H.D.), University of Alberta, Edmonton, Canada
| | - Craig D. Steinback
- From the Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport and Recreation, Women and Children’s Health Research Institute (L.M.R., C.W.U., M.H.D., C.D.S.) and Alberta Diabetes Institute (M.H.D.), University of Alberta, Edmonton, Canada
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17
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Hypothalamic dysfunction in heart failure: pathogenetic mechanisms and therapeutic implications. Heart Fail Rev 2017; 23:55-61. [DOI: 10.1007/s10741-017-9659-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Shi Z, Madden CJ, Brooks VL. Arcuate neuropeptide Y inhibits sympathetic nerve activity via multiple neuropathways. J Clin Invest 2017. [PMID: 28628036 PMCID: PMC5490747 DOI: 10.1172/jci92008] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Obesity increases sympathetic nerve activity (SNA) via activation of proopiomelanocortin neurons in the arcuate nucleus (ArcN), and this action requires simultaneous withdrawal of tonic neuropeptide Y (NPY) sympathoinhibition. However, the sites and neurocircuitry by which NPY decreases SNA are unclear. Here, using designer receptors exclusively activated by designer drugs (DREADDs) to selectively activate or inhibit ArcN NPY neurons expressing agouti-related peptide (AgRP) in mice, we have demonstrated that this neuronal population tonically suppresses splanchnic SNA (SSNA), arterial pressure, and heart rate via projections to the paraventricular nucleus (PVN) and dorsomedial hypothalamus (DMH). First, we found that ArcN NPY/AgRP fibers closely appose PVN and DMH presympathetic neurons. Second, nanoinjections of NPY or an NPY receptor Y1 (NPY1R) antagonist into PVN or DMH decreased or increased SSNA, respectively. Third, blockade of DMH NPY1R reversed the sympathoinhibition elicited by selective, DREADD-mediated activation of ArcN NPY/AgRP neurons. Finally, stimulation of ArcN NPY/AgRP terminal fields in the PVN and DMH decreased SSNA. Considering that chronic obesity decreases ArcN NPY content, we propose that the ArcN NPY neuropathway to the PVN and DMH is pivotal in obesity-induced elevations in SNA.
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Affiliation(s)
- Zhigang Shi
- Department of Physiology and Pharmacology and
| | - Christopher J Madden
- Department of Neurological Surgery, Oregon Health & Science University, Portland, Oregon, USA
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Rahmouni K. Cardiovascular Regulation by the Arcuate Nucleus of the Hypothalamus: Neurocircuitry and Signaling Systems. Hypertension 2016; 67:1064-71. [PMID: 27045026 PMCID: PMC4865428 DOI: 10.1161/hypertensionaha.115.06425] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Kamal Rahmouni
- From the Department of Pharmacology and Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City.
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20
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Cassaglia PA, Shi Z, Brooks VL. Insulin increases sympathetic nerve activity in part by suppression of tonic inhibitory neuropeptide Y inputs into the paraventricular nucleus in female rats. Am J Physiol Regul Integr Comp Physiol 2016; 311:R97-R103. [PMID: 27122366 PMCID: PMC4967227 DOI: 10.1152/ajpregu.00054.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 04/26/2016] [Indexed: 11/22/2022]
Abstract
Following binding to receptors in the arcuate nucleus (ArcN), insulin increases sympathetic nerve activity (SNA) and baroreflex control of SNA via a pathway that includes the paraventricular nucleus of the hypothalamus (PVN). Previous studies in males indicate that the sympathoexcitatory response is mediated by α-melanocyte stimulating hormone (α-MSH), which binds to PVN melanocortin type 3/4 receptors (MC3/4R). The present study was conducted in α-chloralose-anesthetized female rats to test the hypothesis that suppression of inhibitory neuropeptide Y (NPY) inputs to the PVN is also involved. In support of this, blockade of PVN NPY Y1 receptors with BIBO 3304 (NPY1x), ArcN insulin nanoinjections, and PVN NPY1x followed by ArcN insulin each increased lumbar SNA (LSNA) and its baroreflex regulation similarly. Moreover, prior PVN injections of NPY blocked the sympathoexcitatory effects of ArcN insulin. Finally, PVN nanoinjections of the MC3/4R inhibitor SHU9119 prevented both the acute (15 min) and longer, more slowly developing (60 min), increases in LSNA in response to ArcN insulin. In conclusion, in females, ArcN insulin increases LSNA, in part, by suppressing tonic PVN NPY inhibition, which unmasks excitatory α-MSH drive of LSNA. Moreover, the steadily increasing rise in LSNA induced by ArcN insulin is also dependent on PVN MC3/4R.
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Affiliation(s)
- Priscila A Cassaglia
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon
| | - Zhigang Shi
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon
| | - Virginia L Brooks
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon
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