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Pace SA, Lukinic E, Wallace T, McCartney C, Myers B. Cortical-brainstem circuitry attenuates physiological stress reactivity. J Physiol 2024; 602:949-966. [PMID: 38353989 PMCID: PMC10940195 DOI: 10.1113/jp285627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 01/24/2024] [Indexed: 02/27/2024] Open
Abstract
Exposure to stressful stimuli promotes multi-system biological responses to restore homeostasis. Catecholaminergic neurons in the rostral ventrolateral medulla (RVLM) facilitate sympathetic activity and promote physiological adaptations, including glycaemic mobilization and corticosterone release. While it is unclear how brain regions involved in the cognitive appraisal of stress regulate RVLM neural activity, recent studies found that the rodent ventromedial prefrontal cortex (vmPFC) mediates stress appraisal and physiological stress responses. Thus, a vmPFC-RVLM connection could represent a circuit mechanism linking stress appraisal and physiological reactivity. The current study investigated a direct vmPFC-RVLM circuit utilizing genetically encoded anterograde and retrograde tract tracers. Together, these studies found that stress-activated vmPFC neurons project to catecholaminergic neurons throughout the ventrolateral medulla in male and female rats. Next, we utilized optogenetic terminal stimulation to evoke vmPFC synaptic glutamate release in the RVLM. Photostimulating the vmPFC-RVLM circuit during restraint stress suppressed glycaemic stress responses in males, without altering the female response. However, circuit stimulation decreased corticosterone responses to stress in both sexes. Circuit stimulation did not modulate affective behaviour in either sex. Further analysis indicated that circuit stimulation preferentially activated non-catecholaminergic medullary neurons in both sexes. Additionally, vmPFC terminals targeted medullary inhibitory neurons. Thus, both male and female rats have a direct vmPFC projection to the RVLM that reduces endocrine stress responses, likely by recruiting local RVLM inhibitory neurons. Ultimately, the excitatory/inhibitory balance of vmPFC synapses in the RVLM may regulate stress reactivity and stress-related health outcomes. KEY POINTS: Glutamatergic efferents from the ventromedial prefrontal cortex target catecholaminergic neurons throughout the ventrolateral medulla. Partially segregated, stress-activated ventromedial prefrontal cortex populations innervate the rostral and caudal ventrolateral medulla. Stimulating ventromedial prefrontal cortex synapses in the rostral ventrolateral medulla decreases stress-induced glucocorticoid release in males and females. Stimulating ventromedial prefrontal cortex terminals in the rostral ventrolateral medulla preferentially activates non-catecholaminergic neurons. Ventromedial prefrontal cortex terminals target medullary inhibitory neurons.
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Affiliation(s)
- Sebastian A. Pace
- Biomedical Sciences, Colorado State University, Fort Collins, CO, USA 80523
| | - Ema Lukinic
- Biomedical Sciences, Colorado State University, Fort Collins, CO, USA 80523
| | - Tyler Wallace
- Biomedical Sciences, Colorado State University, Fort Collins, CO, USA 80523
| | - Carlie McCartney
- Biomedical Sciences, Colorado State University, Fort Collins, CO, USA 80523
| | - Brent Myers
- Biomedical Sciences, Colorado State University, Fort Collins, CO, USA 80523
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Pace SA, Myers B. Hindbrain Adrenergic/Noradrenergic Control of Integrated Endocrine and Autonomic Stress Responses. Endocrinology 2023; 165:bqad178. [PMID: 38015813 DOI: 10.1210/endocr/bqad178] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 11/07/2023] [Accepted: 11/27/2023] [Indexed: 11/30/2023]
Abstract
Hindbrain adrenergic/noradrenergic nuclei facilitate endocrine and autonomic responses to physical and psychological challenges. Neurons that synthesize adrenaline and noradrenaline target hypothalamic structures to modulate endocrine responses while descending spinal projections regulate sympathetic function. Furthermore, these neurons respond to diverse stress-related metabolic, autonomic, and psychosocial challenges. Accordingly, adrenergic and noradrenergic nuclei are integrative hubs that promote physiological adaptation to maintain homeostasis. However, the precise mechanisms through which adrenaline- and noradrenaline-synthesizing neurons sense interoceptive and exteroceptive cues to coordinate physiological responses have yet to be fully elucidated. Additionally, the regulatory role of these cells in the context of chronic stress has received limited attention. This mini-review consolidates reports from preclinical rodent studies on the organization and function of brainstem adrenaline and noradrenaline cells to provide a framework for how these nuclei coordinate endocrine and autonomic physiology. This includes identification of hindbrain adrenaline- and noradrenaline-producing cell groups and their role in stress responding through neurosecretory and autonomic engagement. Although temporally and mechanistically distinct, the endocrine and autonomic stress axes are complementary and interconnected. Therefore, the interplay between brainstem adrenergic/noradrenergic nuclei and peripheral physiological systems is necessary for integrated stress responses and organismal survival.
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Affiliation(s)
- Sebastian A Pace
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Brent Myers
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
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Pace SA, Lukinic E, Wallace T, McCartney C, Myers B. Cortical-brainstem circuitry attenuates physiological stress reactivity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.19.549781. [PMID: 37502866 PMCID: PMC10370137 DOI: 10.1101/2023.07.19.549781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Exposure to stressful stimuli promotes multi-system biological responses to restore homeostasis. Catecholaminergic neurons in the rostral ventrolateral medulla (RVLM) facilitate sympathetic activity and promote physiological adaptations, including glycemic mobilization and corticosterone release. While it is unclear how brain regions involved in the cognitive appraisal of stress regulate RVLM neural activity, recent studies found that the rodent ventromedial prefrontal cortex (vmPFC) mediates stress appraisal and physiological stress responses. Thus, a vmPFC-RVLM connection could represent a circuit mechanism linking stress appraisal and physiological reactivity. The current study investigated a direct vmPFC-RVLM circuit utilizing genetically-encoded anterograde and retrograde tract tracers. Together, these studies found that stress-reactive vmPFC neurons project to catecholaminergic neurons throughout the ventrolateral medulla in male and female rats. Next, we utilized optogenetic terminal stimulation to evoke vmPFC synaptic glutamate release in the RVLM. Photostimulating the vmPFC-RVLM circuit during restraint stress suppressed glycemic stress responses in males, without altering the female response. However, circuit stimulation decreased corticosterone responses to stress in both sexes. Circuit stimulation did not modulate affective behavior in either sex. Further analysis indicated that circuit stimulation preferentially activated non-catecholaminergic medullary neurons in both sexes. Additionally, vmPFC terminals targeted medullary inhibitory neurons. Thus, both male and female rats have a direct vmPFC projection to the RVLM that reduces endocrine stress responses, likely through the recruitment of local RVLM inhibitory neurons. Ultimately, the excitatory/inhibitory balance of vmPFC synapses in the RVLM may regulate stress reactivity as well as stress-related health outcomes.
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Affiliation(s)
- Sebastian A. Pace
- Biomedical Sciences, Colorado State University, Fort Collins, CO, USA 80523
| | - Ema Lukinic
- Biomedical Sciences, Colorado State University, Fort Collins, CO, USA 80523
| | - Tyler Wallace
- Biomedical Sciences, Colorado State University, Fort Collins, CO, USA 80523
| | - Carlie McCartney
- Biomedical Sciences, Colorado State University, Fort Collins, CO, USA 80523
| | - Brent Myers
- Biomedical Sciences, Colorado State University, Fort Collins, CO, USA 80523
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Situmorang JH, Lin HH, Islam MS, Lai CC. Ovariectomy Exacerbates Acute Ethanol-Induced Tachycardia: Role of Nitric Oxide and NMDA Receptors in the Rostral Ventrolateral Medulla. Int J Mol Sci 2023; 24:5087. [PMID: 36982161 PMCID: PMC10049173 DOI: 10.3390/ijms24065087] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 03/04/2023] [Accepted: 03/05/2023] [Indexed: 03/09/2023] Open
Abstract
Ethanol consumption influences cardiovascular functions. In humans, acute consumption of ethanol causes dose-dependent tachycardia. Our previous study showed that ethanol-induced tachycardia might involve decreased nitric oxide (NO) signaling in the brain's medulla. NMDA receptors, another important target of ethanol, are one of the upstream signals of nitric oxide. Reports showed the modulation of NMDA receptor function by estrogen or estrogen receptors. The present study aims to examine the hypothesis that depletion of estrogen by ovariectomy (OVX) might modulate ethanol-induced tachycardia by regulating NMDA receptor function and NO signaling in the cardiovascular regulatory nucleus of the brain. Ethanol (3.2 g/kg, 40% v/v, 10 mL/kg) or saline (10 mL/kg) was administered by oral gavage in sham or OVX female Sprague-Dawley (SD) rats. The blood pressure (BP) and heart rate (HR) were measured using the tail-cuff method. The levels of phosphoserine 896 of the GluN1 subunit (pGluN1-serine 896) and NMDA GluN1 subunits (GluN1) were determined by immunohistochemistry. The expressions of nitric oxide synthase (NOS) and estrogen receptors in the tissue were measured by Western blotting. Nitric oxide contents were measured as total nitrate-nitrite by colorimetric assay kit. In a 2-h observation, there was no significant change in BP between the saline and ethanol groups. However, compared with saline, ethanol caused an increase in HR (tachycardia) in sham control or OVX rats. Interestingly, ethanol produced more significant tachycardia in the OVX group than in the sham control group. Nitric oxide levels were lower in the area of the rostral ventrolateral medulla (RVLM) 60 min following ethanol administration in OVX compared with sham control, without significant changes in the expression of NOS and estrogen receptors (ERα and ERβ). In addition, a decrease in the immunoreactivity of pGluN1-serine 896, without significant changes in GluN1, was found in neurons of RVLM 40 min following ethanol administration in OVX compared with sham control. Our results suggest that depletion of estradiol (E2) by OVX might exacerbate the tachycardia following ethanol administration, the underlying mechanism of which might be associated with decreased NMDA receptor function and NO level in the RVLM.
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Affiliation(s)
- Jiro Hasegawa Situmorang
- Master and PhD Programs in Pharmacology and Toxicology, School of Medicine, Tzu Chi University, Hualien 970374, Taiwan
- Center for Biomedical Research, National Research and Innovation Agency (BRIN), Cibinong 16915, Indonesia
| | - Hsun-Hsun Lin
- Department of Physiology, School of Medicine, Tzu Chi University, Hualien 970374, Taiwan
| | - Md Sharyful Islam
- Master and PhD Programs in Pharmacology and Toxicology, School of Medicine, Tzu Chi University, Hualien 970374, Taiwan
| | - Chih-Chia Lai
- Master and PhD Programs in Pharmacology and Toxicology, School of Medicine, Tzu Chi University, Hualien 970374, Taiwan
- Department of Pharmacology, School of Medicine, Tzu Chi University, Hualien 970374, Taiwan
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Wang M, Yang Y, Xu Y. Brain nuclear receptors and cardiovascular function. Cell Biosci 2023; 13:14. [PMID: 36670468 PMCID: PMC9854230 DOI: 10.1186/s13578-023-00962-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 01/12/2023] [Indexed: 01/22/2023] Open
Abstract
Brain-heart interaction has raised up increasing attentions. Nuclear receptors (NRs) are abundantly expressed in the brain, and emerging evidence indicates that a number of these brain NRs regulate multiple aspects of cardiovascular diseases (CVDs), including hypertension, heart failure, atherosclerosis, etc. In this review, we will elaborate recent findings that have established the physiological relevance of brain NRs in the context of cardiovascular function. In addition, we will discuss the currently available evidence regarding the distinct neuronal populations that respond to brain NRs in the cardiovascular control. These findings suggest connections between cardiac control and brain dynamics through NR signaling, which may lead to novel tools for the treatment of pathological changes in the CVDs.
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Affiliation(s)
- Mengjie Wang
- grid.508989.50000 0004 6410 7501Department of Pediatrics, USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX USA
| | - Yongjie Yang
- grid.508989.50000 0004 6410 7501Department of Pediatrics, USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX USA
| | - Yong Xu
- grid.508989.50000 0004 6410 7501Department of Pediatrics, USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX USA ,grid.39382.330000 0001 2160 926XDepartment of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX USA
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Maruyama NO, Estrela HF, Sales EBO, Lucas TF, Porto CS, Bergamaschi CT, Campos RR. Differential effects of estrogen receptors in the rostral ventrolateral medulla in Goldblatt hypertension. J Steroid Biochem Mol Biol 2022; 224:106176. [PMID: 36087695 DOI: 10.1016/j.jsbmb.2022.106176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 08/31/2022] [Accepted: 09/01/2022] [Indexed: 11/18/2022]
Abstract
Previous studies have shown that 17β-estradiol plays a cardioprotective role in the central nervous system (CNS) of male rats. The aim of the present study was to determine the influence of 17β-estradiol on sympathetic vasomotor activity and blood pressure in a renovascular hypertensive Goldblatt two-kidney one-clip (2K-1C) male rat model. We also determined the influence of angiotensin II AT1 receptor on the expression of estrogen receptors (ERα, ERβ, and G protein-coupled ER (GPER)) in the rostral ventrolateral medulla (RVLM) of Goldblatt rats. Experiments were performed in Goldblatt and age-matched control rats six weeks after clipping of renal artery to induce hypertension. Microinjection of 17β-estradiol into the RVLM led to a greater reduction in mean arterial pressure and renal sympathetic nerve activity in controls than in 2K-1C rats. Microinjection of the GPER agonist G-1 into the RVLM led to a significantly greater increase in mean arterial pressure and renal sympathetic nerve activity in 2K-1C rats. Expression levels of estrogen receptors GPER and ERα, but not ERβ, were significantly higher in the RVLM of 2K-1C rats than in that of the control rats. Chronic treatment with losartan significantly reduced the expression levels of estrogen receptors in the RVLM of 2K-1C rats. Taken altogether, the data suggest that the imbalance of actions between ERα and GPER, particularly with the predominance of GPER in the RVLM, contributes to sympathetic overactivation in male rats with Goldblatt hypertension. AT1-Angiotensin II receptor in the RVLM upregulated estrogen receptor expression in male Goldblatt rats.
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Affiliation(s)
- N O Maruyama
- Department of Physiology, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - H F Estrela
- Department of Physiology, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - E B Oliveira Sales
- Department of Physiology, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - T F Lucas
- Laboratory of Experimental Endocrinology, Department of Pharmacology, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - C S Porto
- Laboratory of Experimental Endocrinology, Department of Pharmacology, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - C T Bergamaschi
- Department of Physiology, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - R R Campos
- Department of Physiology, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil.
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Estrogen Dampens Central Cannabinoid Receptor 1-mediated Neuroexcitation and Pressor Response in Conscious Female Rats. Biochem Pharmacol 2022; 201:115102. [PMID: 35617998 DOI: 10.1016/j.bcp.2022.115102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/18/2022] [Accepted: 05/18/2022] [Indexed: 11/20/2022]
Abstract
Activation of the rostral ventrolateral medulla (RVLM) cannabinoid receptor-1 (CB1R) causes nNOS-dependent increases in sympathetic activity, blood pressure (BP) and heart rate (HR) in male rats. However, it remains unknown if the CB1R-mediated neurochemical and cardiovascular responses are influenced by the ovarian sex hormones, particularly estrogen (E2). Therefore, we studied the effects of intra-RVLM CB1R activation (WIN 55,212-2) on BP and HR in conscious female rats under the following hormonal states: (1) highest E2 level (proestrus sham-operated, SO); (2) E2-deprivation (ovariectomized, OVX); (3) OVX with E2 replacement (OVXE2). Intra-RVLM WIN55,212-2 elicited dose (100-400 pmol) dependent pressor and tachycardic responses, in OVX rats, which replicated the reported responses in male rats. However, in SO and OVXE2 rats, the CB1R-mediated pressor response was attenuated and the tachycardic response reverted to bradycardic response. The neurochemical findings suggested a key role for the upregulated RVLM sympathoexcitatory molecules phosphorated protein kinase B, phosphorated neuronal nitric oxide synthase and reactive oxygen species in the exaggerated CB1R-mediated BP and HR responses in OVX rats, and an E2-dependent dampening of these responses. The intra-RVLM WIN55212-2-evoked cardiovascular and neurochemical responses were CB1R-mediated because they were attenuated by prior CB1R blockade (AM251). Our findings suggest that attenuation of RVLM neuroexcitation and oxidative stress underlies the protection conferred by E2, in female rats, against the CB1R-mediated adverse cardiovascular effects.
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8
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Littlejohn EL, Fedorchak S, Boychuk CR. Sex-steroid-dependent plasticity of brain-stem autonomic circuits. Am J Physiol Regul Integr Comp Physiol 2020; 319:R60-R68. [PMID: 32493037 DOI: 10.1152/ajpregu.00357.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In the central nervous system (CNS), nuclei of the brain stem play a critical role in the integration of peripheral sensory information and the regulation of autonomic output in mammalian physiology. The nucleus tractus solitarius of the brain stem acts as a relay center that receives peripheral sensory input from vagal afferents of the nodose ganglia, integrates information from within the brain stem and higher central centers, and then transmits autonomic efferent output through downstream premotor nuclei, such as the nucleus ambiguus, the dorsal motor nucleus of the vagus, and the rostral ventral lateral medulla. Although there is mounting evidence that sex and sex hormones modulate autonomic physiology at the level of the CNS, the mechanisms and neurocircuitry involved in producing these functional consequences are poorly understood. Of particular interest in this review is the role of estrogen, progesterone, and 5α-reductase-dependent neurosteroid metabolites of progesterone (e.g., allopregnanolone) in the modulation of neurotransmission within brain-stem autonomic neurocircuits. This review will discuss our understanding of the actions and mechanisms of estrogen, progesterone, and neurosteroids at the cellular level of brain-stem nuclei. Understanding the complex interaction between sex hormones and neural signaling plasticity of the autonomic nervous system is essential to elucidating the role of sex in overall physiology and disease.
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Affiliation(s)
- Erica L Littlejohn
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, Texas
| | - Stephanie Fedorchak
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, Texas
| | - Carie R Boychuk
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, Texas
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Silva TLA, Braz GRF, Silva SCDA, Pedroza AADS, Freitas CDM, Ferreira DJS, da Silva AI, Lagranha CJ. Serotonin transporter inhibition during neonatal period induces sex-dependent effects on mitochondrial bioenergetics in the rat brainstem. Eur J Neurosci 2018; 48:1620-1634. [PMID: 29802653 DOI: 10.1111/ejn.13971] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 04/19/2018] [Accepted: 05/14/2018] [Indexed: 12/29/2022]
Abstract
The serotonin reuptake is mainly regulated by the serotonin transporters (SERTs), which are abundantly found in the raphe nuclei, located in the brainstem. Previous studies have shown that dysfunction in the SERT has been associated with several disorders, including depression and cardiovascular diseases. In this manuscript, we aimed to investigate how gender and the treatment with a serotonin selective reuptake inhibitor (SSRI) could affect mitochondrial bioenergetics and oxidative stress in the brainstem of male and female rats. Fluoxetine, our chosen SSRI, was used during the neonatal period (i.e., from postnatal Day 1 to postnatal Day 21-PND1 to PND21) in both male and female animals. Thereafter, experiments were conducted in adult rats (60 days old). Our results demonstrate that, during lactation, fluoxetine treatment modulates the mitochondrial bioenergetics in a sex-dependent manner, such as improving male mitochondrial function and female antioxidant capacity.
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Affiliation(s)
- Tercya Lucidi Araujo Silva
- Neuropsychiatry and Behavioral Science Graduate Program, Federal University of Pernambuco, Recife, Brazil
| | - Glauber Rudá Feitoza Braz
- Neuropsychiatry and Behavioral Science Graduate Program, Federal University of Pernambuco, Recife, Brazil
| | | | | | | | | | - Aline Isabel da Silva
- Neuropsychiatry and Behavioral Science Graduate Program, Federal University of Pernambuco, Recife, Brazil
| | - Claudia Jacques Lagranha
- Neuropsychiatry and Behavioral Science Graduate Program, Federal University of Pernambuco, Recife, Brazil
- Biochemistry and Physiology Graduate Program, Federal University of Pernambuco, Recife, Brazil
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Lagranha CJ, Silva TLA, Silva SCA, Braz GRF, da Silva AI, Fernandes MP, Sellitti DF. Protective effects of estrogen against cardiovascular disease mediated via oxidative stress in the brain. Life Sci 2017; 192:190-198. [PMID: 29191645 DOI: 10.1016/j.lfs.2017.11.043] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 11/07/2017] [Accepted: 11/26/2017] [Indexed: 01/27/2023]
Abstract
During their reproductive years women produce significant levels of estrogens, predominantly in the form of estradiol, that are thought to play an important role in cardioprotection. Mechanisms underlying this action include both estrogen-mediated changes in gene expression, and post-transcriptional activation of protein signaling cascades in the heart and in neural centers controlling cardiovascular function, in particular, in the brainstem. There, specific neurons, especially those of the bulbar region play an important role in the neuronal control of the cardiovascular system because they control the outflow of sympathetic activity and parasympathetic activity as well as the reception of chemical and mechanical signals. In the present review, we discuss how estrogens exert their cardioprotective effect in part by modulating the actions of internally generated products of cellular oxidation such as reactive oxygen species (ROS) in brain stem neurons. The significance of this review is in integrating the literature of oxidative damage in the brain with the literature of neuroprotection by estrogen in order to better understand both the benefits and limitations of using this hormone to prevent cardiovascular disease.
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Affiliation(s)
- Claudia J Lagranha
- Neuropsychiatry and Behavior Science Graduate Program, Federal University of Pernambuco, 50670-901, Brazil; Laboratory of Biochemistry and Exercise Biochemistry, Department of Physical Education and Sports Science, Federal University of Pernambuco-CAV, Vitória de Santo Antão 55608-680, Brazil.
| | - Tercya Lucidi Araujo Silva
- Neuropsychiatry and Behavior Science Graduate Program, Federal University of Pernambuco, 50670-901, Brazil; Laboratory of Biochemistry and Exercise Biochemistry, Department of Physical Education and Sports Science, Federal University of Pernambuco-CAV, Vitória de Santo Antão 55608-680, Brazil
| | - Severina Cassia A Silva
- Laboratory of Biochemistry and Exercise Biochemistry, Department of Physical Education and Sports Science, Federal University of Pernambuco-CAV, Vitória de Santo Antão 55608-680, Brazil
| | - Glaber Ruda F Braz
- Laboratory of Biochemistry and Exercise Biochemistry, Department of Physical Education and Sports Science, Federal University of Pernambuco-CAV, Vitória de Santo Antão 55608-680, Brazil
| | - Aline Isabel da Silva
- Neuropsychiatry and Behavior Science Graduate Program, Federal University of Pernambuco, 50670-901, Brazil; Laboratory of Biochemistry and Exercise Biochemistry, Department of Physical Education and Sports Science, Federal University of Pernambuco-CAV, Vitória de Santo Antão 55608-680, Brazil
| | - Mariana Pinheiro Fernandes
- Laboratory of Biochemistry and Exercise Biochemistry, Department of Physical Education and Sports Science, Federal University of Pernambuco-CAV, Vitória de Santo Antão 55608-680, Brazil
| | - Donald F Sellitti
- Department of Anatomy, Physiology, and Genetics, School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
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Boese AC, Kim SC, Yin KJ, Lee JP, Hamblin MH. Sex differences in vascular physiology and pathophysiology: estrogen and androgen signaling in health and disease. Am J Physiol Heart Circ Physiol 2017. [PMID: 28626075 DOI: 10.1152/ajpheart.00217.2016] [Citation(s) in RCA: 129] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sex differences between women and men are often overlooked and underappreciated when studying the cardiovascular system. It has been long assumed that men and women are physiologically similar, and this notion has resulted in women being clinically evaluated and treated for cardiovascular pathophysiological complications as men. Currently, there is increased recognition of fundamental sex differences in cardiovascular function, anatomy, cell signaling, and pathophysiology. The National Institutes of Health have enacted guidelines expressly to gain knowledge about ways the sexes differ in both normal function and diseases at the various research levels (molecular, cellular, tissue, and organ system). Greater understanding of these sex differences will be used to steer future directions in the biomedical sciences and translational and clinical research. This review describes sex-based differences in the physiology and pathophysiology of the vasculature, with a special emphasis on sex steroid receptor (estrogen and androgen receptor) signaling and their potential impact on vascular function in health and diseases (e.g., atherosclerosis, hypertension, peripheral artery disease, abdominal aortic aneurysms, cerebral aneurysms, and stroke).
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Affiliation(s)
- Austin C Boese
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Seong C Kim
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Ke-Jie Yin
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Jean-Pyo Lee
- Department of Neurology, Tulane University School of Medicine, New Orleans, Louisiana; and.,Center for Stem Cell Research and Regenerative Medicine, New Orleans, Louisiana
| | - Milton H Hamblin
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana;
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12
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Özdemir Kumral ZN, Kolgazi M, Üstünova S, Kasımay Çakır Ö, Çevik ÖD, Şener G, Yeğen BÇ. Estrogen receptor agonists alleviate cardiac and renal oxidative injury in rats with renovascular hypertension. Clin Exp Hypertens 2016; 38:500-9. [DOI: 10.3109/10641963.2015.1116550] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
| | - Meltem Kolgazi
- Acibadem University School of Medicine, Department of Physiology, Istanbul, Turkey
| | - Savaş Üstünova
- Bezmialem Vakıf University School of Medicine, Department of Physiology, Istanbul, Turkey
| | - Özgür Kasımay Çakır
- Marmara University School of Medicine, Department of Physiology, Istanbul, Turkey
| | - Özge Dağdeviren Çevik
- Cumhuriyet University Faculty of Pharmacy, Department of Biochemistry, Sivas, Turkey
| | - Göksel Şener
- Marmara University Faculty of Pharmacy, Department of Pharmacology, Istanbul, Turkey
| | - Berrak Ç. Yeğen
- Marmara University School of Medicine, Department of Physiology, Istanbul, Turkey
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13
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Kafami M, Hosseini M, Niazmand S, Hadjzadeh MA, Farrokhi E, Mazloum T, Shafei MN. Interaction of central Angiotensin II and estrogen on systolic blood pressure in female DOCA-salt treated rats. Adv Biomed Res 2016; 5:78. [PMID: 27195251 PMCID: PMC4863408 DOI: 10.4103/2277-9175.180990] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 07/14/2014] [Indexed: 02/07/2023] Open
Abstract
Background: There is a probable interaction of central angiotensin II (Ang II) and estrogen (Est) on blood pressure in deoxycorticosterone acetate (DOCA)-salt hypertensive rats. Therefore, in the present study, the interaction between Ang II and Est in ovariectomized (Ovx) and Sham rats that were treated with DOCA- salt was evaluated. Materials and Methods: The female rats were divided into 10 groups as follows: Sham, Ovx, Sham-DOCA, Ovx-DOCA, Sham-DOCA-estrogen (E), Ovx DOCA-E, Sham-DOCA-losartan (L), Ovx-DOCA-L, Sham–DOCA-L-E, and Ovx-DOCA-L-E. The Est groups received estradiol valerate (2 mg/kg; daily; subcutaneously (s.c)) for four weeks. Following that, several doses of Ang II (0.5, 5, 50, 500, 5000 ng/5 μl) were injected via the intracerebroventricular (i.c.v) route and the changes in systolic blood pressure (SBP) were evaluated. In the losartan groups, 200 μg losartan was injected (i.c.v) 15 minutes after the Ang II injection and the blood pressure was recorded. Treatment by DOCA was performed by removal of one kidney, injection of DOCA (45 mg/kg i.p), and adding of sodium chloride (NaCl) (1%) and potassium chloride (KCl) (0.1%) in the drinking water. Results: The SBP was increased by Ang II and this effect in DOCA-salt treated rat was higher than in the untreated groups. The effect of Ang II on SBP in groups that were treated with Est and L was lower than that in the DOCA-salt groups. Increase in SBP was strongly attenuated by Ang II in groups that were co-treated with both Est and L compared to the DOCA-treated rats. These results showed that Est significantly attenuated the effect of central Ang II on SBP in the DOCA-salt treated rats. Conclusion: We suggest that there are interactions between E and Ang II in the control of blood pressure in DOCA-salt treated rats.
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Affiliation(s)
- Marzieh Kafami
- Department of Physiology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mahmoud Hosseini
- Neurocognetive Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Saeed Niazmand
- Department of Physiology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mousa Alreza Hadjzadeh
- Department of Physiology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran; Neurocognetive Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Esmaeil Farrokhi
- Department of Physiology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Tahereh Mazloum
- Neurocognetive Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad Naser Shafei
- Neurogenic Inflammation Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
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14
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Abstract
The central nervous system (CNS) in concert with the heart and vasculature is essential to maintaining cardiovascular (CV) homeostasis. In recent years, our understanding of CNS control of blood pressure regulation (and dysregulation leading to hypertension) has evolved substantially to include (i) the actions of signaling molecules that are not classically viewed as CV signaling molecules, some of which exert effects at CNS targets in a non-traditional manner, and (ii) CNS locations not traditionally viewed as central autonomic cardiovascular centers. This review summarizes recent work implicating immune signals and reproductive hormones, as well as gasotransmitters and reactive oxygen species in the pathogenesis of hypertension at traditional CV control centers. Additionally, recent work implicating non-conventional CNS structures in CV regulation is discussed.
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Affiliation(s)
- Pauline M Smith
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, K7L3N6, Canada
| | - Alastair V Ferguson
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, K7L3N6, Canada
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15
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Sex, the brain and hypertension: brain oestrogen receptors and high blood pressure risk factors. Clin Sci (Lond) 2015; 130:9-18. [DOI: 10.1042/cs20150654] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Hypertension is a major contributor to worldwide morbidity and mortality rates related to cardiovascular disease. There are important sex differences in the onset and rate of hypertension in humans. Compared with age-matched men, premenopausal women are less likely to develop hypertension. However, after age 60, the incidence of hypertension increases in women and even surpasses that seen in older men. It is thought that changes in levels of circulating ovarian hormones as women age may be involved in the increase in hypertension in older women. One of the key mechanisms involved in the development of hypertension in both men and women is an increase in sympathetic nerve activity (SNA). Brain regions important for the regulation of SNA, such as the subfornical organ, the paraventricular nucleus and the rostral ventral lateral medulla, also express specific subtypes of oestrogen receptors. Each of these brain regions has also been implicated in mechanisms underlying risk factors for hypertension such as obesity, stress and inflammation. The present review brings together evidence that links actions of oestrogen at these receptors to modulate some of the common brain mechanisms involved in the ability of hypertensive risk factors to increase SNA and blood pressure. Understanding the mechanisms by which oestrogen acts at key sites in the brain for the regulation of SNA is important for the development of novel, sex-specific therapies for treating hypertension.
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16
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Estrogen Replacement Reduces Oxidative Stress in the Rostral Ventrolateral Medulla of Ovariectomized Rats. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2016:2158971. [PMID: 26640612 PMCID: PMC4657113 DOI: 10.1155/2016/2158971] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 07/06/2015] [Indexed: 02/07/2023]
Abstract
Cardiovascular disease prevalence rises rapidly after menopause, which is believed to be derived from the loss of estrogen. It is reported that sympathetic tone is increased in postmenopause. The high level of oxidative stress in the rostral ventrolateral medulla (RVLM) contributes to increased sympathetic outflow. The focus of this study was to determine if estrogen replacement reduces oxidative stress in the RVLM and sympathetic outflow in the ovariectomized (OVX) rats. The data of this study showed that OVX rat increased oxidative stress in the RVLM and sympathetic tone; estrogen replacement improved cardiovascular functions but also reduced the level of oxidative stress in the RVLM. These findings suggest that estrogen replacement decreases blood pressure and sympathoexcitation in the OVX rats, which may be associated with suppression in oxidative stress in the RVLM through downregulation of protein expression of NADPHase (NOX4) and upregulation of protein expression of SOD1. The data from this study is beneficial for our understanding of the mechanism of estrogen exerting cardiovascular protective effects on postmenopause.
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17
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Oche B, Chen L, Ma YK, Yang Y, Li CX, Geng X, Qiu LZ, Gao XM, Wang H. Cryptotanshinone and wogonin up-regulate eNOS in vascular endothelial cells via ERα and down-regulate iNOS in LPS stimulated vascular smooth muscle cells via ERβ. Arch Pharm Res 2015; 39:249-258. [PMID: 26481132 DOI: 10.1007/s12272-015-0671-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 10/03/2015] [Indexed: 11/28/2022]
Abstract
Phytoestrogens were widely used as natural alternatives to estrogen for treating cardiovascular diseases. They have been reported to have cardioprotective and anti-inflammatory response, but the mechanisms remain unclear. In this study, we found cryptotanshinone and wogonin exhibited phytoestrogenic property in an estrogen-responsive reporter assay. In EA.hy926 cells, treatment of cryptotanshinone and wogonin led to significant increase in NO production levels, which were inhibited by co-incubation of estrogen receptor (ER)α antagonist methyl-piperidino-pyrazole (MPP). The expression of endothelial NO synthase (eNOS) and ERα were up-regulated with the same treatment, indicating they stimulate NO and eNOS expression via ERα-dependent pathway in endothelial cells. While in lipopolysaccharide activated vascular smooth muscle cell line A7r5, cryptotanshinone and wogonin exerted anti-inflammatory effects by inhibiting NO and inducible NO synthase expression via ERβ-dependent pathway. The reduction of NO synthesis was not affected by MPP, and was abrogated by ERβ antagonist R,R-tetrahydrochrysene. Our findings provide the potential molecular mechanism of cryptotanshinone and wogonin as phytoestrogens for their cardioprotective effects, which exerted regulatory effects on NO synthesis through differential regulation of estrogen receptors. It can be employed as a basis for evaluating the beneficial effects of phytoestrogens in the treatment of patients at risk of cardiovascular disease.
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Affiliation(s)
- Barnabas Oche
- Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin, China.,Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, # 312 Anshanxi Road, Nankai District, Tianjin, 300193, China
| | - Lu Chen
- Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin, China.,Tianjin Key Laboratory of Traditional Chinese Medicine Pharmacology, Tianjin, China.,Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, # 312 Anshanxi Road, Nankai District, Tianjin, 300193, China
| | - Ya-Ke Ma
- Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, # 312 Anshanxi Road, Nankai District, Tianjin, 300193, China
| | - Yue Yang
- Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin, China.,Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, # 312 Anshanxi Road, Nankai District, Tianjin, 300193, China
| | - Chun-Xiao Li
- Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin, China.,Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, # 312 Anshanxi Road, Nankai District, Tianjin, 300193, China
| | - Xiao Geng
- Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin, China.,Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, # 312 Anshanxi Road, Nankai District, Tianjin, 300193, China
| | - Li-Zhen Qiu
- Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin, China.,Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, # 312 Anshanxi Road, Nankai District, Tianjin, 300193, China
| | - Xiu-Mei Gao
- Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin, China.,Key Laboratory of Pharmacology of Traditional Chinese Medical Formulae, Ministry of Education, Tianjin University of Traditional Chinese Medicine, Tianjin, China.,Tianjin Key Laboratory of Traditional Chinese Medicine Pharmacology, Tianjin, China
| | - Hong Wang
- Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin, China. .,Tianjin Key Laboratory of Traditional Chinese Medicine Pharmacology, Tianjin, China. .,Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, # 312 Anshanxi Road, Nankai District, Tianjin, 300193, China.
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18
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Choijookhuu N, Hino SI, Oo PS, Batmunkh B, Mohmand NA, Kyaw MTH, Hishikawa Y. Ontogenetic changes in the expression of estrogen receptor β in mouse duodenal epithelium. Clin Res Hepatol Gastroenterol 2015; 39:499-507. [PMID: 25726500 DOI: 10.1016/j.clinre.2015.01.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 12/12/2014] [Accepted: 01/05/2015] [Indexed: 02/07/2023]
Abstract
Estrogen is considered to be involved in duodenal function; however, the details of its receptor expression are largely unknown. The purpose of this study was to determine the expression and localization of estrogen receptors (ERs) in mouse duodenum. Male and female C57BL/6J mouse intestinal tissues were used to investigate the expression of ERα and ERβ by RT-PCR, western blotting, immunohistochemistry, and Southwestern histochemistry. ERβ, but not ERα, was expressed in proximal duodenal epithelium, but not in jejunum and ileum. The expression of ERβ mRNA and protein were confirmed by RT-PCR and western blotting, respectively. At postnatal day 20, the transit period of suckling to weaning, the distribution of ERβ-positive cells was changed in the crypt-villus axis, and cytoplasm/nuclear staining changed to only nuclear staining. Moreover, Southwestern histochemistry was used to detect estrogen response element (ERE)-binding proteins, and their expression pattern was highly similar to that of ERβ. These results suggested that ERβ is the predominant ER type in mouse small intestine, and the highly similar co-localization of ERE-binding proteins reveals that ERβ is functionally active in mouse duodenum. The ERβ expression changes during postnatal development indicate that ERβ may be involved in the differentiation of duodenal epithelium.
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Affiliation(s)
- Narantsog Choijookhuu
- Division of Histochemistry and Cell Biology, Department of Anatomy, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Shin-ichiro Hino
- Division of Histochemistry and Cell Biology, Department of Anatomy, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Phyu Synn Oo
- Division of Histochemistry and Cell Biology, Department of Anatomy, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Baatarsuren Batmunkh
- Division of Histochemistry and Cell Biology, Department of Anatomy, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Noor Ali Mohmand
- Division of Histochemistry and Cell Biology, Department of Anatomy, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Myat Tin Htwe Kyaw
- Division of Histochemistry and Cell Biology, Department of Anatomy, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Yoshitaka Hishikawa
- Division of Histochemistry and Cell Biology, Department of Anatomy, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan.
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19
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Xue B, Zhang Z, Beltz TG, Guo F, Hay M, Johnson AK. Genetic knockdown of estrogen receptor-alpha in the subfornical organ augments ANG II-induced hypertension in female mice. Am J Physiol Regul Integr Comp Physiol 2014; 308:R507-16. [PMID: 25552661 DOI: 10.1152/ajpregu.00406.2014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The present study tested the hypotheses that 1) ERα in the brain plays a key role in the estrogen-protective effects against ANG II-induced hypertension, and 2) that the subfornical organ (SFO) is a key site where ERα mediates these protective actions. In this study, a "floxed" ERα transgenic mouse line (ERα(flox)) was used to create models in which ERα was knocked down in the brain or just in the SFO. Female mice with ERα ablated in the nervous system (Nestin-ERα(-) mice) showed greater increases in blood pressure (BP) in response to ANG II. Furthermore, females with ERα knockdown specifically in the SFO [SFO adenovirus-Cre (Ad-Cre) injected ERα(flox) mice] also showed an enhanced pressor response to ANG II. Immunohistochemical (IHC), RT-PCR, and Western blot analyses revealed a marked reduction in the expression of ERα in nervous tissues and, in particular, in the SFO. These changes were not present in peripheral tissues in Nestin-ERα(-) mice or Ad-Cre-injected ERα(flox) mice. mRNA expression of components of the renin-angiotensin system in the lamina terminalis were upregulated in Nestin-ERα(-) mice. Moreover, ganglionic blockade on day 7 after ANG II infusions resulted in a greater reduction of BP in Nestin-ERα(-) mice or SFO Ad-Cre-injected mice, suggesting that knockdown of ERα in the nervous system or the SFO alone augments central ANG II-induced increase in sympathetic tone. The results indicate that interfering with the action of estrogen on SFO ERα is sufficient to abolish the protective effects of estrogen against ANG II-induced hypertension.
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Affiliation(s)
- Baojian Xue
- Departments of Psychology, University of Iowa, Iowa City, Iowa; and
| | - Zhongming Zhang
- Zhang Zhongjing College of Chinese Medicine, Nanyang Institute of Technology, Henan, China
| | - Terry G Beltz
- Departments of Psychology, University of Iowa, Iowa City, Iowa; and
| | - Fang Guo
- Departments of Psychology, University of Iowa, Iowa City, Iowa; and
| | - Meredith Hay
- Department of Physiology, University of Arizona, Tucson, Arizona; Evelyn F. McKnight Brain Institute, Tucson, Arizona; and
| | - Alan Kim Johnson
- Departments of Psychology, University of Iowa, Iowa City, Iowa; and Department of Pharmacology, University of Iowa, Iowa City, Iowa; François M. Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa
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20
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Rose JL, Hamlin AS, Scott CJ. Sex differences in the expression of estrogen receptor alpha within noradrenergic neurons in the sheep brain stem. Domest Anim Endocrinol 2014; 49:6-13. [PMID: 25010022 DOI: 10.1016/j.domaniend.2014.04.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 04/15/2014] [Accepted: 04/17/2014] [Indexed: 01/08/2023]
Abstract
In female sheep, high levels of estrogen exert a positive feedback action on gonadotropin releasing hormone (GnRH) secretion to stimulate a surge in luteinizing hormone (LH) secretion. Part of this action appears to be via brain stem noradrenergic neurons. By contrast, estrogen action in male sheep has a negative feedback action to inhibit GnRH and LH secretion. To investigate whether part of this sex difference is due to differences in estrogen action in the brain stem, we tested the hypothesis that the distribution of estrogen receptor α (ERα) within noradrenergic neurons in the brain stem differs between rams and ewes. To determine the distribution of ERα, we used double-label fluorescence immunohistochemistry for dopamine β-Hydroxylase, as a marker for noradrenergic and adrenergic cells, and ERα. In the ventrolateral medulla (A1 region), most ERα-immunoreactive (-ir) cells were located in the caudal part of the nucleus. Overall, there were more ERα-ir cells in rams than ewes, but the proportion of double-labeled cells was did not differ between sexes. Much greater numbers of ERα-ir cells were found in the nucleus of the solitary tract (A2 region), but <10% were double labeled and there were no sex differences. The majority of ERα-labeled cells in this nucleus was located in the more rostral areas. ERα-labeled cells were found in several rostral brain stem regions but none of these were double labeled and so were not quantified. Because there was no sex difference in the number of ERα-ir cells in the brain stem that were noradrenergic, the sex difference in the action of estrogen on gonadotropin secretion in sheep is unlikely to involve actions on brain stem noradrenergic cells.
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Affiliation(s)
- J L Rose
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, North South Wales, Australia; Graham Centre for Agricultural Innovation, Charles Sturt University and NSW Department of Primary Industries, Australia
| | - A S Hamlin
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, North South Wales, Australia
| | - C J Scott
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, North South Wales, Australia; Graham Centre for Agricultural Innovation, Charles Sturt University and NSW Department of Primary Industries, Australia.
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21
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Zuloaga DG, Zuloaga KL, Hinds LR, Carbone DL, Handa RJ. Estrogen receptor β expression in the mouse forebrain: age and sex differences. J Comp Neurol 2014; 522:358-71. [PMID: 23818057 DOI: 10.1002/cne.23400] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 02/15/2012] [Accepted: 06/19/2012] [Indexed: 12/11/2022]
Abstract
Estrogen receptors regulate multiple brain functions, including stress, sexual, and memory-associated behaviors as well as controlling neuroendocrine and autonomic function. During development, estrogen signaling is involved in programming adult sex differences in physiology and behavior. Expression of estrogen receptor α changes across development in a region-specific fashion. By contrast, estrogen receptor β (ERβ) is expressed in many brain regions, yet few studies have explored sex and developmental differences in its expression, largely because of the absence of selective reagents for anatomical localization of the protein. This study utilized bacterial artificial chromosome transgenic mice expressing ERβ identified by enhanced green fluorescent protein (EGFP) to compare expression levels and distribution of ERβ in the male and female mouse forebrain on the day of birth (P0), on postnatal day 4 (P4), and on P21. By using qualitative analysis, we mapped the distribution of ERβ-EGFP and found developmental alterations in ERβ expression within the cortex, hippocampus, and hypothalamic regions including the arcuate, ventromedial, and paraventricular nuclei. We also report a sex difference in ERβ in the bed nucleus of the stria terminalis, with males showing greater expression at P4 and P21. Another sex difference was found in the anteroventral periventricular nucleus of P21, but not P0 or P4, mice, in which ERβ-EGFP-immunoreactive cells were densely clustered near the third ventricle in females but not males. These developmental changes and sex differences in ERβ indicate a mechanism through which estrogens might differentially affect brain functions or program adult physiology at select times during development.
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Affiliation(s)
- Damian G Zuloaga
- Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, 85004-2157
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22
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Knowlton AA, Korzick DH. Estrogen and the female heart. Mol Cell Endocrinol 2014; 389:31-9. [PMID: 24462775 PMCID: PMC5709037 DOI: 10.1016/j.mce.2014.01.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 01/04/2014] [Accepted: 01/05/2014] [Indexed: 12/24/2022]
Abstract
Estrogen has a plethora of effects in the cardiovascular system. Studies of estrogen and the heart span human clinical trials and basic cell and molecular investigations. Greater understanding of cell and molecular responses to estrogens can provide further insights into the findings of clinical studies. Differences in expression and cellular/intracellular distribution of the two main receptors, estrogen receptor (ER) α and β, are thought to account for the specificity and differences in responses to estrogen. Much remains to be learned in this area, but cellular distribution within the cardiovascular system is becoming clearer. Identification of GPER as a third ER has introduced further complexity to the system. 17β-estradiol (E2), the most potent human estrogen, clearly has protective properties activating a signaling cascade leading to cellular protection and also influencing expression of the protective heat shock proteins (HSP). E2 protects the heart from ischemic injury in basic studies, but the picture is more involved in the whole organism and clinical studies. Here the complexity of E2's widespread effects comes into play and makes interpretation of findings more challenging. Estrogen loss occurs primarily with aging, but few studies have used aged models despite clear evidence of differences between the response to estrogen deficiency in adult and aged animals. Thus more work is needed focusing on the effects of aging vs. estrogen loss on the cardiovascular system.
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Affiliation(s)
- A A Knowlton
- The Department of Veteran's Affairs, Northern California VA, Sacramento, CA, USA; Molecular & Cellular Cardiology, Departments of Medicine and Pharmacology, University of California, Davis, USA.
| | - D H Korzick
- Intercollege Program in Physiology and Department of Kinesiology, The Pennsylvania State University, University Park, PA, USA
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23
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Muñoz-Castañeda R, Díaz D, Avila-Zarza CA, Alonso JR, Weruaga E. Sex-influence of nicotine and nitric oxide on motor coordination and anxiety-related neurophysiological responses. Psychopharmacology (Berl) 2014; 231:695-706. [PMID: 24081550 DOI: 10.1007/s00213-013-3284-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 09/07/2013] [Indexed: 10/26/2022]
Abstract
RATIONALE Nitric oxide (NO) is a messenger synthesized in both the neuronal and glial populations by nitric oxide synthase type 1 (NOS1). Nicotine regulates NO production in a sex-dependent manner, both molecules being involved in motor function. OBJECTIVE The present study evaluates sex differences in motor coordination, general movement, and anxiety-related responses resulting from both constant and continuous nicotine treatment and the genetic depletion of NOS1 activity. METHODS Male and female mice were analyzed with the open-field and the rotarod tests. To understand the role of NO, knockout mice for NOS1 (NOS1-/-) were analyzed. Nicotine was administered continuously at a dose of 24 mg/kg/day via osmotic mini-pumps over 14 days because the behavioral effects elicited are similar to those observed with discontinuous administration. RESULTS Data analyses revealed noteworthy sex differences derived from NOS1 depletion. Control NOS1-/- males exhibited an exacerbated anxiety-related response in relation to control NOS1-/- females and control wild-type (WT) males; these differences disappeared in the nicotine-administered NOS1-/- males. Additionally, nicotine administration differentially affected the horizontal movements of NOS1-/- females with respect to WT animals. NO depletion affected male but not female motor coordination improvement along the test days. However, the drug affected female motor coordination only at the end of the administration period. CONCLUSIONS We show for the first time that NO affects motor and anxiety behaviors in a sex-dependent manner. Moreover, the behavioral effects of constant nicotine administration are dimorphic and dependent on NO production.
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Affiliation(s)
- Rodrigo Muñoz-Castañeda
- Laboratory of Neural Plasticity and Neurorepair, Institute for Neuroscience of Castilla y León (INCyL), Universidad de Salamanca, C/ Pintor Fernando Gallego 1, 37007, Salamanca, Spain
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24
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Xue B, Johnson AK, Hay M. Sex differences in angiotensin II- and aldosterone-induced hypertension: the central protective effects of estrogen. Am J Physiol Regul Integr Comp Physiol 2013; 305:R459-63. [PMID: 23883676 DOI: 10.1152/ajpregu.00222.2013] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Premenopausal women have lower blood pressure and a reduced incidence of cardiovascular disease compared with age-matched men. Similar sex differences have been seen across species and in multiple animal models of hypertension. While important progress over the last decade has been made in elucidating some of the mechanisms underlying these differences, there are still significant gaps in our knowledge. Understanding the cellular and molecular mechanisms responsible for sex differences in hypertension will be important for developing sex-specific therapies targeted toward the prevention and treatment of hypertension. Female sex hormones, especially estrogen, have been demonstrated to modulate the renin-angiotensin-aldosterone system (RAAS) and to have beneficial effects on cardiovascular function through actions not only on the kidney, heart, and vasculature, but also on the central nervous system (CNS). This review primarily focuses on the central regulatory actions of estrogen on brain nuclei involved in blood pressure regulation and the interactions between estrogen and the RAAS in the CNS by which estrogen plays an important protective role against the development of hypertension.
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Affiliation(s)
- Baojian Xue
- Department of Psychology, The University of Iowa, Iowa, USA
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25
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Xue B, Zhang Z, Beltz TG, Johnson RF, Guo F, Hay M, Johnson AK. Estrogen receptor-β in the paraventricular nucleus and rostroventrolateral medulla plays an essential protective role in aldosterone/salt-induced hypertension in female rats. Hypertension 2013; 61:1255-62. [PMID: 23608653 DOI: 10.1161/hypertensionaha.111.00903] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The identification of the specific estrogen receptor (ER) subtypes that are involved in estrogen protection from hypertension and their specific locations in the central nervous system is critical to our understanding and design of effective estrogen replacement therapies in women. Using selective ER agonists and recombinant adeno-associated virus (AAV) carrying small interference (si) RNA to silence either ERα (AAV-siRNA-ERα) or ERβ (AAV-siRNA-ERβ), the present study investigated regional specificity of different ER subtypes in the protective actions of estrogen in aldosterone (Aldo)-induced hypertension. Intracerebroventricular infusions of either diarylpropionitrile, a selective ERβ agonist, or propyl-pyrazole-triol, a selective ERα agonist, attenuated Aldo/NaCl-induced hypertension in ovariectomized rats. In contrast, intracerebroventricular injections of siRNA-ERα or siRNA-ERβ augmented Aldo-induced hypertension in intact females. Site-specific paraventricular nucleus (PVN) or rostroventrolateral medulla (RVLM) injections of siRNA-ERβ augmented Aldo-induced hypertension. However, rats with PVN or RVLM injections of siRNA-ERα did not significantly increase blood pressure induced by Aldo. Real-time polymerase chain reaction analyses of the PVN and RVLM of siRNA-injected rat confirmed a marked reduction in the expression of ERα and ERβ. In cultured PVN neurons, silencing either ERα or ERβ by culturing PVN neurons with siRNA-ERα or siRNA-ERβ enhanced Aldo-induced reactive oxygen species production. Ganglionic blockade after Aldo infusion showed an increase in sympathetic activity in ERβ knockdown rats. These results indicate that both PVN and RVLM ERβ, but not ERα in these nuclei, contribute to the protective effects of estrogen against Aldo-induced hypertension. The brain regions responsible for the protective effects of estrogen interaction with ERα in Aldo-induced hypertension still need to be determined.
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Affiliation(s)
- Baojian Xue
- Department of Psychology, The University of Iowa, 11 Seashore Hall E, Iowa City, IA 52242, USA.
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Korzick DH, Lancaster TS. Age-related differences in cardiac ischemia-reperfusion injury: effects of estrogen deficiency. Pflugers Arch 2013; 465:669-85. [PMID: 23525672 DOI: 10.1007/s00424-013-1255-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2013] [Revised: 02/23/2013] [Accepted: 02/25/2013] [Indexed: 01/17/2023]
Abstract
Despite conflicting evidence for the efficacy of hormone replacement therapy in cardioprotection of postmenopausal women, numerous studies have demonstrated reductions in ischemia/reperfusion (I/R) injury following chronic or acute exogenous estradiol (E2) administration in adult male and female, gonad-intact and gonadectomized animals. It has become clear that ovariectomized adult animals may not accurately represent the combined effects of age and E2 deficiency on reductions in ischemic tolerance seen in the postmenopausal female. E2 is known to regulate the transcription of several cardioprotective genes. Acute, non-genomic E2 signaling can also activate many of the same signaling pathways recruited in cardioprotection. Alterations in cardioprotective gene expression or cardioprotective signal transduction are therefore likely to result within the context of aging and E2 deficiency and may help explain the reduced ischemic tolerance and loss of cardioprotection in the senescent female heart. Quantification of the mitochondrial proteome as it adapts to advancing age and E2 deficiency may also represent a key experimental approach to uncover proteins associated with disruptions in cardiac signaling contributing to age-associated declines in ischemic tolerance. These alterations have important ramifications for understanding the increased morbidity and mortality due to ischemic cardiovascular disease seen in postmenopausal females. Functional perturbations that occur in mitochondrial respiration and Ca(2+) sensitivity with age-associated E2 deficiency may also allow for the identification of alternative therapeutic targets for reducing I/R injury and treatment of the leading cause of death in postmenopausal women.
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Affiliation(s)
- Donna H Korzick
- Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, USA.
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Hatam M, Ganjkhani M. Effect of GABA(A) Receptors in the Rostral Ventrolateral Medulla on Cardiovascular Response to the Activation of the Bed Nucleus of the Stria Terminalis in Female Ovariectomized Rats. IRANIAN JOURNAL OF MEDICAL SCIENCES 2012; 37:242-52. [PMID: 23390330 PMCID: PMC3565197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Revised: 02/14/2012] [Accepted: 02/19/2012] [Indexed: 10/25/2022]
Abstract
BACKGROUND The areas of the bed nucleus of the stria terminalis (BST) with a high density of estrogen receptors are involved in cardiovascular regulation and send axonal projections to the rostroventrolateral medulla (RVLM). We aimed to find the contribution of the RVLM to cardiovascular responses elicited by glutamate microinjection into the BST. METHODS Experiments were done in α-chloralose anesthetized ovariectomized (OVX) or OVX estrogen treated (OVX+E) female Wistar rats. Drugs were microinjected into the BST and RVLM. The average changes in mean arterial pressure (MAP) and heart rate (HR) were compared between the case and control groups using t test and with the pre-injection values using paired t test. RESULTS Unilateral microinjection of glutamate (0.25 M/50 nl) into the BST decreased MAP and HR, in the OVX+E and OVX rats. These cardiovascular responses were reversibly attenuated 10 minutes after microinjection of synaptic blocker cobalt chloride (CoCl(2), 5 mM/50 nl) into the ipsilateral RVLM. Re-stimulation of the BST 60 min after CoCl(2) injection elicited cardiovascular responses that were not different from the control values. Ipsilateral microinjection of GABA(A) antagonist bicuculline (1.0 mM/50 nl) into the RVLM caused a 50% attenuation of glutamate induced depressor and bradycardic responses in both groups. Ipsilateral microinjection of GABA(B) antagonist, phaclophen (5.0 mM/50 nl), into the RVLM did not affect the depressor and bradycardic responses due to re-stimulation of the BST by glutamate. CONCLUSION The RVLM sympathetic premotor neurons contain GABA(A) receptors that mediate in part the sympathoinhibitory responses to stimulation of the BST in the OVX animals.
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Affiliation(s)
- Masoumeh Hatam
- Department of Physiology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mahin Ganjkhani
- Department of Physiology and Pharmacology, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
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Estradiol receptors agonists induced effects in rat intestinal microcirculation during sepsis. Microvasc Res 2012; 85:118-27. [PMID: 23063870 DOI: 10.1016/j.mvr.2012.10.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 10/02/2012] [Accepted: 10/03/2012] [Indexed: 01/26/2023]
Abstract
The steroid hormone estradiol is suggested to play a protective role in intestinal injury during systemic inflammation (sepsis). Our aim was to determine the effects of specific estradiol receptor (ER-α and ER-ß) agonists on the intestinal microcirculation during experimental sepsis. Male and sham ovariectomized female rats were subjected to sham colon ascendens stent peritonitis (CASP), and they were compared to male and ovariectomized female rats underwent CASP and either estradiol receptor α (ER-α) agonist propyl pyrazole triol (PPT), estradiol receptor ß (ER-ß) agonist diarylpropiolnitrile (DPN), or vehicle treatment. Intravital microscopy was performed, which is sufficiently sensitive to measure changes in the functional capillary density (FCD) as well as the major steps in leukocyte recruitment (rolling and adhesion). The leukocyte extravasations were also quantified by using histological paraffin sections of formalin fixed intestine. We found that either DPN (ER-β) or PPT (ER-α) significantly reduced (P<0.05) sepsis-induced leukocyte-endothelial interaction (rolling, adherent leukocytes and neutrophil extravasations) and improved the intestinal muscular FCD. [PPT: Female; Leukocyte rolling (n/min): V(3) 3.7±0.7 vs 0.8±0.2, Leukocyte adhesion(n/mm(2)): V(3) 131.3±22.6 vs 57.2±13.5, Neutrophil extravasations (n/10000 μm(2)): 3.1±0.7 vs 6 ±1. Male; Leukocyte adhesion (n/mm(2)): V(1) 154.8±19.2 vs 81.3±11.2, V(3) 115.5±23.1 vs 37.8±12]. [DPN: Female; neutrophil extravasations (n/10000 μm(2)) 3.8±0.6 vs 6 ±1. Male; Leukocyte adhesion (n/mm(2)) V(1) 154.8±19.2 vs 70±10.5, V(3) 115.5±23.1 vs 52.8±9.6].Those results suggest that the observed effects of estradiol receptors on different phases of leukocytes recruitment with the improvement of the functional capillary density could partially explain the previous demonstrated salutary effects of estradiol on the intestinal microcirculation during sepsis. The observed activity of this class of compounds could open up a new avenue of research into the potential treatment of sepsis.
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Wu KLH, Chen CH, Shih CD. Nontranscriptional activation of PI3K/Akt signaling mediates hypotensive effect following activation of estrogen receptor β in the rostral ventrolateral medulla of rats. J Biomed Sci 2012; 19:76. [PMID: 22897791 PMCID: PMC3438069 DOI: 10.1186/1423-0127-19-76] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 08/01/2012] [Indexed: 12/22/2022] Open
Abstract
Background Estrogen acts on the rostral ventrolateral medulla (RVLM), where sympathetic premotor neurons are located, to elicit vasodepressor effects via an estrogen receptor (ER)β-dependent mechanism. We investigated in the present study nontranscriptional mechanism on cardiovascular effects following activation of ERβ in the RVLM, and delineated the involvement of phosphatidylinositol 3-kinase (PI3K)/serine/threonine kinase (Akt) signaling pathway in the effects. Methods In male Sprague–Dawley rats maintained under propofol anesthesia, changes in arterial pressure, heart rate and sympathetic neurogenic vasomotor tone were examined after microinjection bilaterally into RVLM of 17β-estradiol (E2β) or a selective ERα or ERβ agonist. Involvement of ER subtypes and PI3K/Akt signaling pathway in the induced cardiovascular effects were studied using pharmacological tools of antagonists or inhibitors, gene manipulation with antisense oligonucleotide (ASON) or adenovirus-mediated gene transfection. Results Similar to E2β (1 pmol), microinjection of ERβ agonist, diarylpropionitrile (DPN, 1, 2 or 5 pmol), into bilateral RVLM evoked dose-dependent hypotension and reduction in sympathetic neurogenic vasomotor tone. These vasodepressive effects of DPN (2 pmol) were inhibited by ERβ antagonist, R,R-tetrahydrochrysene (50 pmol), ASON against ERβ mRNA (250 pmol), PI3K inhibitor LY294002 (5 pmol), or Akt inhibitor (250 pmol), but not by ERα inhibitor, methyl-piperidino-pyrazole (1 nmol), or transcription inhibitor, actinomycin D (5 or 10 nmol). Gene transfer by microinjection into bilateral RVLM of adenovirus encoding phosphatase and tensin homologues deleted on chromosome 10 (5 × 108 pfu) reversed the vasodepressive effects of DPN. Conclusions Our results indicate that vasodepressive effects following activation of ERβ in RVLM are mediated by nongenomic activation of PI3K/Akt signaling pathway. This study provides new insight in the intracellular signaling cascades involved in central vasodepressive functions of estrogen.
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Affiliation(s)
- Kay L H Wu
- Department of Pharmacy, Graduate Institute of Pharmaceutical Technology, Tajen University, 20 Weishin Road, Yanpu Township, Pingtung County 90741, Taiwan
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Karami R, Hosseini M, Khodabandehloo F, Khatami L, Taiarani Z. Different effects of L-arginine on morphine tolerance in sham and ovariectomized female mice. J Zhejiang Univ Sci B 2012; 12:1016-23. [PMID: 22135151 DOI: 10.1631/jzus.b1100029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE The roles of gonadal hormones and nitric oxide (NO) on the analgesic effects of morphine, tolerance to morphine, and their interactions have been widely investigated. In the present study, the effect of L-arginine (an NO precursor) on morphine tolerance in sham and ovariectomized (OVX) female mice was investigated. METHODS Forty mice were divided into sham and OVX groups. On the first day, a hot plate test ((55±0.2) °C; cut-off 30 s) was carried out as a base record 15 min before injection of morphine (10 mg/kg, subcutaneously (s.c.)) and was repeated every 15 min after injection. The sham group was then divided into two subgroups: sham-tolerance-L-arginine (Sham-Tol-LA) and sham-tolerance-saline (Sham-Tol-Sal) which received either L-arginine 50 mg/kg (intraperitoneally (i.p.)) or saline 10 ml/kg (i.p.), respectively, three times in a day for three consecutive days. Morphine tolerance was induced in animals by injecting 30 mg/kg morphine (s.c.) three times/day for three days. This treatment was also used for OVX subgroups. On the fifth day, the hot plate test was repeated. The analgesic effect of morphine was calculated as the maximal percent effect (MPE). The results were compared using repeated measure analysis of variance (ANOVA). RESULTS There was no significant difference in MPE between the OVX and sham groups. The MPEs in both the Sham-Tol-Sal and OVX-Tol-Sal groups were lower than those in both the sham and OVX groups (P<0.01). The MPE in the OVX-Tol-Sal group was greater than that in the Sham-Tol-Sal group (P<0.01). The MPE in the Sham-Tol-LA group was higher than that in the Sham-Tol-Sal group (P<0.01). However, there was no significant difference between the Sham-Tol-LA and sham groups or between the OVX-Tol-LA and OVX-Tol-Sal groups. CONCLUSIONS The results of the present study showed that repeated administration of morphine causes tolerance to the analgesic effect of morphine. L-arginine could prevent tolerance to morphine but its effect was different in the presence of ovarian hormones.
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Affiliation(s)
- Reza Karami
- Neuroscience Research Center and Department of Physiology, School of Medicine, Mashhad University of Medical Sciences, Iran
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Tomicek NJ, Miller-Lee JL, Hunter JC, Korzick DH. Estrogen receptor beta does not influence ischemic tolerance in the aged female rat heart. Cardiovasc Ther 2011; 31:32-7. [PMID: 21884022 DOI: 10.1111/j.1755-5922.2011.00288.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
INTRODUCTION Ischemic heart disease remains the leading cause of morbidity and mortality in aged women, with a 2- to 3-fold increase in incidence following menopause. Clinical trials have failed to demonstrate cardioprotective benefit from chronic estrogen (E(2)) replacement therapy, yet protective effects of E(2) have been demonstrated in adult animal models and are mediated by the estrogen receptor (ER) subtypes ERα and ERβ. AIMS The aim of this study was to determine the effects of acute ERβ activation on ischemia/reperfusion (I/R) injury in adult, aged, and aged E(2)-deficient female rats. METHODS Hearts were isolated from adult (6 months; n = 9), aged (24 months; n = 13), and aged ovariectomized (OVX; n = 14) female Fischer 344 rats and subjected to 47 min of global I and 60 min of R. Rats were acutely treated with the ERβ-agonist diarylpropionitrile (DPN; 5 μg/kg) or vehicle 45 min prior to I/R; ERβ mRNA and protein levels were also assessed. RESULTS Acute treatment with DPN had no effect on functional recovery following I/R injury in adult, aged, or aged OVX female rats. Additionally, we were unable to detect ERβ mRNA or protein in the adult or aged female rat myocardium. CONCLUSIONS Here, for the first time, our data suggest that acute ERβ activation does not impact ischemic tolerance in the adult or aged female Fischer 344 rat myocardium and this likely due to a lack of detectable ERβ.
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Affiliation(s)
- Nanette J Tomicek
- Intercollege Graduate Degree Program in Physiology, The Pennsylvania State University, University Park, PA 16802, USA
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