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The effect of gender and obesity in modulating cross-bridge function in cardiac muscle fibers. J Muscle Res Cell Motil 2022; 43:157-172. [PMID: 35994221 DOI: 10.1007/s10974-022-09627-z] [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: 05/13/2022] [Accepted: 07/11/2022] [Indexed: 12/31/2022]
Abstract
The effect of obesity on cross-bridge (CB) function was investigated in mice lacking functional Melanocortin-4 Receptor (MC4R-/-), the loss of which causes dilated cardiomyopathy (DCM) in humans and mice. Skinned cardiac muscle fibers from male and female mice were used, and activated in the presence of Ca2+. To characterize CB kinetics, we changed the length of fibers in sinewaves (15 frequencies: 1‒187 Hz) at a small amplitude (0.2%L0), studied concomitant tension transients, and deduced the kinetic constants of the CB cycle from the ATP and Pi effects. In males, active tension and stiffness during full activation and rigor were ~ 1.5X in WT compared to MC4R-/- mice. This effect was not observed in females. We also observed that ATP binding and subsequent CB detachment steps were not altered by the mutation/gender. The equilibrium constant of the force generation step (K4) and Pi release step (association constant: K5) were not affected by the mutation, but there was a gender difference in WT mice: K4 and K5 were ~ 2.2X in males than in females. Concomitantly, the forward rate constant (r4) and backward rate constant (r-4) of the force generation step were 1.5-2.5X in muscles from female MC4R-/- mice relative to male MC4R-/- mice. However, these effects did not cause a significant difference in CB distributions among six CB states. In both genders, Ca2+ sensitivity decreased slightly (0.12 pCa unit) in mutants. We conclude that the CB functions are differentially affected both by obesity induced in the absence of functional MC4R-/- and gender.
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Najaftomaraei M, Ghorbani A, Rahimi A, Mohebbati R, Sherkat S, Shafei MN. The role of nitric oxide in the dorsomedial periaqueductal gray (dmPAG) column in cardiovascular responses in urethane-anesthetized male rats. Animal Model Exp Med 2022; 5:557-564. [PMID: 36415083 PMCID: PMC9773306 DOI: 10.1002/ame2.12292] [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: 07/15/2022] [Accepted: 10/26/2022] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND The dorsomedial periaqueductal gray (dmPAG) is a mesencephalic area and has numerous functions including cardiovascular regulation. Because nitric oxide (NO) is present in the dmPAG, here we investigate, the probable cardiovascular effect of NO in the dmPAG. METHODS Five groups (n = 6 for each group) were used as follows: (1) control; (2) L-NAME (NG -nitro-L-arginine methyl ester, a NO synthase inhibitor, 90 nmol); (3) L-arginine (L-Arg, a precursor for NO, 60 nmol); (4) Sodium nitroprusside (SNP, a NO donor, 27 nmol); and (5) L-Arg + L-NAME. The cardiovascular parameters were recorded by a Power Lab device after cannulation of the femoral artery. Drugs were injected using a stereotaxic instrument. The changes (∆) in systolic blood pressure (SBP), mean arterial pressure (MAP), and heart rate (HR) were calculated at different times and compared to the control group. RESULTS Microinjection of L-NAME significantly increased ∆SBP, ∆MAP, and ∆HR more than saline (from p < 0.05 to p < 0.001). L-Arg only significantly increased ∆HR (p < 0.05). In the L-Arg + L-NAME group, the above parameters also significantly increased (from p < 0.01 to p < 0.05) but not as significantly as with L-NAME alone. Microinjection of SNP significantly decreased ∆SBP and ∆MAP more than in the control and L-NAME groups (from p < 0.01 to p < 0.001), but ∆HR did not change significantly. CONCLUSION The results indicated that NO in dmPAG has an inhibitory effect on cardiovascular responses in anesthetized rats.
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Affiliation(s)
- Mohammad Najaftomaraei
- Department of Physiology, Faculty of MedicineMashhad University of Medical SciencesMashhadIran
| | - Atiyeh Ghorbani
- Department of Physiology, Faculty of MedicineMashhad University of Medical SciencesMashhadIran
| | - Alireza Rahimi
- Material Science and Metallurgy EngineeringIslamic Azad University ‐ Karaj BranchKarajIran
| | - Reza Mohebbati
- Department of Physiology, Faculty of MedicineGonabad University of Medical SciencesGonabadIran,Applied Biomedical Research CenterMashhad University of Medical SciencesMashhadIran
| | - Sogol Sherkat
- Department of Physiology, School of MedicineSabzevar University of Medical SciencesSabzevarIran
| | - Mohammad Naser Shafei
- Department of Physiology, School of MedicineSabzevar University of Medical SciencesSabzevarIran,Division of Neurocognitive Sciences, Psychiatry and Behavioral Sciences Research CenterMashhad University of Medical SciencesMashhadIran
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Copperi F, Kim JD, Diano S. Role of the Melanocortin System in the Central Regulation of Cardiovascular Functions. Front Physiol 2021; 12:725709. [PMID: 34512392 PMCID: PMC8424695 DOI: 10.3389/fphys.2021.725709] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 07/30/2021] [Indexed: 11/18/2022] Open
Abstract
Increasing evidence indicates that the melanocortin system is not only a central player in energy homeostasis, food intake and glucose level regulation, but also in the modulation of cardiovascular functions, such as blood pressure and heart rate. The melanocortins, and in particular α- and γ-MSH, have been shown to exert their cardiovascular activity both at the central nervous system level and in the periphery (e.g., in the adrenal gland), binding their receptors MC3R and MC4R and influencing the activity of the sympathetic nervous system. In addition, some studies have shown that the activation of MC3R and MC4R by their endogenous ligands is able to improve the outcome of cardiovascular diseases, such as myocardial and cerebral ischemia. In this brief review, we will discuss the current knowledge of how the melanocortin system influences essential cardiovascular functions, such as blood pressure and heart rate, and its protective role in ischemic events, with a particular focus on the central regulation of such mechanisms.
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Affiliation(s)
- Francesca Copperi
- Institute of Human Nutrition, Columbia University Irving Medical Center, New York, NY, United States
| | - Jung Dae Kim
- Institute of Human Nutrition, Columbia University Irving Medical Center, New York, NY, United States
| | - Sabrina Diano
- Institute of Human Nutrition, Columbia University Irving Medical Center, New York, NY, United States.,Department of Molecular Pharmacology and Therapeutics, Columbia University Irving Medical Center, New York, NY, United States.,Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY, United States
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Li Y, Feng Y, Liu L, Li X, Li XY, Sun X, Li KX, Zha RR, Wang HD, Zhang MD, Fan XX, Wu D, Fan Y, Zhang HC, Qiao GF, Li BY. The baroreflex afferent pathway plays a critical role in H 2S-mediated autonomic control of blood pressure regulation under physiological and hypertensive conditions. Acta Pharmacol Sin 2021; 42:898-908. [PMID: 33154555 PMCID: PMC8149652 DOI: 10.1038/s41401-020-00549-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 09/24/2020] [Indexed: 02/07/2023] Open
Abstract
Hydrogen sulfide (H2S), which is closely related to various cardiovascular disorders, lowers blood pressure (BP), but whether this action is mediated via the modification of baroreflex afferent function has not been elucidated. Therefore, the current study aimed to investigate the role of the baroreflex afferent pathway in H2S-mediated autonomic control of BP regulation. The results showed that baroreflex sensitivity (BRS) was increased by acute intravenous NaHS (a H2S donor) administration to renovascular hypertensive (RVH) and control rats. Molecular expression data also showed that the expression levels of critical enzymes related to H2S were aberrantly downregulated in the nodose ganglion (NG) and nucleus tractus solitarius (NTS) in RVH rats. A clear reduction in BP by the microinjection of NaHS or L-cysteine into the NG was confirmed in both RVH and control rats, and a less dramatic effect was observed in model rats. Furthermore, the beneficial effects of NaHS administered by chronic intraperitoneal infusion on dysregulated systolic blood pressure (SBP), cardiac parameters, and BRS were verified in RVH rats. Moreover, the increase in BRS was attributed to activation and upregulation of the ATP-sensitive potassium (KATP) channels Kir6.2 and SUR1, which are functionally expressed in the NG and NTS. In summary, H2S plays a crucial role in the autonomic control of BP regulation by improving baroreflex afferent function due at least in part to increased KATP channel expression in the baroreflex afferent pathway under physiological and hypertensive conditions.
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Affiliation(s)
- Ying Li
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
- Department of Pharmacy, PLA Rocket Force Characteristic Medical Center, Beijing, 100088, China
| | - Yan Feng
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
- Department of Biomedical Engineering, Indiana University-Purdue University, Indianapolis, IN, 46202, USA
| | - Li Liu
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | - Xue Li
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | - Xin-Yu Li
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | - Xun Sun
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
- Department of Biomedical Engineering, Indiana University-Purdue University, Indianapolis, IN, 46202, USA
| | - Ke-Xin Li
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
- Department of Biomedical Engineering, Indiana University-Purdue University, Indianapolis, IN, 46202, USA
| | - Rong-Rong Zha
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
- Department of Biomedical Engineering, Indiana University-Purdue University, Indianapolis, IN, 46202, USA
| | - Hong-Dan Wang
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | - Meng-di Zhang
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
- Department of Physics, School of Science, Indiana University-Purdue University, Indianapolis, IN, 46202, USA
| | - Xiong-Xiong Fan
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | - Di Wu
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | - Yao Fan
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | - Hao-Cheng Zhang
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | - Guo-Fen Qiao
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | - Bai-Yan Li
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China.
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α-Melanocyte-Stimulating Hormone Attenuates Neovascularization by Inducing Nitric Oxide Deficiency via MC-Rs/PKA/NF-κB Signaling. Int J Mol Sci 2018; 19:ijms19123823. [PMID: 30513637 PMCID: PMC6321109 DOI: 10.3390/ijms19123823] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Revised: 11/27/2018] [Accepted: 11/27/2018] [Indexed: 12/13/2022] Open
Abstract
α-melanocyte-stimulating hormone (α-MSH) has been characterized as a novel angiogenesis inhibitor. The homeostasis of nitric oxide (NO) plays an important role in neovascularization. However, it remains unclear whether α-MSH mitigates angiogenesis through modulation of NO and its signaling pathway. The present study elucidated the function and mechanism of NO signaling in α-MSH-induced angiogenesis inhibition using cultured human umbilical vein endothelial cells (HUVECs), rat aorta rings, and transgenic zebrafish. By Griess reagent assay, it was found α-MSH dose-dependently reduced the NO release in HUVECs. Immunoblotting and immunofluorescence analysis revealed α-MSH potently suppressed endothelial and inducible nitric oxide synthase (eNOS/iNOS) expression, which was accompanied with inhibition of nuclear factor kappa B (NF-κB) activities. Excessive supply of NO donor l-arginine reversed the α-MSH-induced angiogenesis inhibition in vitro and in vivo. By using antibody neutralization and RNA interference, it was delineated that melanocortin-1 receptor (MC1-R) and melanocortin-2 receptor (MC2-R) participated in α-MSH-induced inhibition of NO production and NF-κB/eNOS/iNOS signaling. This was supported by pharmaceutical inhibition of protein kinase A (PKA), the downstream effector of MC-Rs signaling, using H89 abolished the α-MSH-mediated suppression of NO release and eNOS/iNOS protein level. Therefore, α-MSH exerts anti-angiogenic function by perturbing NO bioavailability and eNOS/iNOS expression in endothelial cells.
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Vaglini F, Pardini C, Di Desidero T, Orlandi P, Pasqualetti F, Ottani A, Pacini S, Giuliani D, Guarini S, Bocci G. Melanocortin Receptor-4 and Glioblastoma Cells: Effects of the Selective Antagonist ML00253764 Alone and in Combination with Temozolomide In Vitro and In Vivo. Mol Neurobiol 2017; 55:4984-4997. [DOI: 10.1007/s12035-017-0702-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 07/31/2017] [Indexed: 12/13/2022]
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7
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Shafei MN, Nikyar T, Hosseini M, Niazmand S, Paseban M. Cardiovascular effects of nitrergic system of the pedunculopontine tegmental nucleus in anesthetized rats. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2017; 20:776-782. [PMID: 28852442 PMCID: PMC5569585 DOI: 10.22038/ijbms.2017.9009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 05/25/2017] [Indexed: 12/16/2022]
Abstract
OBJECTIVES Nitric oxide (NO) is an important neurotransmitter in central nervous system involved in central cardiovascular regulation. The presence of NO in the pedunculopontine tegmental (PPT) nucleus has been shown, but its cardiovascular effect has not been determined. In the present study, the cardiovascular effect of NO in the PPT nucleus was evaluated. MATERIALS AND METHODS After induction of anesthesia, a polyethylene catheter (PE-50) filled with heparinized saline inserted into the femoral artery, and the blood pressure (BP) and heart rate (HR) were continuously recorded. Animals were then placed in a stereotaxic apparatus and maximum changes of mean arterial pressure (∆MAP) and heart rate (∆HR) after microinjection of two doses of NG-nitro-L-arginine methyl ester (L-NAME, 30 and 90 nmol), L-arginine (L-Arg 10 and 50 nmol) and sodium nitroprusside (SNP, 9 and 27 nmol) into the PPT were provided and compared with control group (One-way ANOVA). RESULTS Both doses of L-NAME significantly increased ∆MAP compared to control (P<0.05 and P<0.01, respectively). ∆HR only in higher dose (90 nmol) significantly increased compared to control (P<0.05). Two doses of L-Arg (10 and 50 nmol/150 nl) had no significant effect on ∆MAP or ∆HR. Higher dose of SNP (27 nmol) significantly decreased ∆MAP (P<0.05) and its both doses significantly decreased ∆HR compared to control (P<0.05 and P<0.001, respectively). Effect of higher dose on ∆HR was significantly higher than the lower dose (P<0.05). CONCLUSION Our results show an inhibitory effect of the nitrergic system of the PPT on central cardiovascular system.
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Affiliation(s)
- Mohammad Naser Shafei
- Neurogenic Inflammation Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Iran
| | - Tahereh Nikyar
- Department of Physiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mahmoud Hosseini
- Neurocognitive Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Saeed Niazmand
- Neurogenic Inflammation Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Iran
- Department of Physiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Maryam Paseban
- Department of Physiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
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8
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do Carmo JM, da Silva AA, Wang Z, Fang T, Aberdein N, Perez de Lara CE, Hall JE. Role of the brain melanocortins in blood pressure regulation. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2508-2514. [PMID: 28274841 DOI: 10.1016/j.bbadis.2017.03.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 02/27/2017] [Accepted: 03/02/2017] [Indexed: 10/20/2022]
Abstract
Melanocortins play an important role in regulating blood pressure (BP) and sympathetic nervous system (SNS) activity as well as energy balance, glucose and other metabolic functions in humans and experimental animals. In experimental models of hypertension with high SNS activity, blockade of the melanocortin-4 receptor (MC4R) reduces BP despite causing marked hyperphagia and obesity. Activation of the central nervous system (CNS) pro-opiomelanocortin (POMC)-MC4R pathway appears to be an important link between obesity, SNS activation and hypertension. Despite having severe obesity, subjects with MC4R deficiency exhibit reductions in BP, heart rate, and urinary catecholamine excretion, as well as attenuated SNS responses to cold stimuli compared to obese subjects with normal MC4R function. In this review we discuss the importance of the brain POMC-MC4R system in regulating SNS activity and BP in obesity and other forms of hypertension. We also highlight potential mechanisms and brain circuitry by which the melanocortin system regulates cardiovascular function.
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Affiliation(s)
- Jussara M do Carmo
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, MS, USA.
| | - Alexandre A da Silva
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, MS, USA; Barão de Mauá University Center, Ribeirão Preto, São Paulo, Brazil; Universidade Estadual de Minas Gerais, Passos, Minas Gerais, Brazil
| | - Zhen Wang
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, MS, USA
| | - Taolin Fang
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, MS, USA
| | - Nicola Aberdein
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, MS, USA
| | - Cecilia E Perez de Lara
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, MS, USA
| | - John E Hall
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, MS, USA
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Hill JW, Faulkner LD. The Role of the Melanocortin System in Metabolic Disease: New Developments and Advances. Neuroendocrinology 2017; 104:330-346. [PMID: 27728914 PMCID: PMC5724371 DOI: 10.1159/000450649] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 05/01/2016] [Indexed: 12/17/2022]
Abstract
Obesity is increasing in prevalence across all sectors of society, and with it a constellation of associated ailments including hypertension, type 2 diabetes, and eating disorders. The melanocortin system is a critical neural system underlying the control of body weight and other functions. Deficits in the melanocortin system may promote or exacerbate the comorbidities of obesity. This system has therefore generated great interest as a potential target for treatment of obesity. However, drugs targeting melanocortin receptors are plagued by problematic side effects, including undesirable increases in sympathetic nervous system activity, heart rate, and blood pressure. Circumnavigating this roadblock will require a clearer picture of the precise neural circuits that mediate the functions of melanocortins. Recent, novel experimental approaches have significantly advanced our understanding of these pathways. We here review the latest advances in our understanding of the role of melanocortins in food intake, reward pathways, blood pressure, glucose control, and energy expenditure. The evidence suggests that downstream melanocortin-responsive circuits responsible for different physiological actions do diverge. Ultimately, a more complete understanding of melanocortin pathways and their myriad roles should allow treatments tailored to the mix of metabolic disorders in the individual patient.
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Affiliation(s)
- Jennifer W Hill
- Department of Physiology and Pharmacology, College of Medicine, The University of Toledo, Toledo, OH, USA
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Central role for melanocortin-4 receptors in offspring hypertension arising from maternal obesity. Proc Natl Acad Sci U S A 2016; 113:12298-12303. [PMID: 27791019 DOI: 10.1073/pnas.1607464113] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Melanocortin-4 receptor (Mc4r)-expressing neurons in the autonomic nervous system, particularly in the paraventricular nucleus of the hypothalamus (PVH), play an essential role in blood pressure (BP) control. Mc4r-deficient (Mc4rKO) mice are severely obese but lack obesity-related hypertension; they also show a reduced pressor response to salt loading. We have previously reported that lean juvenile offspring born to diet-induced obese rats (OffOb) exhibit sympathetic-mediated hypertension, and we proposed a role for postnatally raised leptin in its etiology. Here, we test the hypothesis that neonatal hyperleptinemia due to maternal obesity induces persistent changes in the central melanocortin system, thereby contributing to offspring hypertension. Working on the OffOb paradigm in both sexes and using transgenic technology to restore Mc4r in the PVH of Mc4rKO (Mc4rPVH) mice, we have now shown that these mice develop higher BP than Mc4rKO or WT mice. We have also found that experimental hyperleptinemia induced in the neonatal period in Mc4rPVH and WT mice, but not in the Mc4rKO mice, leads to heightened BP and severe renal dysfunction. Thus, Mc4r in the PVH appears to be required for early-life programming of hypertension arising from either maternal obesity or neonatal hyperleptinemia. Early-life exposure of the PVH to maternal obesity through postnatal elevation of leptin may have long-term consequences for cardiovascular health.
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Muroi Y, Ishii T. A novel neuropeptide Y neuronal pathway linking energy state and reproductive behavior. Neuropeptides 2016; 59:1-8. [PMID: 27659234 DOI: 10.1016/j.npep.2016.09.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 09/08/2016] [Accepted: 09/08/2016] [Indexed: 01/12/2023]
Abstract
Animals consume energy for reproduction, as well as survival. Excess or insufficient energy investment into reproduction, respectively, threatens the survival of parents or leads to the failure of reproduction. Management of energy consumption in reproduction is important, not only for the success of the process, but also for the survival of the parents. Reproductive behaviors, such as mating and parental behavior, are indispensable for achieving each event of reproduction including gametogamy, parturition, and lactation. Therefore, reproductive behavior is one of the important factors in managing energy consumption for reproduction. Orexigenic and anorexigenic molecules in the hypothalamus have been implicated in the regulation of reproductive functions. An orexigenic neuropeptide, neuropeptide Y (NPY), has been also implicated in the regulation of both reproduction and energy state of animals. In this review, we will first summarize the neuronal mechanism for regulating reproductive functions by orexigenic and anorexigenic molecules in the hypothalamus. Second, we will focus on the NPY neuronal pathways regulating reproductive behavior in the intra- and extra-hypothalamic brain areas. We will highlight the NPY neuronal pathway from the arcuate nucleus to the dorsal raphe nucleus as a novel extra-hypothalamic pathway for energy state-dependent regulation of reproductive behavior. Finally, we will propose a biological significance of the extra-hypothalamic NPY neuronal pathway, which plays an important role in the associative control of feeding and reproductive behaviors.
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Affiliation(s)
- Yoshikage Muroi
- Department of Basic Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
| | - Toshiaki Ishii
- Department of Basic Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan
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da Silva AA, do Carmo JM, Wang Z, Hall JE. The brain melanocortin system, sympathetic control, and obesity hypertension. Physiology (Bethesda) 2015; 29:196-202. [PMID: 24789984 DOI: 10.1152/physiol.00061.2013] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Excess weight gain is the most significant, preventable cause of increased blood pressure (BP) in patients with primary (essential) hypertension and increases the risk for cardiovascular and renal diseases. In this review, we discuss the role of the brain melanocortin system in causing increased sympathetic activity in obesity and other forms of hypertension. In addition, we highlight potential mechanisms by which the brain melanocortin system modulates metabolic and cardiovascular functions.
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Affiliation(s)
- Alexandre A da Silva
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, and Cardiovascular-Renal Research Center, The University of Mississippi Medical Center, Jackson, Mississippi
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13
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Eerola K, Rinne P, Penttinen AM, Vähätalo L, Savontaus M, Savontaus E. α-MSH overexpression in the nucleus tractus solitarius decreases fat mass and elevates heart rate. J Endocrinol 2014; 222:123-36. [PMID: 24829220 DOI: 10.1530/joe-14-0064] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The POMC pathway is involved in the regulation of energy and cardiovascular homeostasis in the hypothalamus and the brain stem. Although the acute effects of POMC-derived peptides in different brain locations have been elucidated, the chronic site-specific effects of distinct peptides remain to be studied. To this end, we used a lentiviral gene delivery vector to study the long-term effects of α-MSH in the nucleus tractus solitarius (NTS) of the brain stem. The α-MSH vector (LVi-α-MSH-EGFP) based on the N-terminal POMC sequence and a control vector (LVi-EGFP) were delivered into the NTS of C57BL/6N male mice fed on a western diet. Effects on body weight and composition, feeding, glucose metabolism, and hemodynamics by telemetric analyses were studied during the 12-week follow-up. The LVi-α-MSH-EGFP-treated mice had a significantly smaller gain in the fat mass compared with LVi-EGFP-injected mice. There was a small initial decrease in food intake and no differences in the physical activity. Glucose metabolism was not changed compared with the control. LVi-α-MSH-EGFP increased the heart rate (HR), which was attenuated by adrenergic blockade suggesting an increased sympathetic activity. Reduced response to muscarinic blockade suggested a decreased parasympathetic activity. Fitting with sympathetic activation, LVi-α-MSH-EGFP treatment reduced urine secretion. Thus, the results demonstrate that long-term α-MSH overexpression in the NTS attenuates diet-induced obesity. Modulation of autonomic nervous system tone increased the HR and most probably contributed to an anti-obesity effect. The results underline the key role of NTS in the α-MSH-induced long-term effects on adiposity and in regulation of sympathetic and parasympathetic activities.
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Affiliation(s)
- K Eerola
- Department of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, FinlandDepartment of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, FinlandDepartment of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, Finland
| | - P Rinne
- Department of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, Finland
| | - A M Penttinen
- Department of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, Finland
| | - L Vähätalo
- Department of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, FinlandDepartment of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, Finland
| | - M Savontaus
- Department of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, FinlandDepartment of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, Finland
| | - E Savontaus
- Department of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, FinlandDepartment of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, Finland
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do Carmo JM, da Silva AA, Rushing JS, Pace B, Hall JE. Differential control of metabolic and cardiovascular functions by melanocortin-4 receptors in proopiomelanocortin neurons. Am J Physiol Regul Integr Comp Physiol 2013; 305:R359-68. [PMID: 23842677 DOI: 10.1152/ajpregu.00518.2012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We examined the role of melanocortin-4 receptors (MC4R) in proopiomelanocortin (Pomc) neurons in regulating metabolic and cardiovascular functions. Using Cre-loxP technology, we selectively rescued MC4R in Pomc neurons of mice with whole body MC4R deficiency (MC4R-Pomc-Cre mice). Body weight, food intake, and whole body oxygen consumption (Vo2) were determined daily, and blood pressure (BP), heart rate (HR), and body temperature were measured 24 h/day by telemetry. An intracerebroventricular cannula was placed in the right lateral ventricle for intracerebroventricular infusions. Littermate MC4R-deficient (LoxTB-MC4R) mice were used as controls. After control measurements, the MC4R antagonist (SHU-9119; 1 nmol/h) was infused intracerebroventricularly for 7 days. Compared with LoxTB-MC4R mice, MC4R-Pomc-Cre mice were less obese (47 ± 2 vs. 52 ± 2 g) and had increased energy expenditure (2,174 ± 98 vs. 1,990 ± 68 ml·kg⁻¹·min⁻¹), but food intake (4.4 ± 0.2 vs. 4.3 ± 0.3 g/day), BP (112 ± 1 vs. 109 ± 3 mmHg), and HR [557 ± 9 vs. 551 ± 14 beats per minute (bpm)] were similar between groups. Chronic SHU-9119 infusion increased food intake (4.2 ± 0.2 to 6.1 ± 0.5 g/day) and body weight (47 ± 2 to 52 ± 2 g) in MC4R-Pomc-Cre mice, while no changes were observed in LoxTB-MC4R mice. Chronic SHU-9119 infusion also increased BP and HR by 5 ± 1 mmHg and 60 ± 8 bpm in MC4R-Pomc-Cre mice without altering BP or HR in LoxTB-MC4R mice. These results indicate that MC4Rs in Pomc neurons are important for regulation of energy balance. In contrast, while activation of MC4R in Pomc neurons facilitates the BP response to acute stress, our data do not support a major role of MC4R in Pomc neurons in regulating baseline BP and HR.
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Affiliation(s)
- Jussara M do Carmo
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
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Rinne P, Harjunpää J, Mäkelä S, Savontaus E. Genetic and pharmacological mouse models of chronic melanocortin activation show enhanced baroreflex control of heart rate. ACTA ACUST UNITED AC 2013; 182:19-27. [DOI: 10.1016/j.regpep.2012.12.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 09/05/2012] [Accepted: 12/17/2012] [Indexed: 10/27/2022]
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do Carmo JM, da Silva AA, Rushing JS, Hall JE. Activation of the central melanocortin system contributes to the increased arterial pressure in obese Zucker rats. Am J Physiol Regul Integr Comp Physiol 2011; 302:R561-7. [PMID: 22204957 DOI: 10.1152/ajpregu.00392.2011] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have previously demonstrated that leptin-mediated activation of the central nervous system (CNS) melanocortin system reduces appetite and increases sympathetic activity and blood pressure (BP). In the present study we examined whether endogenous melanocortin system activation, independent of leptin's actions, contributes to the regulation of BP and metabolic functions in obese Zucker rats, which have mutated leptin receptors. The long-term cardiovascular and metabolic effects of central melanocortin-3/4 receptor (MC3/4R) antagonism with SHU-9119 were assessed in lean (n = 6) and obese (n = 8) Zucker rats. BP and heart rate (HR) were measured 24-h/day by telemetry and an intracerebroventricular cannula was placed in the brain lateral ventricle. After stable control measurements, SHU-9119 was infused intracerebroventricularlly (1 nmol/h) for 10 days followed by a 10-day recovery period. Chronic CNS MC3/4R antagonism significantly increased food intake and body weight in lean (20 ± 1 to 45 ± 2 g and 373 ± 11 to 432 ± 14 g) and obese (25 ± 2 to 35 ± 2 g and 547 ± 10 to 604 ± 11 g) rats. No significant changes were observed in plasma glucose levels in lean or obese rats, whereas plasma leptin and insulin levels markedly increased in lean Zucker rats during CNS MC3/4R antagonism. Chronic SHU-9119 infusion in obese Zucker rats reduced mean arterial pressure (MAP) and HR by 6 ± 1 mmHg and 24 ± 5 beats/min, whereas in lean rats SHU-9119 infusion reduced HR by 31 ± 9 beats/min while causing only a transient decrease in MAP. These results suggest that in obese Zucker rats the CNS melanocortin system contributes to elevated BP independent of leptin receptor activation.
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Affiliation(s)
- Jussara M do Carmo
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS 39216-4505, USA.
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Yen DHT, Chen LC, Shen YC, Chiu YC, Ho IC, Lou YJ, Chen IC, Yen JC. Protein kinase A-dependent neuronal nitric oxide synthase activation mediates the enhancement of baroreflex response by adrenomedullin in the nucleus tractus solitarii of rats. J Biomed Sci 2011; 18:32. [PMID: 21595896 PMCID: PMC3115842 DOI: 10.1186/1423-0127-18-32] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 05/19/2011] [Indexed: 11/10/2022] Open
Abstract
Background Adrenomedullin (ADM) exerts its biological functions through the receptor-mediated enzymatic mechanisms that involve protein kinase A (PKA), or neuronal nitric oxide synthase (nNOS). We previously demonstrated that the receptor-mediated cAMP/PKA pathway involves in ADM-enhanced baroreceptor reflex (BRR) response. It remains unclear whether ADM may enhance BRR response via activation of nNOS-dependent mechanism in the nucleus tractus solitarii (NTS). Methods Intravenous injection of phenylephrine was administered to evoke the BRR before and at 10, 30, and 60 min after microinjection of the test agents into NTS of Sprague-Dawley rats. Western blotting analysis was used to measure the level and phosphorylation of proteins that involved in BRR-enhancing effects of ADM (0.2 pmol) in NTS. The colocalization of PKA and nNOS was examined by immunohistochemical staining and observed with a laser confocal microscope. Results We found that ADM-induced enhancement of BRR response was blunted by microinjection of NPLA or Rp-8-Br-cGMP, a selective inhibitor of nNOS or protein kinase G (PKG) respectively, into NTS. Western blot analysis further revealed that ADM induced an increase in the protein level of PKG-I which could be attenuated by co-microinjection with the ADM receptor antagonist ADM22-52 or NPLA. Moreover, we observed an increase in phosphorylation at Ser1416 of nNOS at 10, 30, and 60 min after intra-NTS administration of ADM. As such, nNOS/PKG signaling may also account for the enhancing effect of ADM on BRR response. Interestingly, biochemical evidence further showed that ADM-induced increase of nNOS phosphorylation was prevented by co-microinjection with Rp-8-Br-cAMP, a PKA inhibitor. The possibility of PKA-dependent nNOS activation was substantiated by immunohistochemical demonstration of co-localization of PKA and nNOS in putative NTS neurons. Conclusions The novel finding of this study is that the signal transduction cascade that underlies the enhancement of BRR response by ADM in NTS is composed sequentially of cAMP/PKA and nNOS/PKG pathways.
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Affiliation(s)
- David H T Yen
- Institute of Emergency and Critical Care Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan
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Miozza V, Borda E, S-Borda L, Busch L. Increase nitric oxide synthase activity in parotid glands from rats with experimental periodontitis. Oral Dis 2010; 16:801-6. [DOI: 10.1111/j.1601-0825.2010.01691.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Shariat-Madar B, Kolte D, Verlangieri A, Shariat-Madar Z. Prolylcarboxypeptidase (PRCP) as a new target for obesity treatment. Diabetes Metab Syndr Obes 2010; 3:67-78. [PMID: 20694162 PMCID: PMC2916657 DOI: 10.2147/dmsott.s7290] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Recently, we serendipitously discovered that mice with the deficiency of the enzyme prolylcarboxypeptidase (PRCP) have elevated alpha-melanocyte-stimulating hormone (alpha-MSH) levels which lead to decreased food intake and weight loss. This suggests that PRCP is an endogenous inactivator of alpha-MSH and an appetite stimulant. Since a modest weight loss can have the most profound influence on reducing cardiovascular risk factors, the inhibitors of PRCP would be emerging as a possible alternative for pharmacotherapy in high-risk patients with obesity and obesity-related disorders. The discovery of a new biological activity of PRCP in the PRCP-deficient mice and studies of alpha-MSH function indicate the importance and complexity of the hypothalamic pro-opiomelanocortin (POMC) system in altering food intake. Identifying a role for PRCP in regulating alpha-MSH in the brain may be a critical step in enhancing our understanding of how the brain controls food intake and body weight. In light of recent findings, the potential role of PRCP in regulating fuel homeostasis is critically evaluated. Further studies of the role of PRCP in obesity are much needed.
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Affiliation(s)
- B Shariat-Madar
- College of Literature, Science, and the Arts, University of Michigan, Ann Arbor MI, USA
| | - D Kolte
- School of Pharmacy, Department of Pharmacology, University of Mississippi, University, MS, USA
| | - A Verlangieri
- School of Pharmacy, Department of Pharmacology, University of Mississippi, University, MS, USA
| | - Z Shariat-Madar
- School of Pharmacy, Department of Pharmacology, University of Mississippi, University, MS, USA
- Correspondence: Zia Shariat-Madar, University of Mississippi, 219 B, Faser Hall, University, MS 38677–1848, USA, Tel +662 915 5150, Fax +662 915 5148, Email
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Cheng WH, Lu PJ, Ho WY, Tung CS, Cheng PW, Hsiao M, Tseng CJ. Angiotensin II Inhibits Neuronal Nitric Oxide Synthase Activation Through the ERK1/2-RSK Signaling Pathway to Modulate Central Control of Blood Pressure. Circ Res 2010; 106:788-95. [DOI: 10.1161/circresaha.109.208439] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Rationale
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Angiotensin (Ang) II exerts diverse physiological actions in both the peripheral and central neural systems. It was reported that the activity of Ang II is higher in the nucleus tractus solitarii (NTS) of spontaneously hypertensive rats (SHRs) and that angiotensin type-1 receptors are colocalized with NAD(P)H oxidase in the neurons of the NTS, resulting in the induction of local reactive oxygen species production by Ang II. However, the signaling mechanisms of Ang II that induce hypertension remain unclear.
Objective
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The aim of this study was to investigate the possible signaling pathways involved in Ang II–mediated blood pressure regulation in the NTS.
Methods and Results
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Male SHRs were treated with losartan or tempol for 2 weeks, after which systolic blood pressure was observed to decrease significantly. Dihydroethidium staining showed many cells with high reactive oxygen species in the NTS of SHRs. The addition of losartan or tempol decreased the numbers of reactive oxygen species–positive cells in the NTS. The systemic administration of losartan or tempol reduced the systolic blood pressure and increased NO production. Immunoblotting and immunohistochemical analysis further showed that inhibition of Ang II activity by losartan or tempol significantly increased the expression extracellular signal-regulated kinase (ERK)1/2, ribosomal protein S6 kinase (RSK), and also increased neuronal NO synthase (nNOS) phosphorylation. RSK was also found to bind directly to nNOS and induce phosphorylation at the Ser1416 position.
Conclusions
:
Taken together, these results suggest that the ERK1/2-RSK-nNOS signaling pathway may play a significant role in Ang II–mediated central blood pressure regulation.
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Affiliation(s)
- Wen-Han Cheng
- From the Department of Medical Education and Research (W.-H.C., P.-W.C., C.-J.T.), Kaohsiung Veterans General Hospital, Kaohsiung; Institute of Clinical Medicine (W.-H.C., C.-J.T.), National Yang-Ming University, Taipei; Institute of Biomedical Sciences (W.-H.C., C.-J.T.), National Sun Yat-sen University, Kaohsiung; Institute of Clinical Medicine (P.-J.L.), National Cheng-Kung University, Tainan; Department of Internal Medicine (W.-Y.H.), Zuoying Armed Forces General Hospital, Kaohsiung; Department
| | - Pei-Jung Lu
- From the Department of Medical Education and Research (W.-H.C., P.-W.C., C.-J.T.), Kaohsiung Veterans General Hospital, Kaohsiung; Institute of Clinical Medicine (W.-H.C., C.-J.T.), National Yang-Ming University, Taipei; Institute of Biomedical Sciences (W.-H.C., C.-J.T.), National Sun Yat-sen University, Kaohsiung; Institute of Clinical Medicine (P.-J.L.), National Cheng-Kung University, Tainan; Department of Internal Medicine (W.-Y.H.), Zuoying Armed Forces General Hospital, Kaohsiung; Department
| | - Wen-Yu Ho
- From the Department of Medical Education and Research (W.-H.C., P.-W.C., C.-J.T.), Kaohsiung Veterans General Hospital, Kaohsiung; Institute of Clinical Medicine (W.-H.C., C.-J.T.), National Yang-Ming University, Taipei; Institute of Biomedical Sciences (W.-H.C., C.-J.T.), National Sun Yat-sen University, Kaohsiung; Institute of Clinical Medicine (P.-J.L.), National Cheng-Kung University, Tainan; Department of Internal Medicine (W.-Y.H.), Zuoying Armed Forces General Hospital, Kaohsiung; Department
| | - Che-Se Tung
- From the Department of Medical Education and Research (W.-H.C., P.-W.C., C.-J.T.), Kaohsiung Veterans General Hospital, Kaohsiung; Institute of Clinical Medicine (W.-H.C., C.-J.T.), National Yang-Ming University, Taipei; Institute of Biomedical Sciences (W.-H.C., C.-J.T.), National Sun Yat-sen University, Kaohsiung; Institute of Clinical Medicine (P.-J.L.), National Cheng-Kung University, Tainan; Department of Internal Medicine (W.-Y.H.), Zuoying Armed Forces General Hospital, Kaohsiung; Department
| | - Pei-Wen Cheng
- From the Department of Medical Education and Research (W.-H.C., P.-W.C., C.-J.T.), Kaohsiung Veterans General Hospital, Kaohsiung; Institute of Clinical Medicine (W.-H.C., C.-J.T.), National Yang-Ming University, Taipei; Institute of Biomedical Sciences (W.-H.C., C.-J.T.), National Sun Yat-sen University, Kaohsiung; Institute of Clinical Medicine (P.-J.L.), National Cheng-Kung University, Tainan; Department of Internal Medicine (W.-Y.H.), Zuoying Armed Forces General Hospital, Kaohsiung; Department
| | - Michael Hsiao
- From the Department of Medical Education and Research (W.-H.C., P.-W.C., C.-J.T.), Kaohsiung Veterans General Hospital, Kaohsiung; Institute of Clinical Medicine (W.-H.C., C.-J.T.), National Yang-Ming University, Taipei; Institute of Biomedical Sciences (W.-H.C., C.-J.T.), National Sun Yat-sen University, Kaohsiung; Institute of Clinical Medicine (P.-J.L.), National Cheng-Kung University, Tainan; Department of Internal Medicine (W.-Y.H.), Zuoying Armed Forces General Hospital, Kaohsiung; Department
| | - Ching-Jiunn Tseng
- From the Department of Medical Education and Research (W.-H.C., P.-W.C., C.-J.T.), Kaohsiung Veterans General Hospital, Kaohsiung; Institute of Clinical Medicine (W.-H.C., C.-J.T.), National Yang-Ming University, Taipei; Institute of Biomedical Sciences (W.-H.C., C.-J.T.), National Sun Yat-sen University, Kaohsiung; Institute of Clinical Medicine (P.-J.L.), National Cheng-Kung University, Tainan; Department of Internal Medicine (W.-Y.H.), Zuoying Armed Forces General Hospital, Kaohsiung; Department
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da Silva AA, do Carmo JM, Kanyicska B, Dubinion J, Brandon E, Hall JE. Endogenous melanocortin system activity contributes to the elevated arterial pressure in spontaneously hypertensive rats. Hypertension 2008; 51:884-90. [PMID: 18285617 DOI: 10.1161/hypertensionaha.107.100636] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Previous studies suggest that activation of the CNS melanocortin system reduces appetite while increasing sympathetic activity and arterial pressure. The present study tested whether endogenous activity of the CNS melanocortin 3/4 receptors (MC3/4-R) contributes to elevated arterial pressure in the spontaneously hypertensive rat (SHR), a model of hypertension with increased sympathetic activity. A cannula was placed in the lateral ventricle of male SHR and Wistar (WKY) rats for chronic intracerebroventricular (ICV) infusions (0.5 muL/h). Mean arterial pressure (MAP) and heart rate (HR) were recorded 24 hour/d using telemetry. After 5-day control period, rats were infused with MC3/4-R antagonist (SHU-9119, 1 nmol/h-ICV) for 12 days, followed by 5-day posttreatment period. MC3/4-R antagonism increased food intake in SHR by 90% and in WKY by 125%, resulting in marked weight gain, insulin resistance, and hyperleptinemia in SHR and WKY. Despite weight gain, MC3/4-R antagonism reduced HR in SHR and WKY ( approximately 40 bpm), while lowering MAP to a greater extent in SHR (-22+/-4 mm Hg) than WKY (-4+/-3 mm Hg). SHU9119 treatment failed to cause further reductions in MAP during chronic adrenergic blockade with propranolol and terazosin. These results suggest that endogenous activity of the CNS melanocortin system contributes to the maintenance of adrenergic tone and elevated arterial pressure in SHR even though mRNA levels for POMC and MC4R in the mediobasal hypothalamus were not increased compared to WKY. These results also support the hypothesis that weight gain does not raise arterial pressure in the absence of a functional MC3/4-R.
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Affiliation(s)
- Alexandre A da Silva
- Department of Physiology and Biophysics, University of Mississippi Medical Center, 2500 North State St, Jackson, MS 39216-4505, USA.
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Legros E, Tirapelli CR, Carrier E, Brochu I, Fournier A, D'Orléans-Juste P. Characterization of the non-adrenergic/non-cholinergic response to perivascular nerve stimulation in the double-perfused mesenteric bed of the mouse. Br J Pharmacol 2007; 152:1049-59. [PMID: 17906682 PMCID: PMC2095099 DOI: 10.1038/sj.bjp.0707475] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE Calcitonin gene-related peptide (CGRP), a capsaicin-sensitive neuromodulator of splanchnic vascular tone in several animal species, remains poorly investigated in mouse models. We therefore assessed whether endogenous CGRP is a non-adrenergic/non-cholinergic (NANC) neuromodulator in the mesenteric vascular bed of the mouse. EXPERIMENTAL APPROACH Arterial and venous changes in perfusion pressure in response to perivascular nerve stimulation (PNS) were monitored in the mouse mesenteric bed under basal conditions or precontracted with KCl (artery) or U46619 (vein) in circuits pretreated with guanethidine, atropine, indomethacin and prazosin. Arterial responses to NANC were also characterized with a CGRP1 antagonist, halphaCGRP8-37. Finally, the PNS-induced release of arterial CGRP was measured by enzyme immunoassay. KEY RESULTS HalphaCGRP8-37 enhanced PNS-induced arterial increases in perfusion pressure under basal tone. PNS-induced stimulation of NANC triggered an halphaCGRP8-37 or capsaicin- sensitive reduction in perfusion pressure of the pre-contracted arterial bed only. Chemical removal of the endothelium inhibited PNS- and halphaCGRP- induced reduction in perfusion pressure in the arterial mesenteric bed. Responses to NANC nerves were reduced by guanylate and adenylate cyclase inhibitors (1H-[1,2,4]oxadiazole[4,3-a] quinoxalin-1-one (ODQ)) and [9-(tetrahydro-2-furanyl)-9H-purin-6-amine] (SQ 22,536), respectively. A neuronal NOS inhibitor (7-nitroindazole; 7-NI) also enhanced the response to NANC in vessels from wild-type, eNOS KO but not iNOS KO mice. Finally, PNS enhanced the release of immunoreactive CGRP from the perfused arterial mesenteric bed. CONCLUSIONS AND IMPLICATIONS Our study demonstrates a role for CGRP in the NANC-dependent reduction in perfusion pressure of the arterial but not venous mesenteric bed of the mouse.
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Affiliation(s)
- E Legros
- Department of Pharmacology, Medical School, Institut de pharmacologie de Sherbrooke, Université de Sherbrooke Sherbrooke, Québec, Canada
| | - C R Tirapelli
- Department of Psychiatry Nursing and Human Sciences, College of Nursing of Ribeirao Preto, University of Sao Paulo (USP) Ribeirao Preto, Brazil
| | - E Carrier
- Department of Pharmacology, Medical School, Institut de pharmacologie de Sherbrooke, Université de Sherbrooke Sherbrooke, Québec, Canada
| | - I Brochu
- Department of Pharmacology, Medical School, Institut de pharmacologie de Sherbrooke, Université de Sherbrooke Sherbrooke, Québec, Canada
| | - A Fournier
- INRS-Institut Armand-Frappier, Institut national de la recherche scientifique, Université du Québec, Laboratoire d'études moléculaires et, pharmacologiques des peptides Pointe-Claire (Montréal), Québec, Canada
| | - P D'Orléans-Juste
- Department of Pharmacology, Medical School, Institut de pharmacologie de Sherbrooke, Université de Sherbrooke Sherbrooke, Québec, Canada
- Author for correspondence:
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