1
|
Savić B, Murphy D, Japundžić-Žigon N. The Paraventricular Nucleus of the Hypothalamus in Control of Blood Pressure and Blood Pressure Variability. Front Physiol 2022; 13:858941. [PMID: 35370790 PMCID: PMC8966844 DOI: 10.3389/fphys.2022.858941] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 02/15/2022] [Indexed: 12/26/2022] Open
Abstract
The paraventricular nucleus (PVN) is a highly organized structure of the hypothalamus that has a key role in regulating cardiovascular and osmotic homeostasis. Functionally, the PVN is divided into autonomic and neuroendocrine (neurosecretory) compartments, both equally important for maintaining blood pressure (BP) and body fluids in the physiological range. Neurosecretory magnocellular neurons (MCNs) of the PVN are the main source of the hormones vasopressin (VP), responsible for water conservation and hydromineral balance, and oxytocin (OT), involved in parturition and milk ejection during lactation. Further, neurosecretory parvocellular neurons (PCNs) take part in modulation of the hypothalamic–pituitary–adrenal axis and stress responses. Additionally, the PVN takes central place in autonomic adjustment of BP to environmental challenges and contributes to its variability (BPV), underpinning the PVN as an autonomic master controller of cardiovascular function. Autonomic PCNs of the PVN modulate sympathetic outflow toward heart, blood vessels and kidneys. These pre-autonomic neurons send projections to the vasomotor nucleus of rostral ventrolateral medulla and to intermediolateral column of the spinal cord, where postganglionic fibers toward target organs arise. Also, PVN PCNs synapse with NTS neurons which are the end-point of baroreceptor primary afferents, thus, enabling the PVN to modify the function of baroreflex. Neuroendocrine and autonomic parts of the PVN are segregated morphologically but they work in concert when the organism is exposed to environmental challenges via somatodendritically released VP and OT by MCNs. The purpose of this overview is to address both neuroendocrine and autonomic PVN roles in BP and BPV regulation.
Collapse
Affiliation(s)
- Bojana Savić
- Laboratory for Cardiovascular Pharmacology and Toxicology, Faculty of Medicine, Institute of Pharmacology, Clinical Pharmacology and Toxicology, University of Belgrade, Belgrade, Serbia
| | - David Murphy
- Molecular Neuroendocrinology Research Group, Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol, United Kingdom
| | - Nina Japundžić-Žigon
- Laboratory for Cardiovascular Pharmacology and Toxicology, Faculty of Medicine, Institute of Pharmacology, Clinical Pharmacology and Toxicology, University of Belgrade, Belgrade, Serbia
- *Correspondence: Nina Japundžić-Žigon,
| |
Collapse
|
2
|
Phenomapping for classification of doxorubicin-induced cardiomyopathy in rats. Toxicol Appl Pharmacol 2021; 423:115579. [PMID: 34015281 DOI: 10.1016/j.taap.2021.115579] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 04/22/2021] [Accepted: 05/13/2021] [Indexed: 12/20/2022]
Abstract
Cardiomyopathy resistant to treatment is the most serious adverse effect of doxorubicin (dox). The mechanisms of dox-induced cardiomyopathy (DCM) have been extensively studied in dilated forms of DCM. However, efficient treatment did not emerge. The aim of the present work was to revisit the experimental model of DCM in rats, to define phenotype/s and associate them to the changes in cardiac transcriptome. Male Wistar rats equipped with radiotelemetry device, were randomized in DOX group (5 mg/0,5 mL/kg, IV dox; n = 18) and CONT group (0,5 mL/kg IV saline; n = 6). Echocardiography, autonomic spectral markers and baroreceptor reflex evaluation was performed prior to, and after treatment. Blood samples were collected at the end of experimentation. Cardiac, renal and hepatic tissues were analysed post-mortem by histology. Changes in expression of key cardiac genes affected by dox were assessed by RT-qPCR. Phenotypes were identified by clustering non-redundant features using four different algorithms averaged by evidence accumulation cluster technique. The results emphasize the existence of two major phenotypes of DCM with comparably high mortality rates: phenotype 1 characterized by, left ventricular (LV) dilatation, thinning of LV posterior wall, reduced LV ejection fraction (LVEF) and fractional shortening (LVFS), decreased HR variability (HRV), decreased baroreceptor effectiveness index (BEI) and increased NT-proBNP; and phenotype 2 with LV hypertrophy - increased LV mass, preserved LVEF, LVFS, no changes in HRV and BEI and moderate NT-proBNP increase. Both phenotypes exhibited a genetic shift to a new-born program.
Collapse
|
3
|
Martin A, Mecawi AS, Antunes VR, Yao ST, Antunes-Rodrigues J, Paton JFR, Paterson A, Greenwood M, Šarenac O, Savić B, Japundžić-Žigon N, Murphy D, Hindmarch CCT. Transcriptome Analysis Reveals Downregulation of Urocortin Expression in the Hypothalamo-Neurohypophysial System of Spontaneously Hypertensive Rats. Front Physiol 2021; 11:599507. [PMID: 33815127 PMCID: PMC8011454 DOI: 10.3389/fphys.2020.599507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 10/22/2020] [Indexed: 11/21/2022] Open
Abstract
The chronically increased blood pressure characteristic of essential hypertension represents an insidious and cumulative risk for cardiovascular disease. Essential hypertension is a multifactorial condition, with no known specific aetiology but a strong genetic component. The Spontaneously Hypertensive rat (SHR) shares many characteristics of human essential hypertension, and as such is a commonly used experimental model. The mammalian hypothalamo-neurohypophyseal system (HNS) plays a pivotal role in the regulation of blood pressure, volume and osmolality. In order to better understand the possible role of the HNS in hypertension, we have used microarray analysis to reveal differential regulation of genes in the HNS of the SHR compared to a control normotensive strain, the Wistar Kyoto rat (WKY). These results were validated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). One of the genes identified and validated as being downregulated in SHR compared to WKY was that encoding the neuropeptide urocortin (Ucn). Immunohistochemical analyses revealed Ucn to be highly expressed within magnocellular neurons of the PVN and SON, with pronounced localisation in dendritic projections containing oxytocin and vasopressin. When Ucn was overexpressed in the PVN of the SHR by in vivo lentiviral mediated gene transfer, blood pressure was unaffected but there were significant, transient reductions in the VLF spectra of systolic blood pressure consistent with an action on autonomic balance. We suggest that Ucn may act, possibly via dendritic release, to subtly regulate neurohumoral aspects of arterial pressure control.
Collapse
Affiliation(s)
- Andrew Martin
- Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, United Kingdom
| | - Andre S Mecawi
- Laboratory of Neuroendocrinology, Department of Biophysics, Paulista School of Medicine, Federal University of São Paulo, São Paulo, Brazil
| | - Vagner R Antunes
- Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, United Kingdom.,Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Song T Yao
- Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, United Kingdom.,Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - Jose Antunes-Rodrigues
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Julian F R Paton
- Manaaki Mānawa, The Heart Research Centre, University of Auckland, Auckland, New Zealand
| | - Alex Paterson
- Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, United Kingdom
| | - Michael Greenwood
- Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, United Kingdom
| | - Olivera Šarenac
- Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, United Kingdom.,Faculty of Medicine, Institute of Pharmacology, Clinical Pharmacology and Toxicology, University of Belgrade, Belgrade, Serbia
| | - Bojana Savić
- Faculty of Medicine, Institute of Pharmacology, Clinical Pharmacology and Toxicology, University of Belgrade, Belgrade, Serbia
| | - Nina Japundžić-Žigon
- Faculty of Medicine, Institute of Pharmacology, Clinical Pharmacology and Toxicology, University of Belgrade, Belgrade, Serbia
| | - David Murphy
- Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, United Kingdom
| | - Charles C T Hindmarch
- Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, United Kingdom.,Queen's Cardiopulmonary Unit, Department of Medicine, Translational Institute of Medicine, Queen's University, Kingston, ON, Canada
| |
Collapse
|
4
|
Japundžić-Žigon N, Lozić M, Šarenac O, Murphy D. Vasopressin & Oxytocin in Control of the Cardiovascular System: An Updated Review. Curr Neuropharmacol 2020; 18:14-33. [PMID: 31544693 PMCID: PMC7327933 DOI: 10.2174/1570159x17666190717150501] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 06/03/2019] [Accepted: 07/06/2019] [Indexed: 01/19/2023] Open
Abstract
Since the discovery of vasopressin (VP) and oxytocin (OT) in 1953, considerable knowledge has been gathered about their roles in cardiovascular homeostasis. Unraveling VP vasoconstrictor properties and V1a receptors in blood vessels generated powerful hemostatic drugs and drugs effective in the treatment of certain forms of circulatory collapse (shock). Recognition of the key role of VP in water balance via renal V2 receptors gave birth to aquaretic drugs found to be useful in advanced stages of congestive heart failure. There are still unexplored actions of VP and OT on the cardiovascular system, both at the periphery and in the brain that may open new venues in treatment of cardiovascular diseases. After a brief overview on VP, OT and their peripheral action on the cardiovascular system, this review focuses on newly discovered hypothalamic mechanisms involved in neurogenic control of the circulation in stress and disease.
Collapse
Affiliation(s)
| | - Maja Lozić
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Olivera Šarenac
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - David Murphy
- School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| |
Collapse
|
5
|
Kasum O, Perović A, Jovanović A. Measures and Metrics of Biological Signals. Front Physiol 2018; 9:1707. [PMID: 30564137 PMCID: PMC6288820 DOI: 10.3389/fphys.2018.01707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 11/13/2018] [Indexed: 11/13/2022] Open
Abstract
The concept of biological signals is becoming broader. Some of the challenges are: searching for inner and structural characteristics; selecting appropriate modeling to enhance perceived properties in the signals; extracting the representative components, identifying their mathematical correspondents; and performing necessary transformations in order to obtain form for subtle analysis, comparisons, derived recognition, and classification. There is that unique moment when we correspond the adequate mathematical structures to the observed phenomena. It allows application of various mathematical constructs, transformations and reconstructions. Finally, comparisons and classifications of the newly observed phenomena often lead to enrichment of the existing models with some additional structurality. For a specialized context the modeling takes place in a suitable set of mathematical representations of the same kind, a set of models M, where the mentioned transformations take place. They are used for determination of structures M, where mathematical finalization processes are preformed. Normalized representations of the initial content are measured in order to determine the key invariants (characterizing characteristics). Then, comparisons are preformed for specialized or targeted purposes. The process converges to the measures and distance measurements in the space M. Thus, we are dealing with measure and metric spaces, gaining opportunities that have not been initially available. Obviously, the different aspects in the research or diagnostics will demand specific spaces. In our practice we faced a large variety of problems in analysis of biological signals with very rich palette of measures and metrics. Even when a unique phenomena are observed for slightly different aspects of their characteristics, the corresponding measurements differ, or are refinements of the initial structures. Certain criteria need to be fulfilled. Namely, characterization and semantic stability. The small changes in the structures have to induce the small changes in measures and metrics. We offer a collection of the models that we have been involved in, together with the problems we met and their solutions, with representative visualizations.
Collapse
Affiliation(s)
- Obrad Kasum
- Group for Intelligent Systems (GIS), Faculty of Mathematics, University of Belgrade, Belgrade, Serbia
| | - Aleksandar Perović
- Group for Intelligent Systems (GIS), Faculty of Mathematics, University of Belgrade, Belgrade, Serbia.,Faculty of Transport and Traffic Engineering, University of Belgrade, Belgrade, Serbia
| | - Aleksandar Jovanović
- Group for Intelligent Systems (GIS), Faculty of Mathematics, University of Belgrade, Belgrade, Serbia
| |
Collapse
|
6
|
Tasić T, Djordjević DM, De Luka SR, Trbovich AM, Japundžić-Žigon N. Static magnetic field reduces blood pressure short-term variability and enhances baro-receptor reflex sensitivity in spontaneously hypertensive rats. Int J Radiat Biol 2017; 93:527-534. [PMID: 28051886 DOI: 10.1080/09553002.2017.1276307] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
PURPOSE It has been shown that chronic exposure of young spontaneously hypertensive rats (SHR) to static magnetic field (SMF) delays the development of overt hypertension. Therefore the aim of the present work was to investigate the effects of SMF on autonomic cardiovascular control in adult spontaneously hypertensive rats. MATERIALS AND METHODS Experiments were performed in freely moving spontaneously hypertensive rats equipped with femoral arterial catheter for blood pressure recording. Spontaneously hypertensive rats were exposed for 30 days to upward-oriented SMF (n = 17) or downward-oriented SMF (n = 17) of 16 mT intensity. A control group of spontaneously hypertensive rats (n = 17) was not exposed to SMF. Neurogenic cardiovascular control was evaluated by spectral analysis of arterial blood pressure and heart rate short-term variability and baro-receptor reflex sensitivity using the sequence method. RESULTS Exposure of spontaneously hypertensive rats to both upward- and downward-oriented SMF significantly reduced arterial blood pressure and enhanced baro-receptor reflex sensitivity. Downward-oriented SMF reduced heart rate, too. SMF of either orientation reduced systolic blood pressure variability in very low frequency domain while downward-oriented SMF also reduced low-frequency and increased high frequency domains. CONCLUSION It follows that prolonged exposure to SMF is beneficial for neurogenic cardiovascular control in hypertension.
Collapse
Affiliation(s)
- Tatjana Tasić
- a Institute of Pharmacology , Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade , Belgrade , Serbia
| | - Drago M Djordjević
- b Institute of Pathophysiology , Faculty of Medicine, University of Belgrade , Belgrade , Serbia
| | - Silvio R De Luka
- b Institute of Pathophysiology , Faculty of Medicine, University of Belgrade , Belgrade , Serbia
| | - Alexander M Trbovich
- b Institute of Pathophysiology , Faculty of Medicine, University of Belgrade , Belgrade , Serbia
| | - Nina Japundžić-Žigon
- a Institute of Pharmacology , Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade , Belgrade , Serbia
| |
Collapse
|
7
|
Japundžić-Žigon N. Vasopressin and oxytocin in control of the cardiovascular system. Curr Neuropharmacol 2013; 11:218-30. [PMID: 23997756 PMCID: PMC3637675 DOI: 10.2174/1570159x11311020008] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 11/01/2012] [Accepted: 12/03/2012] [Indexed: 12/31/2022] Open
Abstract
Vasopressin (VP) and oxytocin (OT) are mainly synthesized in the magnocellular neurons of the paraventricular (PVN) and supraoptic nucleus (SON) of the hypothalamus. Axons from the magnocellular part of the PVN and SON project to neurohypophysis where VP and OT are released in blood to act like hormones. Axons from the parvocellular part of PVN project to extra-hypothalamic brain areas (median eminence, limbic system, brainstem and spinal cord) where VP and OT act like neurotransmitters/modulators. VP and OT act in complementary manner in cardiovascular control, both as hormones and neurotransmitters. While VP conserves water and increases circulating blood volume, OT eliminates sodium. Hyperactivity of VP neurons and quiescence of OT neurons in PVN underlie osmotic adjustment to pregnancy. In most vascular beds VP is a potent vasoconstrictor, more potent than OT, except in the umbilical artery at term. The vasoconstriction by VP and OT is mediated via V1aR. In some vascular beds, i.e. the lungs and the brain, VP and OT produce NO dependent vasodilatation. Peripherally, VP has been found to enhance the sensitivity of the baro-receptor while centrally, VP and OT increase sympathetic outflow, suppresse baro-receptor reflex and enhance respiration. Whilst VP is an important mediator of stress that triggers ACTH release, OT exhibits anti-stress properties. Moreover, VP has been found to contribute considerably to progression of hypertension and heart failure while OT has been found to decrease blood pressure and promote cardiac healing.
Collapse
Affiliation(s)
- Nina Japundžić-Žigon
- Professor of Basic and Clinical Pharmacology and Toxicology, University of Belgrade School of Medicine, Institute of Pharmacology, Clinical Pharmacology and Toxicology, Dr Subotica 1, Belgrade, Republic of Serbia
| |
Collapse
|
8
|
Hagedorn TM, Carlin RW, Schultz BD. Oxytocin and vasopressin stimulate anion secretion by human and porcine vas deferens epithelia. Biol Reprod 2007; 77:416-24. [PMID: 17442854 DOI: 10.1095/biolreprod.106.056762] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Experiments were conducted to characterize the effects of oxytocin (OT) and vasopressin (VP) on epithelial cells isolated from human (1 degree HVD) and porcine (1 degree PVD) vas deferens and an immortalized epithelial cell line derived from porcine vas deferens (PVD9902 cells). Cultured monolayers were assessed in modified Ussing flux chambers and the OT- or VP-induced change in short circuit current (I(SC)) was recorded. All cell types responded to basolateral OT or VP with a transient increase in I(SC) that reached a peak of 3-5 microA cm(-2). Concentration-response curves constructed with 1 degree PVD and PVD9902 cells revealed that the apparent K(D) (k(app)) for OT was approximately 100-fold less than the k(app) for VP. Amplicons for the OT receptor (OXTR) and vasopressin type 2 and type 1a receptors (AVPR2 and AVPR1A) were generated with RT-PCR and the identification of each amplicon confirmed by sequence analysis. A selective antagonist for OXTR and AVPR1A fully blocked the effects of OT and partially blocked the effects of VP when assessed in both 1 degree PVD and PVD9902 monolayers. APVR2 antagonists blocked the effects of low (< or =30 nM) but not high concentrations of VP, indicating that VP was affecting both AVPR2 and a second receptor subtype, likely OXTR or AVPR1A. Experiments employing chelerythrine demonstrated that OT stimulation of vas deferens monolayers requires PKC activity. Alternatively, VP (but not OT) increased the accumulation of cytosolic cAMP in vas deferens epithelial cells. Results from this study demonstrate that OT and VP can modulate ion transport across vas deferens epithelia by independent mechanisms. OT and VP have the potential to acutely change the environment to which sperm are exposed and thus, have the potential to affect male fertility.
Collapse
Affiliation(s)
- Travis M Hagedorn
- Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas 66506, USA
| | | | | |
Collapse
|
9
|
Milutinović S, Murphy D, Japundzić-Zigon N. The role of central vasopressin receptors in the modulation of autonomic cardiovascular controls: a spectral analysis study. Am J Physiol Regul Integr Comp Physiol 2006; 291:R1579-91. [PMID: 17085750 DOI: 10.1152/ajpregu.00764.2005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although it has been suggested that vasopressin (VP) acts within the central nervous system to modulate autonomic cardiovascular controls, the mechanisms involved are not understood. Using nonpeptide, selective V(1a), V(1b), and V(2) antagonists, in conscious rats, we assessed the roles of central VP receptors, under basal conditions, after the central application of exogenous VP, and after immobilization, on cardiovascular short-term variability. Equidistant sampling of blood pressure (BP) and heart rate (HR) at 20 Hz allowed direct spectral analysis in very-low frequency (VLF-BP), low-frequency (LF-BP), and high-frequency (HF-BP) blood pressure domains. The effect of VP antagonists and of exogenous VP on body temperature (T(b)) was also investigated. Under basal conditions, V(1a) antagonist increased HF-BP and T(b), and this was prevented by metamizol. V(1b) antagonist enhanced HF-BP without affecting T(b), and V(2) antagonist increased VLF-BP variability which could be prevented by quinapril. Immobilization increased BP, LF-BP, HF-BP, and HF-HR variability. V(1a) antagonist prevented BP and HR variability changes induced by immobilization and potentiated tachycardia. V(1b) antagonist prevented BP but not HR variability changes, whereas V(2) antagonist had no effect. Exogenous VP increased systolic arterial pressure (SAP) and HF-SAP variability, and this was prevented by V(1a) and V(1b) but not V(2) antagonist pretreatment. Our results suggest that, under basal conditions, VP, by stimulation of V(1a), V(1b), and cognate V(2) receptors, buffers BP variability, mostly due to thermoregulation. Immobilization and exogenous VP, by stimulation of V(1a) or V(1b), but not V(2) receptors, increases BP variability, revealing cardiorespiratory adjustment to stress and respiratory stimulation, respectively.
Collapse
Affiliation(s)
- Sanja Milutinović
- Laboratory for Cardiovascular Pharmacology, Institute of Pharmacology, Clinical Pharmacology and Toxicology, 11129 Belgrade, Serbia
| | | | | |
Collapse
|