1
|
Filice M, Barca A, Amelio D, Leo S, Mazzei A, Del Vecchio G, Verri T, Cerra MC, Imbrogno S. Morpho-functional remodelling of the adult zebrafish (Danio rerio) heart in response to waterborne angiotensin II exposure. Gen Comp Endocrinol 2021; 301:113663. [PMID: 33220301 DOI: 10.1016/j.ygcen.2020.113663] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 11/04/2020] [Accepted: 11/12/2020] [Indexed: 12/29/2022]
Abstract
Angiotensin II (AngII), the principal effector of the Renin-Angiotensin System, is a pluripotent humoral agent whose biological actions include short-term modulations and long-term adaptations. In fish, short-term cardio-tropic effects of AngII are documented, but information on the role of AngII in long-term cardiac remodelling is not fully understood. Here, we describe a direct approach to disclose long-term morpho-functional effects of AngII on the zebrafish heart. Adult fish exposed to waterborne teleost analogue AngII for 8 weeks showed enhanced heart weight and cardio-somatic index, coupled to myocardial structural changes (i.e. augmented compacta thickness and fibrosis), and increased heart rate. These findings were paralleled by an up-regulation of type-1 and type-2 AngII receptors expression, and by changes in the expression of GATA binding protein 4, nuclear factor of kappa light polypeptide gene enhancer in B-cells 1 and superoxide dismutase 1 soluble mRNAs, as well as of cytochrome b-245 beta polypeptide protein, indicative of cardiac remodelling. Our results suggest that waterborne AngII can sustain and robustly affect the cardiac morpho-functional remodelling of adult zebrafish.
Collapse
Affiliation(s)
- Mariacristina Filice
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Arcavacata di Rende, CS, Italy
| | - Amilcare Barca
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Provinciale Lecce-Monteroni, I-73100 Lecce, Italy
| | - Daniela Amelio
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Arcavacata di Rende, CS, Italy
| | - Serena Leo
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Arcavacata di Rende, CS, Italy
| | - Aurora Mazzei
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Provinciale Lecce-Monteroni, I-73100 Lecce, Italy
| | - Gianmarco Del Vecchio
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Provinciale Lecce-Monteroni, I-73100 Lecce, Italy
| | - Tiziano Verri
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Provinciale Lecce-Monteroni, I-73100 Lecce, Italy
| | - Maria Carmela Cerra
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Arcavacata di Rende, CS, Italy
| | - Sandra Imbrogno
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Arcavacata di Rende, CS, Italy.
| |
Collapse
|
2
|
MacDonald EA, Rose RA, Quinn TA. Neurohumoral Control of Sinoatrial Node Activity and Heart Rate: Insight From Experimental Models and Findings From Humans. Front Physiol 2020; 11:170. [PMID: 32194439 PMCID: PMC7063087 DOI: 10.3389/fphys.2020.00170] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 02/13/2020] [Indexed: 12/22/2022] Open
Abstract
The sinoatrial node is perhaps one of the most important tissues in the entire body: it is the natural pacemaker of the heart, making it responsible for initiating each-and-every normal heartbeat. As such, its activity is heavily controlled, allowing heart rate to rapidly adapt to changes in physiological demand. Control of sinoatrial node activity, however, is complex, occurring through the autonomic nervous system and various circulating and locally released factors. In this review we discuss the coupled-clock pacemaker system and how its manipulation by neurohumoral signaling alters heart rate, considering the multitude of canonical and non-canonical agents that are known to modulate sinoatrial node activity. For each, we discuss the principal receptors involved and known intracellular signaling and protein targets, highlighting gaps in our knowledge and understanding from experimental models and human studies that represent areas for future research.
Collapse
Affiliation(s)
- Eilidh A. MacDonald
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada
| | - Robert A. Rose
- Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - T. Alexander Quinn
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
| |
Collapse
|
3
|
Margiotta-Casaluci L, Owen SF, Rand-Weaver M, Winter MJ. Testing the Translational Power of the Zebrafish: An Interspecies Analysis of Responses to Cardiovascular Drugs. Front Pharmacol 2019; 10:893. [PMID: 31474857 PMCID: PMC6707810 DOI: 10.3389/fphar.2019.00893] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 07/16/2019] [Indexed: 12/04/2022] Open
Abstract
The zebrafish is rapidly emerging as a promising alternative in vivo model for the detection of drug-induced cardiovascular effects. Despite its increasing popularity, the ability of this model to inform the drug development process is often limited by the uncertainties around the quantitative relevance of zebrafish responses compared with nonclinical mammalian species and ultimately humans. In this test of concept study, we provide a comparative quantitative analysis of the in vivo cardiovascular responses of zebrafish, rat, dog, and human to three model compounds (propranolol, losartan, and captopril), which act as modulators of two key systems (beta-adrenergic and renin–angiotensin systems) involved in the regulation of cardiovascular functions. We used in vivo imaging techniques to generate novel experimental data of drug-mediated cardiovascular effects in zebrafish larvae. These data were combined with a database of interspecies mammalian responses (i.e., heart rate, blood flow, vessel diameter, and stroke volume) extracted from the literature to perform a meta-analysis of effect size and direction across multiple species. In spite of the high heterogeneity of study design parameters, our analysis highlighted that zebrafish and human responses were largely comparable in >80% of drug/endpoint combinations. However, it also revealed a high intraspecies variability, which, in some cases, prevented a conclusive interpretation of the drug-induced effect. Despite the shortcomings of our study, the meta-analysis approach, combined with a suitable data visualization strategy, enabled us to observe patterns of response that would likely remain undetected with more traditional methods of qualitative comparative analysis. We propose that expanding this approach to larger datasets encompassing multiple drugs and modes of action would enable a rigorous and systematic assessment of the applicability domain of the zebrafish from both a mechanistic and phenotypic standpoint. This will increase the confidence in its application for the early detection of adverse drug reactions in any major organ system.
Collapse
Affiliation(s)
| | - Stewart F Owen
- Global Safety, Health & Environment, AstraZeneca, Alderley Park, Macclesfield, United Kingdom
| | - Mariann Rand-Weaver
- College of Health and Life Sciences, Brunel University London, London, United Kingdom
| | - Matthew J Winter
- School of Biosciences, College of Life and Environmental Science, University of Exeter, Exeter, United Kingdom
| |
Collapse
|
4
|
|
5
|
Raifman TK, Kumar P, Haase H, Klussmann E, Dascal N, Weiss S. Protein kinase C enhances plasma membrane expression of cardiac L-type calcium channel, Ca V1.2. Channels (Austin) 2017; 11:604-615. [PMID: 28901828 DOI: 10.1080/19336950.2017.1369636] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
L-type-voltage-dependent Ca2+ channels (L-VDCCs; CaV1.2, α1C), crucial in cardiovascular physiology and pathology, are modulated via activation of G-protein-coupled receptors and subsequently protein kinase C (PKC). Despite extensive study, key aspects of the mechanisms leading to PKC-induced Ca2+ current increase are unresolved. A notable residue, Ser1928, located in the distal C-terminus (dCT) of α1C was shown to be phosphorylated by PKC. CaV1.2 undergoes posttranslational modifications yielding full-length and proteolytically cleaved CT-truncated forms. We have previously shown that, in Xenopus oocytes, activation of PKC enhances α1C macroscopic currents. This increase depended on the isoform of α1C expressed. Only isoforms containing the cardiac, long N-terminus (L-NT), were upregulated by PKC. Ser1928 was also crucial for the full effect of PKC. Here we report that, in Xenopus oocytes, following PKC activation the amount of α1C protein expressed in the plasma membrane (PM) increases within minutes. The increase in PM content is greater with full-length α1C than in dCT-truncated α1C, and requires Ser1928. The same was observed in HL-1 cells, a mouse atrium cell line natively expressing cardiac α1C, which undergoes the proteolytic cleavage of the dCT, thus providing a native setting for exploring the effects of PKC in cardiomyocytes. Interestingly, activation of PKC preferentially increased the PM levels of full-length, L-NT α1C. Our findings suggest that part of PKC regulation of CaV1.2 in the heart involves changes in channel's cellular fate. The mechanism of this PKC regulation appears to involve the C-terminus of α1C, possibly corroborating the previously proposed role of NT-CT interactions within α1C.
Collapse
Affiliation(s)
- Tal Keren Raifman
- a Department of Physiology and Pharmacology , Sackler School of Medicine, Tel Aviv University , Tel Aviv , Israel.,b Department of Physiotherapy , Zfat Academic College , Zfat , Israel
| | - Prabodh Kumar
- a Department of Physiology and Pharmacology , Sackler School of Medicine, Tel Aviv University , Tel Aviv , Israel
| | - Hannelore Haase
- c Max Delbruck Center for Molecular Medicine (MDC) , Berlin , Germany
| | - Enno Klussmann
- c Max Delbruck Center for Molecular Medicine (MDC) , Berlin , Germany
| | - Nathan Dascal
- a Department of Physiology and Pharmacology , Sackler School of Medicine, Tel Aviv University , Tel Aviv , Israel
| | - Sharon Weiss
- a Department of Physiology and Pharmacology , Sackler School of Medicine, Tel Aviv University , Tel Aviv , Israel
| |
Collapse
|
6
|
MacDonald EA, Stoyek MR, Rose RA, Quinn TA. Intrinsic regulation of sinoatrial node function and the zebrafish as a model of stretch effects on pacemaking. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:198-211. [PMID: 28743586 DOI: 10.1016/j.pbiomolbio.2017.07.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 07/17/2017] [Accepted: 07/21/2017] [Indexed: 12/18/2022]
Abstract
Excitation of the heart occurs in a specialised region known as the sinoatrial node (SAN). Tight regulation of SAN function is essential for the maintenance of normal heart rhythm and the response to (patho-)physiological changes. The SAN is regulated by extrinsic (central nervous system) and intrinsic (neurons, peptides, mechanics) factors. The positive chronotropic response to stretch in particular is essential for beat-by-beat adaptation to changes in hemodynamic load. Yet, the mechanism of this stretch response is unknown, due in part to the lack of an appropriate experimental model for targeted investigations. We have been investigating the zebrafish as a model for the study of intrinsic regulation of SAN function. In this paper, we first briefly review current knowledge of the principal components of extrinsic and intrinsic SAN regulation, derived primarily from experiments in mammals, followed by a description of the zebrafish as a novel experimental model for studies of intrinsic SAN regulation. This mini-review is followed by an original investigation of the response of the zebrafish isolated SAN to controlled stretch. Stretch causes an immediate and continuous increase in beating rate in the zebrafish isolated SAN. This increase reaches a maximum part way through a period of sustained stretch, with the total change dependent on the magnitude and direction of stretch. This is comparable to what occurs in isolated SAN from most mammals (including human), suggesting that the zebrafish is a novel experimental model for the study of mechanisms involved in the intrinsic regulation of SAN function by mechanical effects.
Collapse
Affiliation(s)
- Eilidh A MacDonald
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Canada
| | - Matthew R Stoyek
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Canada
| | - Robert A Rose
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - T Alexander Quinn
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Canada; School of Biomedical Engineering, Dalhousie University, Halifax, Canada.
| |
Collapse
|
7
|
Becari C, Silva MAB, Durand MT, Prado CM, Oliveira EB, Ribeiro MS, Salgado HC, Salgado MCO, Tostes RC. Elastase-2, an angiotensin II-generating enzyme, contributes to increased angiotensin II in resistance arteries of mice with myocardial infarction. Br J Pharmacol 2017; 174:1104-1115. [PMID: 28222221 DOI: 10.1111/bph.13755] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 02/08/2017] [Accepted: 02/11/2017] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE Angiotensin II (Ang II), whose generation largely depends on angiotensin-converting enzyme (ACE) activity, mediates most of the renin-angiotensin-system (RAS) effects. Elastase-2 (ELA-2), a chymotrypsin-serine protease elastase family member 2A, alternatively generates Ang II in rat arteries. Myocardial infarction (MI) leads to intense RAS activation, but mechanisms involved in Ang II-generation in resistance arteries are unknown. We hypothesized that ELA-2 contributes to vascular Ang II generation and cardiac damage in mice subjected to MI. EXPERIMENTAL APPROACH Concentration-effect curves to Ang I and Ang II were performed in mesenteric resistance arteries from male wild type (WT) and ELA-2 knockout (ELA-2KO) mice subjected to left anterior descending coronary artery ligation (MI). KEY RESULTS MI size was similar in WT and ELA-2KO mice. Ejection fraction and fractional shortening after MI similarly decreased in both strains. However, MI decreased stroke volume and cardiac output in WT, but not in ELA-2KO mice. Ang I-induced contractions increased in WT mice subjected to MI (MI-WT) compared with sham-WT mice. No differences were observed in Ang I reactivity between arteries from ELA-2KO and ELA-2KO subjected to MI (MI-ELA-2KO). Ang I contractions increased in arteries from MI-WT versus MI-ELA-2KO mice. Chymostatin attenuated Ang I-induced vascular contractions in WT mice, but did not affect Ang I responses in ELA-2KO arteries. CONCLUSIONS AND IMPLICATIONS These results provide the first evidence that ELA-2 contributes to increased Ang II formation in resistance arteries and modulates cardiac function after MI, implicating ELA-2 as a key player in ACE-independent dysregulation of the RAS.
Collapse
Affiliation(s)
- Christiane Becari
- Departments of Pharmacology, University of Sao Paulo, Ribeirao Preto, SP, Brazil.,Physiology, University of Sao Paulo, Ribeirao Preto, SP, Brazil.,Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA
| | - Marcondes A B Silva
- Departments of Pharmacology, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Marina T Durand
- Physiology, University of Sao Paulo, Ribeirao Preto, SP, Brazil.,Department of Medicine, University of Ribeirão Preto, Ribeirão Preto, SP, Brazil
| | - Cibele M Prado
- Pathology and Legal Medicine, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Eduardo B Oliveira
- Biochemistry and Immunology, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Mauricio S Ribeiro
- Surgery and Anatomy, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Helio C Salgado
- Physiology, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | | | - Rita C Tostes
- Departments of Pharmacology, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| |
Collapse
|
8
|
Rademaker MT, Yandle TG, Ellmers LJ, Charles CJ, Nicholls MG, Richards AM. Hemodynamic, Hormonal, and Renal Effects of (Pro)Renin Receptor Blockade in Experimental Heart Failure. Circ Heart Fail 2012; 5:645-52. [DOI: 10.1161/circheartfailure.112.967059] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Background—
The (pro)renin receptor (P)RR is implicated in blood pressure regulation and the pathophysiology of heart failure (HF). The effects of (P)RR blockade in HF have not been previously investigated.
Methods and Results—
Eight sheep received on 2 separate days a vehicle control and incremental intravenous boluses of a (P)RR antagonist, ovine handle region peptide (HRP) (1, 5, and 25 mg at 90-minute intervals), both before (normal) and after induction of HF by rapid left ventricular pacing. In normal sheep, HRP reduced heart rate (
P
<0.001) and hematocrit (
P
=0.019) compared with time-matched control data, without significantly affecting any other hemodynamic, hormonal, or renal variables. In sheep with HF, HRP treatment induced progressive falls in mean arterial pressure (
P
<0.001) in association with decreases in left atrial pressure (
P
<0.001), peripheral resistance (
P
=0.014), and hematocrit (
P
<0.001). Cardiac contractility tended to decline (
P
=0.096), whereas cardiac output was unaltered. HRP administration produced a dose-dependent decrease in plasma renin activity (
P
=0.004), with similar trends observed for plasma angiotensin II and aldosterone (
P
=0.093 and
P
=0.088, respectively). Circulating natriuretic peptides, endothelin-1, and catecholamine levels were unchanged. HRP also induced a reduction in plasma sodium concentrations relative to control (
P
=0.024), a natriuresis (
P
=0.046), and a tendency for creatinine excretion and clearance to improve.
Conclusions—
(P)RR antagonism in experimental HF resulted in cardiovascular and renal benefits in association with inhibition of the renin-angiotensin-aldosterone system. These findings suggest that (P)RR contributes to pressure/volume regulation in HF and identifies the receptor as a potential therapeutic target in this disease.
Collapse
Affiliation(s)
- Miriam T. Rademaker
- From the Christchurch Heart Institute, University of Otago, Christchurch, New Zealand
| | - Tim G. Yandle
- From the Christchurch Heart Institute, University of Otago, Christchurch, New Zealand
| | - Leigh J. Ellmers
- From the Christchurch Heart Institute, University of Otago, Christchurch, New Zealand
| | | | - M. Gary Nicholls
- From the Christchurch Heart Institute, University of Otago, Christchurch, New Zealand
| | - A. Mark Richards
- From the Christchurch Heart Institute, University of Otago, Christchurch, New Zealand
| |
Collapse
|
9
|
Angiotensin II decreases spontaneous firing rate of guinea-pig sino-atrial node cells. Eur J Pharmacol 2011; 660:387-93. [PMID: 21510929 DOI: 10.1016/j.ejphar.2011.04.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Revised: 03/24/2011] [Accepted: 04/06/2011] [Indexed: 11/22/2022]
Abstract
Angiotensin II (Ang II) plays an important role in the regulation of cardiac function, but its electrophysiological effects on sino-atrial (SA) node are not well understood. In this study, the immediate effect of Ang II on action potentials and ionic currents were investigated by using whole-cell patch-clamps in single guinea-pig SA node pacemaker cells. We demonstrated that Ang II exerted a negative effect on spontaneous firing rate, with a concomitant reduction in the slope of diastolic depolarization. The inhibitory effect of Ang II on spontaneous activity displayed a concentration-dependent manner in the range of 1-1000 nM, with IC50 of 8.34 nM. Ang II type 1 (AT1) receptor antagonist valsartan (1 μM) abolished the inhibitory effect. In contrast, Ang II type 2 (AT2) receptor antagonist, PD123319 (1 μM) didn't affect the action of Ang II. Ang II had no significant effect on hyperpolarization-activated current (If) in SA node cells. However, it significantly slowed the deactivation of the slowly activated delayed rectifier K+ current (Iks) and increased the tail current density. Furthermore, Ang II decreased the current density of L-type Ca2+ current in SA node cells. Our data demonstrate that Ang II reduces the auto rhythm of SA node cells via enhancing Iks and reducing ICaL. The result suggests a potential mechanism by which elevated levels of Ang II may be involved in the occurrence of SA node dysfunction in cardiac pathophysiology.
Collapse
|
10
|
Weiss S, Doan T, Bernstein KE, Dascal N. Modulation of Cardiac Ca2+ Channel by Gq-activating Neurotransmitters Reconstituted in Xenopus Oocytes. J Biol Chem 2004; 279:12503-10. [PMID: 14722109 DOI: 10.1074/jbc.m310196200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
L-type dihydropyridine-sensitive voltage dependent Ca(2+) channels (L-VDCCs; alpha(1C)) are crucial in cardiovascular physiology. Currents via L-VDCCs are enhanced by hormones and transmitters operating via G(q), such as angiotensin II (AngII) and acetylcholine (ACh). It has been proposed that these modulations are mediated by protein kinase C (PKC). However, reports on effects of PKC activators on L-type channels are contradictory; inhibitory and/or enhancing effects have been observed. Attempts to reproduce the enhancing effect of AngII in heterologous expression systems failed. We previously found that PKC modulation of the channel depends on alpha(1C) isoform used; only a long N-terminal (NT) isoform was up-regulated. Here we report the reconstitution of the AngII- and ACh-induced enhancement of the long-NT isoform of L-VDCC expressed in Xenopus oocytes. The current initially increased over several minutes but later declined to below baseline levels. Using different NT deletion mutants and human short- and long-NT isoforms of the channel, we found the initial segment of the NT to be crucial for the enhancing, but not for the inhibitory, effect. Using blockers of PKC and of phospholipase C (PLC) and a mutated AngII receptor lacking G(q) coupling, we demonstrate that the signaling pathway of the enhancing effect includes the activation of G(q), PLC, and PKC. The inhibitory modulation, present in both alpha(1C) isoforms, was G(q)- and PLC-independent and Ca(2+)-dependent, but not Ca(2+)-mediated, as only basal levels of Ca(2+) were essential. Reconstitution of AngII and ACh effects in Xenopus oocytes will advance the study of molecular mechanisms of these physiologically important modulations.
Collapse
Affiliation(s)
- Sharon Weiss
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Ramat Aviv 69978, Israel
| | | | | | | |
Collapse
|
11
|
Molinari C, Battaglia A, Grossini E, Mary DA, Ruggeri P, Surico N, Vacca G, Vassanelli C. The role of activation of the renin-angiotensin system on the reflex regional vasoconstriction caused by distension of the uterus in anaesthetized pigs. Auton Neurosci 2001; 93:56-64. [PMID: 11695707 DOI: 10.1016/s1566-0702(01)00333-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Distension of the uterus in anaesthetized pigs has been shown to cause a reflex regional vasoconstriction and an increase in plasma renin activity (PRA) through efferent sympathetic mechanisms which respectively involved alpha- and beta-adrenergic receptors. The present study was undertaken to determine the possible contribution of the activation of the renin-angiotensin system (RAS) to the observed regional vasoconstrictive responses to uterus distension. In pigs anaesthetized with alpha-chloralose, blood flow in the left circumflex or anterior descending coronary, superior mesenteric, left renal and left external iliac arteries was assessed using electromagnetic flowmeters. Distension of the uterus for periods of 30 min was performed by injecting 20 ml of warm Ringer solution into balloons positioned within the viscus before and after blockade of angiotensin II receptors with losartan. Changes in heart rate and renal blood flows were respectively prevented by atrial pacing and injection of phentolamine into the renal arteries. Changes in baroreceptors activity and in regional perfusion pressure were minimized by section of cervical vagus nerves and denervation of carotid sinuses and by an aortic constriction. PRA was assessed during the last minute of distension by radioimmunoassay of angiotensin 1. Before blockade of angiotensin II receptors, in six pigs, distension of the uterus decreased coronary blood flow by 19%, and in other six pigs, decreased mesenteric and iliac blood flows by 13.1% and 29.4% in the absence of changes in arterial perfusion pressure. After losartan, these decreases were significantly reduced to 11.7%, 8.2% and 18%. These results showed that the activation of the RAS significantly contributed to the alpha-adrenergic receptor-mediated regional vasoconstrictive responses reflexly elicited by distension of the uterus.
Collapse
Affiliation(s)
- C Molinari
- Dipartimento di Scienze Mediche, Facoltà di Medicina e Chirurgia, Università del Piemonte Orientale A. Avogadro, Novara, Italy.
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Molinari C, Grossini E, Mary DA, Vacca G. Effect of distension of the gallbladder on plasma renin activity in anesthetized pigs. Circulation 2000; 101:2539-45. [PMID: 10831530 DOI: 10.1161/01.cir.101.21.2539] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Gallbladder pathology has been associated with cardiovascular disease. Recently, we showed that gallbladder distension in anesthetized pigs reflexly increased heart rate, arterial pressure, and coronary and renal vascular resistance through efferent sympathetic mechanisms. Renin release is affected by sympathetic output, and angiotensin liberation may result in vasoconstriction. This study was undertaken to determine whether gallbladder distension primarily causes a reflex change in plasma renin activity (PRA) and to assess its influence on observed pressor and coronary responses as well as on regional vascular resistance. METHODS AND RESULTS In 34 alpha-chloralose-anesthetized pigs, balloons positioned within the gallbladder were distended for 30 minutes with volumes of Ringer's solution equal to those of withdrawn bile. In 19 pigs, gallbladder distension at constant heart rate, arterial pressure, and renal flow increased PRA in the absence of changes in urinary sodium excretion. This increase was abolished by cervical vagotomy, section of renal nerves, or blockade of beta-adrenergic receptors. In another 15 pigs, blockade of angiotensin II receptors significantly attenuated the pressor and coronary, mesenteric, and iliac vasoconstriction responses to gallbladder distension. CONCLUSIONS The present study showed that innocuous gallbladder distension primarily caused a reflex increase in PRA. This increase, which involved afferent vagal pathways and efferent sympathetic mechanisms related to beta-adrenergic receptors, contributed significantly to the pressor and coronary, mesenteric, and iliac vasoconstriction responses to gallbladder distension.
Collapse
Affiliation(s)
- C Molinari
- Dipartimento di Scienze Mediche, Facoltà di Medicina e Chirurgia di Novara, Università del Piemonte Orientale A. Avogadro, and the Servizio di Chirugia Sperimentale, Azienda Sanitaria Ospedaliera "Maggiore della, Novara, Italy
| | | | | | | |
Collapse
|
13
|
Beaulieu P, Cardinal R, De Léan A, Lambert C. Direct chronotropic effects of atrial and C-type natriuretic peptides in anaesthetized dogs. Br J Pharmacol 1996; 118:1790-6. [PMID: 8842445 PMCID: PMC1909842 DOI: 10.1111/j.1476-5381.1996.tb15605.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
1. The chronotropic effects of atrial natriuretic peptide (ANP) and C-type natriuretic peptide (CNP) were investigated using injections (50 micrograms in 1 ml of Tyrode solution as bolus over 1 min) directly into the sinus node artery of 21 anaesthetized and vagotomized dogs which had been pretreated with a beta-adrenoceptor antagonist. The injections were also repeated following: (a) alpha-adrenoceptor antagonism (prazosin) and muscarinic receptor antagonism (atropine); (b) inhibition of prostaglandin synthesis (indomethacin); (c) angiotensin II AT1 receptor antagonism (losartan); (d) histamine H1 (mepyramine) and H2 (cimetidine) receptor antagonism. 2. The results obtained indicate that ANP had no significant effect on the basal sinus rate, whereas CNP produced a slight but significant increase of 12 +/- 2 beats min-1. The effect of CNP was long-lasting (return to pre-injection levels after maximum effect in 17 +/- 3 min) and was not influenced by the various antagonists mentioned above. 3. During in vitro experiments on spontaneously beating right atria isolated from 6 dogs, the injection of CNP (50 micrograms in 1 ml of Tyrode solution) into the sinus node artery produced an increase in atrial rate of 14 +/- 1 beats min-1. 4. The results of this work indicate that CNP exerts a significant and prolonged positive chronotropic effect both in vivo and in vitro. Other studies are required to elucidate the mechanism of action of CNP on the heart conduction system, to ascertain the presence of natriuretic peptide receptor B in the region of the sinoatrial node and to determine the role of CNP in the control of heart rate.
Collapse
Affiliation(s)
- P Beaulieu
- Department of Pharmacology, Faculty of Medicine, Université de Montréal, Québec, Canada
| | | | | | | |
Collapse
|
14
|
Li Q, Zhang J, Pfaffendorf M, van Zwieten PA. Direct positive chronotropic effects of angiotensin II and angiotensin III in pithed rats and in rat isolated atria. Br J Pharmacol 1996; 118:1653-8. [PMID: 8842428 PMCID: PMC1909819 DOI: 10.1111/j.1476-5381.1996.tb15588.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
1. The direct positive chronotropic effects of angiotensin II (AII) and its degradation products angiotensin III (AIII) and angiotensin IV (AIV) were established in pithed rats and in rat spontaneously beating right atria. 2. In pithed rats, AII, AIII and AIV caused dose-dependent tachycardia with similar maximal responses (110 beats min-1). The beta-adrenoceptor antagonist propranolol (3.37 x 10(-6) mol kg-1) but not the alpha 1-adrenoceptor antagonist prazosin (2.38 x 10(-7) mol kg-1) significantly reduced these effects (P < 0.05; n = 7-8), but 20-25% of the responses could not be blocked by propranolol. 3. In isolated atria, AII, AIII and AIV caused concentration-dependent increases in beating rate with similar maximal responses to AII and AIII (34.3 +/- 0.4 and 34.7 +/- 0.4 beats min-1; n = 9-10), and a lower maximal response to AIV (26.8 +/- 0.6 beats min-1; P < 0.05; n = 8). AIII was about 9 times less potent than AII, whereas AIV proved approximately 3800 times less potent than AII. Neither propranolol (1 microM) nor prazosin (1 microM) could influence the effects of the angiotensin peptides. 4. In isolated atria, the selective AT1-receptor antagonist, losartan (10, 100 and 300 nM) caused parallel rightward shifts of the concentration-response curves for AII and AIII, whereas the selective AT2- receptor antagonist PD123177 (1 microM) did not influence the effects of AII and AIII. The aminopeptidase-A and -M inhibitor amastatin (10 microM), significantly steepened the slope of the AIII curves and increased the potency of AIII about 6 fold. Amastatin did not influence the responses to AII. 5. Our results indicate that both in vivo and in vitro, exogenous AII and AIII induced a direct dose-dependent chronotropic effect, which is independent of the adrenergic system. This chronotropic effect is mediated by AT1-subtype receptors.
Collapse
Affiliation(s)
- Q Li
- Department of Pharmacotherapy, University of Amsterdam, The Netherlands
| | | | | | | |
Collapse
|
15
|
Bastien NR, Ciuffo GM, Saavedra JM, Lambert C. Angiotensin II receptor expression in the conduction system and arterial duct of neonatal and adult rat hearts. REGULATORY PEPTIDES 1996; 63:9-16. [PMID: 8795083 DOI: 10.1016/0167-0115(96)00012-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Paralleling the classic circulating system, recent evidence has demonstrated the presence of a cardiac renin-angiotensin system, as well as the synthesis of angiotensin II in the heart. Two receptors for angiotensin II have been identified and classified as AT1 and AT2. The proportions of these receptor subtypes vary with the tissues, species and stage of development. From the results of other studies, it might be generalized that the expression of angiotensin II receptors and the proportion of AT2 receptor subtype are much higher in fetal and neonatal tissues than in the same tissues from an adult. The aim of this study was to specifically evaluate the AT1/AT2 ratio in the neonatal and adult conduction systems of rat hearts by means of quantitative autoradiogrphy. In the neonatal hearts, angiotensin II binding sites were highly concentrated in the vasculature, arterial duct, and conduction system, whereas their concentrations were barely detectable in the myocardium. Incubation with selective angiotensin II receptor ligands (losartan and CGP 42112) revealed that AT2 was the major subtype in vasculature (86 +/- 3%) and conduction system (73 +/- 4%). In the adult conduction system, the total expression of angiotensin II receptors was greatly reduced meanwhile the AT1 receptors represented the major proportion of the binding sites (80 +/- 3%). Our results demonstrated that the pattern of angiotensin II receptor expression in the conduction system of the rat heart is developmentally regulated. We suggest, as others have already, that the renin-angiotensin system plays a role during the early stage of cardiac development.
Collapse
Affiliation(s)
- N R Bastien
- Department of Pharmacology, Université de Montréal, Québec, Canada
| | | | | | | |
Collapse
|