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Moura Santos D, Ribeiro Marins F, Limborço-Filho M, de Oliveira ML, Hamamoto D, Xavier CH, Moreira FA, Santos RAS, Campagnole-Santos MJ, Peliky Fontes MA. Chronic overexpression of angiotensin-(1-7) in rats reduces cardiac reactivity to acute stress and dampens anxious behavior. Stress 2017; 20:189-196. [PMID: 28288545 DOI: 10.1080/10253890.2017.1296949] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Angiotensin II (Ang II) acts as a pro-stress hormone, while other evidence indicates that angiotensin-(1-7) [Ang-(1-7)] attenuates physiological responses to emotional stress. To further test this hypothesis, in groups of 5-6 rats we evaluated autonomic, cardiovascular and behavioral parameters in male Sprague-Dawley (SD) and transgenic TGR(A1-7)3292 (TG) rats chronically overexpressing Ang-(1-7). Compared to SD rats, TG rats showed reduced baseline heart rate (HR; SD 380 ± 16 versus TG 329 ± 9 beats per minute (bpm), mean ± standard error of mean, p < .05) and renal sympathetic discharge (SD 138 ± 4 versus TG 117 ± 5 spikes/second, p < .05). TG rats had an attenuated tachycardic response to acute air-puff stress (ΔHR: SD 51 ± 20 versus TG 1 ± 3 bpm; p < .05), which was reversed by intracerebroventricular injection of the Mas receptor antagonist, A-779 (ΔHR: SD 51 ± 20 versus TG 63 ± 15 bpm). TG rats showed less anxious behavior on the elevated plus maze, as revealed by more entries into open arms (SD 2 ± 2 versus TG 47 ± 5% relative to total entries; p < .05), and more time spent in the open arms (SD 5 ± 4 versus TG 53 ± 9% relative to total time, p < .05). By contrast with SD rats, diazepam (1.5 mg/kg, intraperitoneally) did not further reduce anxious behavior in TG rats, indicating a ceiling anxiolytic effect of Ang-(1-7) overexpression. Ang-(1-7) concentrations in hypothalamus and plasma, measured by mass spectrometry were two- and three-fold greater, respectively, in TG rats than in SD rats. Hence, increased endogenous Ang-(1-7) levels in TG rats diminishes renal sympathetic outflow and attenuates cardiac reactivity to emotional stress, which may be via central Mas receptors, and reduces anxious behavior. Lay summaryWe used a genetically modified rat model that produces above normal amounts of a peptide hormone called angiotensin-(1-7) to test whether this peptide can reduce some of the effects of stress. We found that angiotensin-(1-7), acting in the brain, can reduce anxiety and reduce the increase in heart rate associated with emotional stress. These findings may provide a lead for design of new drugs to reduce stress.
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Affiliation(s)
- Danielle Moura Santos
- a Department of Physiology and Biophysics , INCT, Institute of Biological Sciences, Federal University of Minas Gerais , Minas Gerais , Brazil
| | - Fernanda Ribeiro Marins
- a Department of Physiology and Biophysics , INCT, Institute of Biological Sciences, Federal University of Minas Gerais , Minas Gerais , Brazil
| | - Marcelo Limborço-Filho
- a Department of Physiology and Biophysics , INCT, Institute of Biological Sciences, Federal University of Minas Gerais , Minas Gerais , Brazil
| | - Marilene Luzia de Oliveira
- a Department of Physiology and Biophysics , INCT, Institute of Biological Sciences, Federal University of Minas Gerais , Minas Gerais , Brazil
| | | | - Carlos Henrique Xavier
- c Department of Physiology , Institute of Biological Sciences, Federal University of Goiás , Goiás , Brazil Goiânia
| | - Fabrício Araújo Moreira
- d Department of Pharmacology , Institute of Biological Sciences, Federal University of Minas Gerais , Minas Gerais , Brazil
| | - Robson Augusto Souza Santos
- a Department of Physiology and Biophysics , INCT, Institute of Biological Sciences, Federal University of Minas Gerais , Minas Gerais , Brazil
- b Alamantec/LABFAR , Minas Gerais , Brazil
- e Institute of Cardiology , University Foundation of Cardiology , Rio Grande do Sul , Brazil
| | - Maria José Campagnole-Santos
- a Department of Physiology and Biophysics , INCT, Institute of Biological Sciences, Federal University of Minas Gerais , Minas Gerais , Brazil
| | - Marco Antonio Peliky Fontes
- a Department of Physiology and Biophysics , INCT, Institute of Biological Sciences, Federal University of Minas Gerais , Minas Gerais , Brazil
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Martins Lima A, Xavier CH, Ferreira AJ, Raizada MK, Wallukat G, Velloso EPP, dos Santos RAS, Fontes MAP. Activation of angiotensin-converting enzyme 2/angiotensin-(1-7)/Mas axis attenuates the cardiac reactivity to acute emotional stress. Am J Physiol Heart Circ Physiol 2013; 305:H1057-67. [PMID: 23873801 DOI: 10.1152/ajpheart.00433.2013] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Recent data indicate the brain angiotensin-converting enzyme/ANG II/AT1 receptor axis enhances emotional stress responses. In this study, we investigated whether its counterregulatory axis, the angiotensin-converting enzyme 2 (ACE2)/ANG-(1-7)/Mas axis, attenuate the cardiovascular responses to acute emotional stress. In conscious male Wistar rats, the tachycardia induced by acute stress (air jet 10 l/min) was attenuated by intravenous injection of ANG-(1-7) [Δ heart rate (HR): saline 136 ± 22 vs. ANG-(1-7) 61 ± 25 beats/min; P < 0.05]. Peripheral injection of the ACE2 activator compound, XNT, abolished the tachycardia induced by acute stress. We found a similar effect after intracerebroventricular injections of either ANG-(1-7) or XNT. Under urethane anesthesia, the tachycardia evoked by the beta-adrenergic agonist was markedly reduced by ANG-(1-7) [ΔHR: saline 100 ± 16 vs. ANG-(1-7) 18 ± 15 beats/min; P < 0.05]. The increase in renal sympathetic nerve activity (RSNA) evoked by isoproterenol was also abolished after the treatment with ANG-(1-7) [ΔRSNA: saline 39% vs. ANG-(1-7) -23%; P < 0.05]. The tachycardia evoked by disinhibition of dorsomedial hypothalamus neurons, a key nucleus for the cardiovascular response to emotional stress, was reduced by ∼45% after intravenous injection of ANG-(1-7). In cardiomyocyte, the incubation with ANG-(1-7) (1 μM) markedly attenuated the increases in beating rate induced by isoproterenol. Our data show that activation of the ACE2/ANG-(1-7)/Mas axis attenuates stress-induced tachycardia. This effect might be either via the central nervous system reducing anxiety level and/or interfering with the positive chronotropy mediated by activation of cardiac β adrenergic receptors. Therefore, ANG-(1-7) might contribute to reduce the sympathetic load to the heart during situations of emotional stress, reducing the cardiovascular risk.
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Affiliation(s)
- Augusto Martins Lima
- National Institute of Science and Technology in Nanobiopharmaceutics (INCT-Nanobiofar Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
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