Activation of angiotensin-converting enzyme 2/Angiotensin-(1-7)/Mas axis attenuates the cardiac reactivity to acute emotional stress

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Item Type:	Article
Title:	Activation of angiotensin-converting enzyme 2/Angiotensin-(1-7)/Mas axis attenuates the cardiac reactivity to acute emotional stress
Creators Name:	Martins Lima, A., Xavier, C.H., Ferreira, A.J., Raizada, M.K., Wallukat, G., Santos, R.A.S. and Fontes, M.A.P.
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) [Delta 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) [DeltaHR: 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) [DeltaRSNA: 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 approximately 45% after intravenous injection of ANG-(1-7). In cardiomyocyte, the incubation with ANG-(1-7) (1 muM) 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 beta 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.
Keywords:	Angiotensin, Cardiovascular, Stress, Animals, Rats
Source:	American Journal of Physiology Heart and Circulatory Physiology
ISSN:	0363-6135
Publisher:	American Physiological Society
Volume:	305
Number:	7
Page Range:	H1057-H1067
Date:	1 October 2013
Official Publication:	https://doi.org/10.1152/ajpheart.00433.2013
PubMed:	View item in PubMed

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