Cardiovascular and Behavioral Effects of Emotional Stress: The Participation of Renin- Angiotensin System
Pp. 250-274 (25)
Fernanda Klein Marcondes, Vander José das Neves, Rafaela Costa, Andrea Sanches, Tatiana Sousa Cunha, Maria José Costa Sampaio Moura and Dulce Elena Casarini
Abstract
Stress reaction aims to preserve body homeostasis. During stress, the reninangiotensin
system (RAS) increases the effects of the sympathetic nervous system and
the hypothalamic-pituitary- adrenal (HPA) axis so that the organism will adapt to
stressors. However, during chronic stress, these responses are sustained, adaptation
does not occur and pathologies might be developed. In this chapter, we address
evidences towards the correlation between RAS and the negative effects that stress has
on behavior and cardiovascular system. Both circulating and local RAS are involved in
stress – related hypertension. Among the mechanisms involved, it has been
demonstrated that RAS activates HPA axis, catecholamines upregulate the renin
synthesis and RAS activity in the peripheral organs, and vascular effects of angiotensin
II (Ang II) impair the balance between vascular relaxing and contracting agents.
Considering cardiac hypertrophy, hyperactivity of RAS and SNS promotes growth
factors increase, fibroblast proliferation and collagen synthesis in the myocardium. Ang II triggers the production of superoxide and acts as a pro-inflammatory molecule in the
blood vessels, and, consequently, might initiate and aggravate the process of
atherosclerosis. Considering emotional and cognitive effects of stress, there is a link
between depression and dysfunction of stress response systems involving the activation
of RAS. In treating hypertension, patients having depression might also benefit from
RAS blockers as these agents are known to have antidepressant effects. Inhibitors of
ACE have been reported to improve cognition and memory, via Ang II conversion to
Ang IV in the central nervous system. Stress-induced brain RAS has also been
suggested as having a role in Alzheimer’s disease.
Keywords:
Anxiety, Atherosclerosis, Cognition, Depression, Emotion, Stress,
Hypertension, Hypothalamic-pituitary-adrenal axis, Memory, Renin-angiotensin
system, Sympathoadrenal axis.
Affiliation:
Departamento de Ciencias Fisiologicas, Faculdade de Odontologia de Piracicaba Av. Limeira, 901 - Piracicaba, SP - Brazil CEP 13414-903.
