Tactile stimulation of adult rats modulates hormonal responses, depression-like behaviors, and memory impairment induced by chronic mild stress: Role of angiotensin II

• Published in: Behavioural brain research 2020-02, Vol.379, p.112250-112250, Article 112250
• Main Authors: Costa, Rafaela, Tamascia, Mariana Leite, Sanches, Andrea, Moreira, Roseli Peres, Cunha, Tatiana Sousa, Nogueira, Marie Doki, Casarini, Dulce Elena, Marcondes, Fernanda Klein
• Format: Article
• Language: English
• Subjects: Angiotensin II - metabolism; Angiotensin II Type 1 Receptor Blockers - administration & dosage; Angiotensin II Type 1 Receptor Blockers - pharmacology; Animals; Behavior, Animal - physiology; Cognitive Dysfunction - etiology; Cognitive Dysfunction - therapy; Depression; Depression - etiology; Depression - physiopathology; Depression - therapy; Handling, Psychological; Hypothalamus - drug effects; Hypothalamus - metabolism; Learning; Losartan - pharmacology; Memory; Memory Disorders - etiology; Memory Disorders - therapy; Physical Stimulation; Rats; Rats, Sprague-Dawley; Stress; Stress, Psychological - complications; Stress, Psychological - metabolism; Stress, Psychological - therapy; Tactile stimulation; Touch - physiology
• ISSN: 0166-4328; 1872-7549
• DOI: 10.1016/j.bbr.2019.112250

•Chronic mild unpredictable stress increased depressive-like behavior.•Chronic mild unpredictable stress induces cognitive impairment.•Chronic mild unpredictable stress increased hypothalamic angiotensin II.•Handling and losartan cancelled behavior responses induced by stress.•Handling and losartan decreased and cancelled respectively stress-induced hypothalamic angiotensin II secretion. Physical touch can help to decrease the effects of stress. The aim of this study was to evaluate the influence of tactile stimulation on the hormonal and behavioral responses of young adult rats submitted to chronic mild unpredictable stress (CMS), considering the role of angiotensin II (Ang II). In Experiment 1, male rats were divided into 4 groups: control, stress, tactile stimulation (TS), and stress + TS. CMS was applied for three weeks. Tactile stimulation was applied for seven weeks, five days a week. After the CMS protocol, depression-like behaviors were evaluated by forced swimming and sucrose consumption tests. Learning and memory were evaluated using the Y-maze test. Fifteen days after the CMS procedure, the animals were euthanized and the levels of stress hormones were determined. The hypothalamus was isolated for determination of the Ang II concentration. In Experiment 2, control and stressed rats, with or without treatment using losartan (angiotensin II type 1 receptor blocker), were evaluated using the same behavioral tests and the hypothalamus Ang II concentration was also determined. CMS increased plasma corticosterone, norepinephrine, and epinephrine concentrations, induced depression-like behaviors, impaired learning and memory, and increased the Ang II concentration in the hypothalamus. Tactile stimulation attenuated these stress-induced effects. Losartan treatment effectively prevented increase of the hypothalamic Ang II concentration and the development of depression-like behavior, and also reduced the impairment of learning and memory in the stressed animals. The results indicated that tactile stimulation seemed to protect adult rats against hormonal and behavioral chronic stress effects, and that Ang II could be involved in the CMS effects.