Habituation of the cardiovascular responses to restraint stress is inhibited by exposure to other stressor stimuli and exercise training

Abstract

This study evaluated the effect of exposure to either a chronic variable stress (CVS) protocol or social isolation, as well as treadmill exercise training, in the habituation of the cardiovascular response upon repeated exposure to restraint stress in rats. The habituation of the corticosterone response to repeated restraint stress was also evaluated. For this, animals were subjected to either acute or 10 daily sessions of 60 min of restraint stress. CVS and social isolation protocols lasted for 10 consecutive days, whereas treadmill training was performed for 1 h per day, 5 days per week for 8 weeks. We observed that the increase in serum corticosterone was reduced during both the stress and the recovery period of the 10th session of restraint. Habituation of the cardiovascular response was identified in terms of a faster return of heart rate to baseline values during the recovery period of the 10th session of restraint. The increase in blood pressure and the decrease in tail skin temperature were similar at the 1st and 10th session of restraint. Exposure to CVS, social isolation or treadmill exercise training inhibited the habituation of the restraintevoked tachycardia. Additionally, CVS increased the blood pressure response at the 10th session of restraint, whereas social isolation enhanced both the tachycardia during the first session and the drop in skin temperature at the 10th session of restraint. Taken together, these findings provide new evidence that pathologies evoked by stress might be related to impairment in the habituation process to homotypic stressors.

Spontaneous recovery, time course, and circadian influence on habituation of the cardiovascular responses to repeated restraint stress in rats

“…This pattern of habituation is such different from those identified for the cardiovascular responses. Similar to that recently documented [1,2], our study showed that habituation of the cardiovascular responses to restraint could be observed mainly in terms of a faster return of HR and MAP to baseline values during the recovery period from the restraint stress. However, the values during the tenth session were similar to those observed during the acute restraint session.…”

“…However, the values during the tenth session were similar to those observed during the acute restraint session. Taken together, the corticosterone and cardiovascular responses to stress indicate that habituation may be system specific rather than a generalized body response [2].…”

Role of angiotensin receptors in the medial amygdaloid nucleus in autonomic, baroreflex and cardiovascular changes evoked by chronic stress in rats

“…This habituation process is proposed as a adaptative mechanism that limit the consequences of chronic stress (Bennett et al., 2018; Grissom & Bhatnagar, 2009; Herman, 2013; McCarty, 2016). However, recent evidence indicated that habituation of the cardiovascular changes to restraint stress is less pronounced in relation to, for instance, the HPA axis response (Benini et al., 2020; Santos et al., 2020). Accordingly, several cardiovascular changes have been reported following repeated exposure to restraint stress, including increase in arterial pressure (Bruder‐Nascimento et al., 2012, 2015; Duarte et al., 2015b; Duarte, Planeta, et al., 2015; Habib et al., 2015; Yang et al., 2014), without changes in HR (Daubert et al., 2012; Duarte et al., 2015b; Duarte, Planeta, et al., 2015).…”

Lateral hypothalamus involvement in control of stress response by bed nucleus of the stria terminalis endocannabinoid neurotransmission in male rats

“…The animals were maintained for a period of 60 min into the restraint tube 5 , 13 , 27 . Each animal was submitted to only one session of stress in order to avoid habituation 61 – 63 .…”