Stress-induced subsensitivity to catecholamines depends on the estrous cycle

Abstract

In this article we compare how sensitivity to the chronotropic effect of noradrenaline and adrenaline of right atria isolated from female rats is modified after repeated swimming or foot-shock stress, under the influence of the estrous cycle. Right atria from stressed female rats sacrificed at diestrus were subsensitive to both catecholamines, irrespective of the stressor agent. However, although subsensitivity to noradrenaline was of similar intensity, subsensitivity to adrenaline was more pronounced in right atria from foot shock stressed rats as opposed to swimming-stressed rats. Identical stress protocols did not induce any alteration in atrial sensitivity to catecholamines when the stressed female rats were sacrificed at estrus. We conclude that the stress reaction concerning the mediation of cardiac chronotropism by catecholamines is related to the severity of the stressor agent and is strongly influenced by the estrous cycle.

Aspectos moleculares, funcionais e comportamentais envolvidos nas alterações metabolicas desencadeadas pelo estresse

“…Similar results have been obtained for cardiac tissue isolated from rats exposed to the same stressor agent 3,4 .…”

“…Adipocytes 2 and cardiac tissue 3,4 obtained from foot shock stressed rats show supersensitivity to ISO, EPI and TA2005 that is abolished by the β 2-AR antagonist ICI118,551. The supersensitivity to non-selective β-AR agonists or selective agonists for β 2 -AR is also abolished by treating the rats with RU38484, a compound that blocks the glucocorticoid receptor, before exposure to stress 7 .…”

The comparison of immobility time in experimental rat swimming models

“…Swimming is an experimental protocol used for inducing stress in laboratory rodents (Marcondes et al, 1996;Barros and Ferigolo, 1998;Tanno et al, 2002). In these studies, some of the biochemical, hormonal and behavioral changes are recorded to evaluate the animal's physiological responses to a stressful situation (De Boer et al, 1990;Bruner and Vargas, 1994;Marcondes et al, 1996;Tanno et al, 2002).…”

“…In these studies, some of the biochemical, hormonal and behavioral changes are recorded to evaluate the animal's physiological responses to a stressful situation (De Boer et al, 1990;Bruner and Vargas, 1994;Marcondes et al, 1996;Tanno et al, 2002). When a swimming session begins, the rats swim actively and afterwards they become less active and immobility is observed.…”

Contribution of Catecholamine Reactive Intermediates and Oxidative Stress to the Pathologic Features of Heart Diseases

“…Regardless of the general notion that the response to stress is primitive and unspecific, currently it is accepted that each stressor unchains its own neurochemical profile [9]. Differentiated responses in the sympathetic nervous and adrenomedullary hormonal systems occur depending on the type and intensity of the stressor, how it is sensed by the organism and interpreted in light of previous experiences [301,302]. However, catecholamine-induced contraction-band necrosis has been observed post-mortem in human subjects who died under terrifying circumstances such as fatal asthma [303] and violent assault [304], suggesting that elevated levels of catecholamines may be an important link between emotional stress and cardiac injury [285].…”