Diminished response of isolated aorta following chronic physical and psychological stresses and its reversibility in rats

Abstract

Background: The role of stress has been elucidated in cardiovascular disorders. The aim of this study was to determine and compare the effects of chronic physical and psychological stress on the contractility of isolated rat aorta and their reversibility. Materials and Methods: Wister rats were divided into 3 groups: control, physical stress, and psychological stress (n = 12). Animals were kept on 12-h/12-h light/dark cycles at 22 ± 2oC and had free access to food and water. Physical and psychological stress was induced using a communication box for 3 weeks. Physical stress was applied with electrical current (1 mA, 1 Hz, 10 sec/min) 1 hour twice daily. To assess the aortic response, the animals were anesthetized, abdominal aortas were removed, and the contractility response to potassium chloride and phenylephrine was measured with an isometric transducer. To study the reversibility of the effects, separate groups of stressed animals and a control group (n = 12 in each group) were kept for 1 month following the stress period, and the aortic responses were evaluated and compared. Results: In the stressed group, the aortic responses to potassium chloride and phenylephrine were significantly lower compared with the controls, whereas the corticosterone concentration was higher. Following a 1-month recovery, both values returned to normal. Conclusions: Chronic physical stress and psychological stress have similar effects on vascular responsiveness, which are reversible; these findings may be clinically important in the treatment of stress-related cardiovascular disorders. © 2012 Kowsar M. P. Co.