Proatherosclerotic effects of chronic stress in male rats: Altered phenylephrine sensitivity and nitric oxide synthase activity of aorta and circulating lipids

Abstract

The aim of this study was to analyze the effects of chronic mild unpredictable stress (CMS) on the vasoconstrictor responseand morphology of the thoracic aorta and serum lipid profiles in rats. Male Sprague–Dawley rats were submitted to CMS,which consisted of the application of different stressors for 7 days per week across 3 weeks. The rats were sacrificed 15 daysafter CMS expsoure. CMS induced supersensitivity to the vasoconstrictor effect of phenylephrine in endothelium-intactthoracic aortic rings without changes in aortic rings without endothelium, or pre-incubated with nitric oxide (NO) synthesisinhibitor. Rats submitted to CMS showed hypertrophy of the intima and tunica media of thoracic aorta, increased serum levelsof triglycerides, total cholesterol, very low-density lipoprotein cholesterol, low-density lipoprotein cholesterol and atherogenicindex, without changes in high-density lipoprotein cholesterol levels, when compared with control rats. These data indicatethat CMS induces physiological and morphological changes that may contribute to the development of atherosclerosis bymechanisms related to deficiency in NO production and dyslipidemia