Journal of Clinical & Experimental Pharmacology

Influence of age and type of aversive stimulus in cardiovascular consequences of chronic emotional stress: Role of autonomic and vascular mechanisms

World Congress on Pharmacology

July 20-22, 2015 Brisbane, Australia

Carlos C Crestani

Posters-Accepted Abstracts: Clin Exp Pharmacol

Abstract:

Several lines of evidence correlate psychosocial factors with the pathogenesis of cardiovascular diseases. Adolescence has been proposed as an ontogenic period of vulnerability to stress. Nevertheless, the impact of stressful events during adolescence in cardiovascular activity is poorly understood. In the present study we investigated the impact in cardiovascular function of adolescent and adult rats of two chronic stress protocols: the repeated restraint stress (RRS) and chronic variable stress (CVS). Also, the long-lasting effects in adulthood of stressful events during adolescence were investigated. CVS increased blood pressure and heart rate regardless of the age, whereas RRS increased blood pressure selectively in adults. Assessment of the cardiac autonomic tonus realized by intravenously administrating methyl atropine (muscarinic receptor antagonist) and propranolol (?-adrenoceptor antagonist) revealed that CVS-evoked resting tachycardia was associated with increased cardiac sympathetic activity in adults while a decreased cardiac parasympathetic activity was observed in adolescent animals. RRS also decreased cardiac parasympathetic activity in adolescents, but this effect was followed by a reduction in intrinsic heart rate. Analysis of vascular reactivity to vasoactive agents indicated that both stress regimens increased the vasoconstrictor response to the ?1-adrenoceptor agonist phenylephrine in adolescent animals. Also, results indicated that RRS, but not CVS, reduced the vasodilator response to acetylcholine and the nitric oxide donor sodium nitroprusside in both adolescent and adult animals. All alterations observed during adolescence were reversed in adulthood. These findings indicate an age- and stress type-specific influence in stress-evoked cardiovascular/autonomic changes. Moreover, data suggest absence of cardiovascular consequences in adulthood of stress during adolescence.