Evaluation of enalapril affecting the renin-angiotensin system in normal and stress-induced rats based on urinary metabolites of amines and cortisol

INTRODUCTION: The renin-angiotensin system is distributed centrally as well as peripherally, which works in association with SNS and HPA in stress. Angiotensin is considered one of the principal hormones for bringing out stress-related changes. To find the influence of enalapril on the neuromediator of CNS and periphery, the present work was carried out. The assessment of the transmitter levels was done by estimating major urinary stress metabolites like vanillylmandelic acid, 5-hydroxyindoleacetic acid, 6-β-hydroxycortisol and homovanillic acid in normal and stress-induced conditions and also in the absence and presence of enalapril treatment in rats. MATERIALS AND METHODS: Groups of rats were subjected to a forced swim stress one hour after daily treatment of enalapril. The 24 h urinary excretion of vanillylmandelic acid, 5-hydroxyindoleacetic acid, 6-β-hydroxycortisol and homovanillic acid was determined in all groups under normal and stressed-induced conditions. RESULTS: Daily administration of enalapril at doses of 3, 10 and 30 mg/kg/body weight inhibited the stress-induced urinary biochemical changes. However, treatment with enalapril in normal conditions increased the excretion of all selected metabolites. CONCLUSION: It can be speculated that enalapril prevented stress-induced increases of adrenergic, serotonergic and cortical mechanisms.