Antihypertensive Effect of Valoneic Acid Dilactone on Fludrocortisone Induced Hypertensive Rats

Objective: This study evaluated the possible protective effect of valenoic acid dilactone on fludrocortisones induced hypertension in Wister rats. Methodology: Fludrocortisones induced reabsorption of salt and water leading to increase in blood volume and hence, increase blood pressure. There is also increased secretion of vasopressin in addition, altered activity of renninangiotensin-aldosterone system (RAAS) leading to increase in sympathatic activity. Valoneic acid dilactone at dose 400 mg kgG1 dayG1 p.o. for 3 weeks was evaluated for its effect on blood pressure and heart rate using non-invasive blood pressure measuring apparatus. Vascular reactivity experiments were performed in segments of aorta from normotensive rats, hypertensive control rats and hypertensive rats treated with valoneic acid dilactine. Results: Treatment with valoneic acid dilactone significantly reduced the blood pressure of fludrocortisones salt-treated hypertensive rats. Valoneic acid dilactone administered to normotensive rats for 3 weeks did not alter the mean blood pressure and heart rate. The vascular reactivity to noradrenaline (8.47×10G7 to 1.73×10G4) in isolated aortic strip was increased in fludrocortisone salt-treated hypertensive rats. The contractile responses to noradrenalin in isolated aortic strip from hypertensive rats treated with valoneic acid dilactone were significantly reduced than that in the controls. Conclusion: The present in vivo and in vitro studies have shown, that there is increase in vascular reactivity to adrenaline in fludrocortisones salt-treated hypertensive rats. The reduction in vascular reactivity by valoneic acid dilactone suggests that there is alteration in the sensitivity of the adrenoceptor to noradrenalin and adrenaline. Valoneic acid dilactone shows antihypertensive activity in fludrocortisone salt-treated hypertensive rats.