Garlic Powder Effect on Plasma Renin Activity, and Cardiovascular Effects of Intravenous Angiotensin I and Angiotensin II in Normotensive and Hypertensive Male Rats

Background: Hypertension is amongst major health issues in developed countries, which results in cardiovascular morbidity and mortality. Garlic plays an important role in the reduction of hypertension. Objectives: The aim of the this study was to investigate the effect of consumption of garlic powder on blood pressure and renin angiotensin system in a nitric oxide deficiency hypertension model in male rats. Materials and Methods: In this study, thirty-two adult male Wistar rats (200 - 250 g) were randomly divided to four groups as follows: normotensive, normotensive-garlic, hypertensive and hypertensive-garlic. Oral N-nitro-L arginine methyl ester (L-NAME) was used to induce hypertension. Normotensive-garlic and hypertensive-garlic groups were fed 900 mg of garlic powder daily by oral gavage for forty-five days. At the beginning of the experiments, systolic blood pressure was measured. Immediately after the end of the experimental procedure animals were anaesthetized by pentobarbital, blood samples were collected and, after injection of angiotensin I, angiotensin II and captopril, blood pressure was re-measured. Plasma renin activity was also measured. Results: At the beginning and at the end of experiments, systolic blood pressure was higher in the hypertensive groups than the normotensive group. However, at the end of the study, diastolic blood pressure and mean arterial pressure were higher in the hypertensive groups than the normotensive group. Angiotensin I level was low in the normotensive group whereas plasma renin activity was high in the hypertensive group. After different doses of injection of angiotensin I and angiotensin II, mean arterial pressure was significantly increased in the normotensive-garlic and the hypertensive-garlic groups, respectively. By using captopril, mean arterial pressure and its changes were not significant after injection of different doses of angiotensin I in different groups. Conclusions: Garlic powder consumption can reduce blood pressure, yet in this model, it did not have an effect on the interaction between renin angiotensin system and nitric oxide inhibition.