Objective: Chronic NOS inhibition-induced hypertension model is used commonly in essential hypertension researches. All these studies investigated using a stable doses of NOS inhibitor agents over experimental progress. But, it is decreased gradually synthesis and/or release of NO in essential hypertension. To better mimic essential hypertension, the doses of L-NNA (a NOS inhibitor) was administrated gradually increasing and was compared group of stable dose.

Material and Method: Wistar rats were divided into 3 groups. Control group was done any administration. Second group took the stable concentration of L-NNA over 3 weeks and third group took gradually increasing concentration of L-NNA for 3 weeks. Blood pressure and heart rate are measured by tail-cuff method. Plasma nitrite/nitrate levels and kidney/body weigth ratios were also compared.

Results: In the stable dose administrated group, heart rates decreased while the blood pressure increased. On the other hand, in the gradually increasing doses of L-NNA administrated group, heart rates did not change despite the increasing blood pressure. Plasma nitrite/nitrate levels decreased significantly but there was any change in kidney/body weight indexes in groups.

Conclusion: It is suggested that is associated more gradually NOS inhibition than stable NOS inhibition with essential hypertension. ©2007, Fırat Uiversity, Medical Faculty