CHANGES OF PLASMA RENIN ACTIVITY AFTER SELECTIVE NNOS SYNTHASE INHIBITION IN SPONTANEOSLY HYPERTENSIVE RATS
2011
Mileva, R., Medical University, Sofia (Bulgaria) | Marcova, P., Medical University, Sofia (Bulgaria) | Girchev, R., Medical University, Sofia (Bulgaria)
PURPOSE: The present study investigates the role of nNOS in the regulation of plasma renin activity in spontaneously hypertensive rats - SHR. METHODS: Experiments were carried out on conscious normotensive Wistar rats and on SHR. One day before experiment femoral artery for a direct arterial blood pressure ABP measurement, femoral vein for drug application and bladder for urine collection were catheterized. The ABP registration and urine collection were performed during two 40 min. periods: control period and after selective neuronal nitric oxide synthase - nNOS inhibition with 7-Nitroindazole in dose 2 mg.kg-1.h. Plasma renin activity was determined by radioimmunoassay kit - DiaSorin. The urine flow rate was measured gravimetrically; sodium concentration was determined by flame photometry. RESULTS: In SHR 7-NI decreased urine flow rate - p0.01. The nNOS inhibition did not alter ABP and sodium excretion in both experimental groups. The PRA decreased after nNOS inhibition in Wistar rats as well as in SHR but in SHR decrease of PRA was attenuated - p0.05. CONCLUSION: The role of NO, produced by nNOS in the regulation of PRA in SHR is attenuated in comparison to its role in normotensive rats. This may by a result of involving of different mechanisms responsible for hypertension
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