Effects of L-NAME, DEXA and L-NAME+DEXA on Systemic Blood Pressure of Hypertensive Pregnant and Non-Pregnant Wistar albino Rats

Abstract

Objective: NO-inhibition has no effect on blood pressure (BP) of some spontaneous hypertensive animals, but when combined with dexamethasone (DEXA), it increases BP. The study compared effects of L-NAME and/or DEXA on systemic BP of spontaneously hypertensive pregnant and non-pregnant Wistar albino rats. Method : In two simultaneous experiments 62 female rats were used. All animals were mated for 7 days. Sperm positive (n1 = 33) and negative (n2 = 29) animals were each divided randomly into 4 groups. BPs were recorded in both experiments on the 15 th day from tails indirectly, and then animals were given Physiologic Saline (Controls), L-NAME (150mg/kg/day), DEXA (100µg/kgBW/day) or L-NAME+DEXA (150mg and 100-µg per kg BW/day) for consequent 5 days. At 19 th day, BPs were measured again, before applications. Then, animals put into individual metabolic cages for 24-h urine collection. Thereafter, blood was collected under ether anesthesia, animals were euthanized and necropsied. Weights of animals (BWs), left kidneys, adrenal glands, and fetuses; food consumptions; 24-h urine volume; urinary proteins, blood glucose, and fetus numbers were determined. Data were analyzed by ANOVA and ANOVA for repeated measures. Results : In pregnant animals, L-NAME had higher BWs than DEXA and L-NAME+DEXA (P = 0.021 and P = 0.012, respectively). In non-pregnant animals, DEXA reduced BWs significantly compared with controls (P=0.042). Interventions influenced only the diastolic blood pressure of pregnant animals (P = 0.043). The difference between DEXA and L-NAME+DEXA was significant (P = 0.044). The effects of interventions on other variables varied according to whether animals are pregnant or not. Conclusion : L-NAME and/or DEXA did not influence BP in hypertensive rats.