The Effects of Different Salt Loadings on Baroreflex Sensitivity in Two-Kidneys One-Clip Hypertension

Purpose: In the present study, we aimed to investigate the effects of low salt (0,5 % NaCl) and high salt (% 1 NaCl) loadings on baroreflex sensitivity and PRA in 2K-1C hypertensive rats. Material and Methods: Distilled water or low salt loading or high salt loading was given, as drinking water, to the rats from both clipped and their sham operated control groups for 3 weeks. Then, PRA, blood pressure levels and arterial baroreflex sensitivity with its parasympathetic component were measured by using pheylephrine and sodium nitroprussid in the conscious rats. The sensitivity of sympathetic component of baroreflex was calculated from total and parasympathetic sensitivity. In addition, basal and intrinsic heart rates, cardiac and renal weights were measured. Results: Clipping increased PRA under distilled water intake and high salt loading conditions (p<0,05). PRA decreased in clipped rats under low salt while in controls under high salt loadings (p<0,05). The sensitivity of baroreflex was decreased only in clipped rats under distilled water intake (p<0,05). Salt loadings did not affect baroreflex sensitivity neither between clipped nor between control groups but led to dissapear the difference between clipped and control rats. The parasympathetic component of baroreflex was decreased only under high salt loading (for bradycardic response, p<0,05 and for tachycardic response, p=0,05). Clipping increased blood pressure (p<0,01) and left heart weight (p<0,05) under all salt intake conditions. Salt loading did not affect blood pressure and left heart weight in clipped rats. Conclusions: We can conclude that salt loading led to disappear the decrease in baroreflex sensitivity of two kidney one clip hypertensive rats, probably by suppressing the renin angiotensin system activity. In addition, the salt-induced effect on baroreflex sensitivity did not prevent the clipping-induced blood pressure increase in this hypertension model.