Possible Mechanisms for Normalization of the Level of Arterial Pressure with Unilateral Vasorenal Hypertension

Abstract

The purpose of the study is on the model of vasorenal hypertension (2 kidney, 1 clamp) to study the dynamics of heart rate variability (HRV) spectrum components depending on stability of hypertension, developed after renal artery clamping. Experiments were put on Wistar male rats. During experiments in awake animals conducted registration systolic blood pressure (SBP), beat-to-beat interval (RR), spectral analysis of HRV. 1-3 weeks after the clipping of the renal artery, an elevation of MAP was observed in 21 of 33 rats. However, by week 8 of observations, the level of SBP was normalized in 11 animals. Analysis of the parameters studied in animals in which, after applying a clamp to the renal artery, an unstable elevation in the SBP was registered, showed a decrease in the high-frequency component (HF) of the HRV spectrum with an increase in the SBP. Normalization of SBP occurred within 1-5 weeks and was accompanied by restoration of HF and an increase in the length of RR. It was concluded that with unilateral ischemia of the kidneys, including mechanisms that positively affect the tone of the vagus, which counteracts the rise in blood pressure and promotes the normalization of its level, are activated.