The Effect of Unilateral Nephrectomy on Arterial Blood Pressure Variability in Spontaneously Hypertensive Rats

Abstract

The aim of the current study was to investigate the effects of unilateral nephrectomy (ULN) on fast oscillation of arterial blood pressure in spontaneously hypertensive rats (SHR). Experiments were carried out on conscious normotensive Wistar rats and SHR divided in groups with intact kidneys: W, n = 10; SHR, n = 9 and with unilateral nephrectomy: WN, n = 10; SHRN, n = 10. ULN was performed under general anaesthesia (Nembutal 35 mg/kg b.w. i.p.), eight days before the experiments. Blood pressure variability was investigated by means of spectral analysis of systolic (SAP) diastolic (DAP) and mean (MAP) arterial blood pressure, estimated in directly registered arterial blood pressure wave. In SAP, DAP and MAP spectrograms, derived by Lab View software equipment, the spectral power (P) in low (LF, 20–195 mHz), mid (MF, 195–605 mHz) and high frequency (HF, 605—3000 mHz) bands was calculated. PLF in SAP spectrograms increased after ULN both in Wistar rats and SHR. ULN led to decrease of PMF in SAP, DAP and MAP spectrograms only in SHR. The ULN provokes changes in blood pressure variability in different manner in the normotensive and the spontaneously hypertensive rats. In addition to humorally-mediated low-frequency oscillations, ULN in SHR also af- fected the spectral characteristics of the arterial pressure in which sympathetic nervous activity operates.