[Studying the Persistence of Blood Flow Oscillations in Rat Kidneys]

This work was designed to study the nonlinear dynamics of fluctuations in renal blood flow of rats under basal conditions and in the perturbed state. An intramuscular injection of aspirin in 0.9% physiological saline (0.5 mg per 100 g body weight) served as a perturbation factor. Capillary blood flow in the right kidney of a rat was measured by the method of laser Doppler flowmetry. The persistence of these time series was estimated by the Hurst method. Our study revealed the persistence of time series under basal conditions (Hurst index H = 0.817 ± 0.041). Statistical parameters of the perturbed series were shown to differ significantly from those observed in the initial state. However, the perturbed series remained persistent. The Hurst index for these series was H = 0.677 ± 0.057. A decrease in this index was insignificant (as compared to that for the baseline index).