Long-term dynamics of blood pressure in intact and sympathectomized post-suspension rats

Low-frequency dynamics of mean arterial pressure (MAP) and pulse interval (PI) was studied in intact and sympathectomized rats after 2-week tail suspension. Correlation properties of long-term (f<0.8 Hz) MAP fluctuations were analyzed using R/S Hurst method. It was shown that time series of successive increments in MAP level display power-law fractal anticorrelations in wide range of time scales. After sympathectomy and/or suspension averaged Hurst exponents were more close to the value for uncorrelated random process (H=0.5), indicating deterioration of regulatory feedbacks. Besides, a decrease of coherence between MAP and PI in low-frequency range was observed after suspension in both intact and sympathectomized rats, indicating alteration of non-sympathetic cardiovascular control mechanisms.