[Effects of two-week suspension on the dynamics of low-frequency arterial pressure fluctuations in intact rats and rats after sympathectomy].

Spectral analysis was used to study the dynamics of low-frequency hemodynamic fluctuations in male Wistar rats following 2-wk tail-suspension. The experiment was performed with intact rats and rats with the sympathetic nervous system damaged by 6-hydroxidofamine injection. Equally in intact and desympathetized animals, low-frequency fluctuations of arterial pressure (AP) were found less intensive within the 0.1 Hz region during and immediately after suspension. Beyond that, the intact rats exhibited decreases in the AP fluctuations coherence and pulse interval in this spectral region. Results of the investigation indicate that simulated gravitational unloading of rats produces changes in the dynamics of the low-frequency AP fluctuations; however, some part of these changes are not controlled by the sympathetic nervous system.