[Effect of hypotension on the arterial system responsiveness]

The correlation analysis revealed no correlation within the range 110 to 80 mm Hg further transforming into a direct (within the range lower than 80 mm Hg) dependence of the pressure responses to mesatone on the reduction of initial mean arterial pressure under orthostatic hypotension in anaesthetised rats. Under paraverine hypotension a reverse correlation within the range 110-80 mm Hg transforming into a direct dependence (within the range lower than 80 mm Hg) of the responses to mesatone were observed. The dependence of cardiac shifts to mesatone on the initial arterial pressure was not occurred. The mechanisms of dependence of the systemic vascular responses on initial tone of arterial vessels, are discussed.