| Abstract: | Experiments were carried out to study the effect of sydnocarb 3-(beta-phenylisopropyl)-N-phenylcarbamoyl-sydnonimine), a stimulant of mental and physical performance, and its combination with obsidan, a beta-adrenoblocking agent, on the central and peripheral hemodynamics during a head-up test (+75 degrees) after a 6-hour head-down tilt (-15 degrees). Sydnocarb increased the tone of brain and leg arterioles, left unchanged stroke volume and cardiac output, and decreased the postural increment of heart rate. Sydnocarb (15 mg) combined with obsidan (20 mg) reduced heart rate and its postural increment, increased stroke volume, and increased the tone of resistive vessels, as was also the effect of sydnocarb taken separately. |
