Abstract
The effect of hemorheologically active agents. denbufylline, pentoxifylline and Zy 16075 were compared on total blood viscosity in vitro. A rotational Contraves Low Shear 30 viscometer was used for measurement. The results showed that these agents were capable of decreasing rat arterial and venous total brood viscosity, the potency being the order of: denbufylline > Zy 16075 > pentoxifylline, in EDTA-anticoagulated rat arterial blood. However, none was effective in human venous blood. The lack of effect in human venous blood was not due to a specific anticoagulant, Since the absence of effectiveness was evident when EDTA, citrate or heparin was used. Although mechanism(s) remains unknown, the present study has demonstrated that unstressed human venous blood from healthy volunteers is not suitable for detecting a blood viscosity reducing agent, whereas arterial rat blood might be a good tool for detecting such agent.