抄録
The lymphatic system plays a quite important part of microcirculation. The main function of the system is drainage of body fluid that leaks out of blood capillaries into the tissues, especially plasma protein, in the physiological condition. In addition, it is known that the lymphatic system works under low oxygen condition comparing with the blood system. In the present study, we have investigated critical roles of ROS in the regulation of a heart-like lymphatic pump in vitro. Male Wistar rats (7-8 weeks old) were anesthetized with pentobarbital-Na and the afferent lymph vessels of iliac lymph nodes were isolated. The lymph vessels were cannulated with glass micropipettes and pressurized at 6 cmH2O. Changes in the diameter of the lymph vessels and frequency of the pump activity were measured by a video-microscope system. DPI (diphenyleneiodium; an inhibitor of NADPH oxidase), but not allopurinol (an inhibitor of xanthine oxidase), significantly reduced the frequency of the pump activity. The frequency of the pump activity was also significantly decreased after treatment with catalase. Exogenous application of hydrogen peroxide significantly constricted the lymph vessels. These results suggest that NADPH-derived ROS such as hydrogen peroxide may be involved in the regulation of lymphatic pump activity. [J Physiol Sci. 2008;58 Suppl:S190]
