Recent advances in the research of lymphatic stomata.

Lymphatic stomata are small openings of lymphatic capillaries on the free surface of the mesothelium. The peritoneal cavity, pleural cavity, and pericardial cavity are connected with lymphatic system via these small openings, which have the function of active absorption. The ultrastructure of the lymphatic stomata and their absorption from the body cavities are important clinically, such as ascites elimination, neoplasm metastasis, and inflammatory reaction. The lymphatic stomata play an important role in the physiological and pathological conditions. Our previous study indicated for the first time that nitric oxide (NO) could regulate the opening and absorption of the lymphatic stomata. It could decrease the level of free intracellular calcium [Ca(2+)] through increasing the cyclic guanosine monophosphate (cGMP) level in the rat peritoneal mesothelial cells, thus regulating the lymphatic stomata. This process is related with the NO-cGMP-[Ca(2+)] signal pathway. In this review, we summarize the recent advances in understanding the development and the function of the lymphatic stomata. The ultrastructure and regulations of the lymphatic stomata are also discussed in this review.