Ruthenium-red-stained polyanionic fixed charges in peritoneal microvessels.

This study shows that the luminal surface of peritoneal microvascular endothelium, coated pits and coated vesicles are all negatively charged, unlike the limiting membrane of pinocytotic vesicles and transcellular channels. Our findings suggest that these cellular organelles have different functions as well as a different chemical composition. Anionic sites were observed along the subendothelial and subperithelial basal laminae of peritoneal capillaries and post capillary venules, respectively. Electric charge is a new parameter to be considered when analyzing transperitoneal transfer of charged macromolecules.