Endothelial cells assume a central role in the one process that the permeation of microvessels is accelerated in case of inflammation. We studied the effect of histamine on endothelial permeability, [Ca2+]i, cAMP and F-actin, using same origin aortic and venular cultured endothelial monolayers. When HUVEC were treated with histamine (10(-7)-10(-5) M), permeability of FITC-dextran (molecular weight 70,000) and [Ca2+]i were increased, while cAMP content was unchanged, and F-actin content was reduced. When bovine vein-derived endothelial cells were treated with histamine, [Ca2+]i was increased via H1 receptors, but permeability and F-actin content were not altered. When human aorta-derived endothelial cells were, [Ca2+]i was increased via H1 receptors and cAMP content was increased via H2 receptors, while permeability and F-actin content were not changed. When bovine aorta-derived endothelial cells were, cAMP and F-actin content were increased, while permeability was reduced. These findings suggest that endothelial cells derived from different tissues clearly showed the different reactions to histamine, the increase in [Ca2+]i led to the increase in endothelial permeability, while the increase in cAMP levels led to the reduction in permeability, and finally, F-actin regulated endothelial macromolecular permeability.