Action of histamine on endothelial cells of guinea-pig isolated hepatic portal vein and its modification by indomethacin or removal of calcium.

Methods are described for preparing guinea-pig hepatic portal vein endothelium for light microscopy and electron microscopy. Histamine (100 mug/ml) caused damage to the endothelium which was visible with both the light and electron microscopes. The damage was reduced in the absence of calcium. The reduction was more apparent with the electron microscope than with the light microscope. Indomethacin (100 mug/ml) protected the endothelial cells against the damaging effects of histamine. Possible modes of action of histamine and indomethacin are discussed.