Histamine Disposition in Endothelial Specific Granules of the Toad Aorta

Abstract

High-performance liquid chromatography revealed that toad aorta delivered appreciable concentrations of histamine into the perfusate when perfused by Ringer’s solution containing the histamine liberator. Electron micrographs of this vessel after the perfusion showed an expulsion of the endothelial specific granules into the vascular lumen. These results support to our previous hypothesis that the granules are a reservoir site of histamine and might take an important role in the regulation of vascular tone.

Histamine release from Weibel‐Palade bodies of toad aortas induced by endothelin‐1 and sarafotoxin‐S6b

“…Few or no gold particles are seen in the endothelial cell (EC) perfused with a n OR-2 solution only in which normal antihistamine sera were replaced by normal rabbit sera for the negative staining. x 23,000. the perfusate using HPLC (Fujimoto, 1982;Fujimoto et al, 1984). Also, we reported that both ET-1 and STX-S6b induce ultrastructural changes of the WP bodies.…”

“…Our previous chromatographic studies suggested the presence of histamine in WP bodies in the endothelial cells of both the toad aortas (Fujimoto, 1982a;Fujimoto et al, 1984) and the rabbit umbilical vein (Fujimoto et al, 1982b). After treatment with compound 48/80, a liberator of histamine, WP bodies of the toad aortas show a remarkable degranulation, and a n appreciable concentration of histamine was assayed from the perfusate (Fujimoto et al, 1984). This suggests that WP bodies are a storage site of histamine.…”

Titel

“…Earlier studies have detected histamine in rat aortic endothelial and subjacent smooth muscle cells, but not the enzyme itself [6]. Histamine has also been detected in human umbilical vein endothelial cells [7] and localized in aortic endothelial cell granules of the toad [8]. HDC activity has been demonstrated indirectly in aortic segments from rabbits [9] and bovine aortic endothelial cells [10].…”