Prostacyclin release induced by neurokinins in cultured human endothelial cells
The effects of neurokinins (NK) and related peptides on the secretion of 6-keto-prostaglandin F1α, a stable metabolite of prostacyclin, were measured. These peptides enhanced three- to five-fold the basal secretion rate with the following rank order of potency (based on threshold concentrations for a significant output): substance P (SP) ≥ NKA > SP 4–11 ≥ [pGlu6]SP 6–11 = SP7–11. NKB and SP 1–9 were inactive. Ac[Arg6, Sar9, Met(O2)11]SP, a NK1 receptor selective agonist, was more potent than other selective agonists for the NK2 and NK3 receptor subtypes. These results suggest that the NK receptors, which mediate the release of prostacyclin from human endothelial cells, belong to the NK1 subtype.Key words: neurokinins, substance P fragments, selective agonists, prostacyclin release, human endothelial cells.