Substance-P-induced histamine release from human nasal mucosa in vitro

There is growing evidence that substance P (SP) is one of the main neuropeptides involved in neurogenic inflammation of the airways. However, a number of studies were not able to demonstrate histamine release from human mucosal mast cells after SP administration. Since cultures of isolated cell systems provide only a partial picture of the inflammatory processes in vivo, organ culture models promise to offer physiologically relevant assay systems for studying tissue interactions. Thus, we examined the influence of SP on histamine release and its morphological effects on human nasal mucosa using a previously described histoculture technique. Compared to controls, the histamine content in the culture bath was significantly elevated after SP stimulation (p < 0.05). Histomorphometry showed a decreased density of mast cells and an increased percentage of degranulated mast cells. These findings were dose and time dependent and support the hypothesis of a close interaction between C-sensory nerves and mast cells implying that these interactions are of pathogenetic importance in nasal mucosa inflammation.