Activation of macrophages by substance P: induction of oxidative burst and thromboxane release.

Substance P (SP), a putative neuropeptide transmitter, was examined for its effects on macrophages. Guinea-pig peritoneal macrophages were purified by adherence, challenged with SP and incubated for up to 18 h. Culture supernatants were collected to determine the release of O-2, H2O2 and TXB2. SP dose-dependently evoked O-2 and H2O2 production by C. parvum-activated macrophages and liberation of TXB2 from albumin-elicited macrophages. Generation of these proinflammatory macrophage products by SP may be relevant in the context of neuroinflammatory disease.