Priming effects of mammalian tachykinins on human neutrophils.

The undecapeptide substance P (SP) is known to activate different cell types involved in inflammatory and immune processes. By evaluating primed stimulation of human neutrophils, we now demonstrate that SP (10 nM-0.1 mM) dose-dependently enhances superoxide anion production from cells stimulated by the phospholipid mediator Platelet Activating Factor (PAF). We also provide evidence that neurokinin A (NKA), which is released, as well as SP, from C fibers of sensory nerves, potentiates PAF-evoked superoxide anion generation, while neurokinin B (NKB) is ineffective.