Tachykinin activation of human monocytes from patients with interstitial lung disease, healthy smokers or healthy volunteers

'Three types of tachykinin receptors, NK1, NK2 and NK3, have been described to preferentially interact with substance P (SP), neurokinin A (NKA) and neurokinin B (NKB) respectively. Experimental evidence indicates that SP and NKA modulate the activity of inflammatory and immune cells, including mononuclear ones, and points to their involvement in lung pathophysiology. We previously reported that NK1 and NK2 receptors are present on monocytes (MO) isolated from healthy donors or rheumatoid patients - a greater sensitivity to NK2 receptor stimulation was observed in the latter condition. This study evaluated the effects of SP and NKA, as well as NK1 and NK2 selective agonists and antagonists, on MO obtained from healthy volunteers, healthy smokers or patients with interstitial lung diseases (e.g. sarcoidosis and idiopathic pulmonary fibrosis). Superoxide anion (O-2(-)) production was chosen as a parameter of cell activation. SP and NKA dose-dependently evoked O-2(-) production from MO in all the conditions evaluated, their effects being competitively antagonized by selective antagonists (CP 96 345 and MEN 10 627, respectively). When selective NK1 and NK2 agonists were used, [Sar (9)Met(O-2)(11)]SP, a selective NK1 agonist, induced a more than doubled O-2 production in MO obtained from patients with interstitial lung diseases as compared to healthy volunteers, whereas MO isolated from healthy volunteers were more sensitive to NK2 receptor stimulation. (C) 2000 Harcourt Publishers Ltd.