Desensitization of tachykinin NK
(A and B) and NK
(C and D) receptors. Human bronchi were pre-treated with SR 48968 (10-7 M) (A and B) or SR 140333 (10-7 M) (C and D) before cumulative or non cumulative additions of hHK-1 (B and D, n = 5), [Sar9,Met(O2)11] SP (A, n = 10) or NKA (C, n = 5). Experiments were performed in the presence of phosphoramidon (10-6 M). Values are expressed in percentage (mean ± s.e.m.) of maximal contraction obtained with ACh 3 mM.