Representative recordings of tension developed by neurokinin A (NKA) in day 18 pregnant and non-pregnant rat myometrium in the absence and presence of phosphoramidon (PPAD). NKA (100 nM) was applied to day 18 pregnant (a,b) and non-pregnant (c,d) rat myometrium in the absence (a,c) or presence (b,d) of 1 μM PPAD. PPAD was applied 10 min before and during the application of NKA. The developed tension was expressed as a percentage, assigning the values in normal (5.9 mM K+) and 40 mM K+ PSS to be 0 and 100%, respectively. The traces shown are representative of six similar independent experiments.