Figure 2: Uterus-relaxant effects of nociceptin (N/OFQ) and nocistatin (NST) on the term- and preterm-pregnant human myometrium in vitro. The contractions were elicited with 10-8 M oxytocin in uterine rings from full-term (A, B) and preterm (C, D) human pregnancies. A) The concentration-dependent relaxing effect of N/OFQ (▲) was significantly increased in the presence of NST (10-8 M; Δ); n=6. B) The concentration-dependent relaxant effect of NST (●) was not altered by N/OFQ (10-8 M; ○); n=4. C) The concentration-dependent relaxing effect of N/OFQ (▲) was significantly increased in the presence of NST (10-8 M; Δ); n=4. D) Co-administration of N/OFQ (10-8 M) with NST (○), however, did not significantly alter the uterus-relaxant effect of NST (●); n=5.