Fig. 6. Responses to uridine 5'-triphosphate (UTP) in stomach muscle preparations. (A) Concentration-dependent response of mean force to UTP. A statistically significant decrease was obtained at 10 µmol l^–1 in prometamorphosis (N=9) and in juvenile tissues at 1000 µmol l^–1 (N=12). In metamorphic tissues a significant increase was obtained at 30 µmol l^–1 (N=6). Control value prior to administration of agonist is denoted C on the x-axis. Statistical analysis was performed using repeated measures one-way ANOVA followed by Dunnett's post hoc test. (B–D) Representative traces of the response to UTP in (B) prometamorphic tissues, (C) metamorphic tissues and (D) juvenile tissues (concentrations in µmol l^–1).