Figure 6.

Cilostamide (300 nmol·L⁻¹, Cil) disclosed ventricular 5-HT responses in newborn piglets (A) but not in adolescent pigs (B). 5-HT enhances ventricular force in the presence of concurrent rolipram (1 µmol·L⁻¹, Rol) + cilostamide in both newborn piglets (A) and adolescent pigs (B). Basal force and force in the presence of (-)-isoprenaline (200 µmol·L⁻¹, ISO) were 2.7 ± 0.5 and 10.0 ± 1.7 mN, respectively, in newborn (28 trabeculae from 20 piglets), and 2.5 ± 0.5 and 10.1 ± 1.1 mN in adolescents (28 trabeculae from 10 pigs). *P < 0.05 with respect to absence of rolipram. Open and closed columns summarize data in the presence and absence of 5-HT (10 µmol·L⁻¹).