Figure 5.

Basal characteristics of isolated perfused heart preparations from WT and 5-HT₄-TG mice. (A) Basal force of contraction in mN. (B) Effects of agonists and antagonists on the force of contraction after 5 min (maximum was reached). (C) Basal beating rate in beats per minute (bpm). (D) Effects of agonists and antagonists on the beating rate after 5 min. Ctr, control, Iso, isoproterenol (1 µM), 5-HT, serotonin (1 µM) and 5-HT (1 µM) in the presence of the 5-HT₄-receptor antagonist’s GR 113808 (1 µM) or GR 125487 (1 µM). WT = wild-type mice, 5-HT₄-TG = 5-HT₄-transgenic mice. Data shown are means ± SEM. * p < 0.05 vs. Ctr, ^# p < 0.05 vs. WT.