Fig. 3

Pharmacology of the SAN pacemaker activity during the postnatal development. a–f Percentage inhibition of pacemaking activity by 2 mM Cs⁺, 50 μM Ni²⁺, 10 μM mibefradil, 5 μM E4031, 1 mM 4-AP, and 25 mM TEA in neonatal and adult SAN preparations. Note that the inhibition by Cs⁺ is more marked in neonatal than in adult mice, and that the inhibition of mibefradil is more marked in adult than in neonate mice. Numbers of experiments are indicated in parentheses. Data are mean ± SEM