Constitutive phosphodiesterase activity restricts spontaneous beating rate of cardiac pacemaker cells by suppressing local Ca2+ releases - Vinogradova, T M; Sirenko, S; Lyashkov, A E; Younes, A; Li, Y; Zhu, W; Yang, D; Ruknudin, A M; Spurgeon, H; Lakatta, E G (Circ Res, 2008)