Fig. 1.
Cardiomyocyte cellular mechanisms of action of positive inotropic agents. (I): the β-adrenergic agonists (dobutamine and main catecholamines); (II): the cardiac glycosides (digoxin); (III): the type III phosphodiesterase inhibitors (milrinone); (IV): the calcium sensitizing agents (levosimendan). AC = adenylate cyclase; ATP = adenosine triphosphate; cAMP = cyclic adenosine monophosphate; G1 = stimulating G protein; G2 = inhibitory G protein; PKA = protein kinase A; SERCA = sarcoplasmic reticulum calcium pump. Modified, with permission, from Fourati M, Methamen M, Mebazaa A: Choix pratique et raisonné d’un agent inotrope positif en chirurgie cardiaque. Anesthésie-réanimation en chirurgie cardiaque: Nouveaux concepts et perspectives. Edited by Fellahi JL. Paris, Arnette, 2006, pp 181–90.