Summary diagram illustrating signaling pathways involved in β-AR-stimulated cardiac myocyte apoptosis. AR: adrenergic receptors; JNKs: c-Jun-N-terminal kinase; GSK-3β: glycogen synthase kinase-3β; ROS: reactive oxygen species; PKA: protein kinase A; AC: adenylyl cyclase; Gs: stimulatory G protein; Gi: inhibitory G protein; ATP: adenosine triphosphate; cAMP: cyclic adenosine monophosphate; CaMKIIδ: calcium calmodulin kinase IIδ; PI-3K: phosphatidylinositol 3-kinase.