 relaxing smooth muscle), or inhibitory (i.e.inhibiting adenyl cyclase (AC) production of cyclic AMP [cAMP]); e) G proteins types to which they link and activate, i.e.those containing the Gs alpha subunit, Gi alpha subunit, Gq alpha subunit and/or G12 subunit; and f) signaling pathways which they regulate including Adenyl cyclase which when activated increases cellular cAMP and when inhibited reduces the cellular levels of this secondary messenger; Phosphoinositide 3-kinase which when activated is responsible for forming phosphatidylinositol 3-phosphate, phosphatidylinositol (3,4)-bisphosphate, and phosphatidylinositol (3,4,5)-trisphosphate secondary messengers; Phospholipase C (PLC) which when activated is responsible for forming Inositol trisphosphate (IP3) and diacylglycerol secondary messengers that are, respectively, responsible for raising the levels of Ca2+ in the cellular cytosol to control the activity of Ca2+-cell signaling agents and for activating protein kinase C (PKC) secondary messengers; and Extracellular signal-regulated kinases (ERK), p38 mitogen-activated protein kinases (p38 Mpk), and cAMP response element-binding protein (CREB) which when activated phosphorylate and thereby influence the activity of key proteins that govern cell function.