Adrenergic Receptor Subtypes& G-Protein Coupled Mechanisms a Adrenergic Receptors Phospholipase C activation, IP3 increase through G Mechanism mobilize and increase intracellular free calcium Effects: primarily smooth muscle contraction a Adrenergic Receptors nhibition of adenyl cyclase through Gi proteins Mechanism decrease intracellular cAMP levels Effects: decrease protein phosphorylation, decrease cellular function1 Adrenergic Receptors: Phospholipase C activation, IP3 increase through Gq Mechanism: mobilize and increase intracellular free calcium Effects: primarily smooth muscle contraction 2 Adrenergic Receptors: Inhibition of adenyl cyclase through Gi proteins Mechanism: decrease intracellular cAMP levels Effects: decrease protein phosphorylation, decrease cellular function Adrenergic Receptor Subtypes & G-Protein Coupled Mechanisms 7