ß2 Selective Adrenergic Agonists

• ß₂ selective adrenergic agonists- metaproterenol, terbutaline, albuterol. Activation of pulmonary ß₂ adrenergic receptors result in smooth-muscle relation and bronchodilation.

  • ß₂ receptor-mediated relaxation of vascular smooth muscle may be due to cAMP-dependent kinase phosphorylation of myosin light chain kinase (producing an inactive form)

ß adrenergic receptor agonists also decrease histamine and leukotriene release from lung mast cells.

Alpha₂ Selective Adrenergic Agonists: Clonidine, Guanabenz & Guanfacine

• Alpha₂ selective adrenergic agonists are used to treat essential hypertension.

• Mechanism of action:

  • Activation of central a₂ adrenergic receptors at cardiovascular control centers decreases sympathetic outflow, thus reducing sympathetic vascular tone.

Category: Pharmacology Notes