The pharmacologic effects of β adrenergic agonist drugs, such as orciprenaline, are at least in part attributable to stimulation through β adrenergic receptors of intracellular adenylyl cyclase, the enzyme which catalyzes the conversion of ATP to cAMP. Increased cAMP levels are associated with relaxation of bronchial smooth muscle and inhibition of release of mediators of immediate hypersensitivity from many cells, especially from mast cells.
The pharmacological effects of β-adrenergic agonists like orciprenaline are partly due to their stimulation of intracellular adenylyl cyclase, an enzyme that converts ATP to cAMP. Increased cAMP levels lead to relaxation of bronchial smooth muscle and inhibition of the release of mediators responsible for immediate hypersensitivity from various cells, particularly mast cells.