Orciprenaline is a bronchodilator

Bronchodilator

A bronchodilator is a substance that dilates the bronchi and bronchioles, decreasing resistance in the respiratory airway and increasing airflow to the lungs. Bronchodilators may be endogenous , or they may be medications administered for the treatment of breathing difficulties...

 used in the treatment of asthma

Asthma

Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...

. Orciprenaline is a moderately selective beta₂-adrenergic receptor agonist

Beta2-adrenergic receptor agonist

β2-adrenergic agonists, also known as β2-adrenergic receptor agonists, are a class of drugs used to treat asthma and other pulmonary disease states.-Uses:...

 that stimulates receptors of the smooth muscle in the lungs, uterus, and vasculature supplying skeletal muscle, with minimal or no effect on alpha-adrenergic receptors. The pharmacologic effects of beta adrenergic

Adrenergic

An adrenergic agent is a drug, or other substance, which has effects similar to, or the same as, epinephrine . Thus, it is a kind of sympathomimetic agent...

 agonist

Agonist

An agonist is a chemical that binds to a receptor of a cell and triggers a response by that cell. Agonists often mimic the action of a naturally occurring substance...

drugs, such as orciprenaline, are at least in part attributable to stimulation through beta adrenergic receptors of intracellular adenyl 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.