Epinephrine

Epinephrine, also known as adrenaline, is an endogenous catecholamine that acts as an adrenergic agonist. It activates both α and β adrenergic receptors. For example, activation of α1 receptors on peripheral vascular smooth muscle causes vasoconstriction, increases peripheral resistance, and raises blood pressure. Activation of β1 receptors in the myocardium increases heart rate, myocardial contractility, and cardiac output. Activation of β2 receptors on bronchial smooth muscle causes bronchial smooth muscle relaxation and reduces bronchoconstriction-related responses.