Pharmacology of Adrenaline, Noradrenaline, and Their Receptors

Adrenaline and noradrenaline are important catecholamines of the biological system, responsible for the regulation of major functions of the body via their action on the brain. This noradrenaline is the chief neurotransmitter of the sympathetic nervous system, whereas adrenaline is an important metabolic hormone, known to play a vital role in the cardiovascular system and a mediator of the fight-or-flight response. These catecholamines act in the system through the membrane-bound GPCRs, adrenergic receptors (ARs). Two major classes of ARs, a-ARs and Β-ARs, facilitate a number of functions at central and peripheral sites. There are two subtypes of a-ARs (a1-AR and a2-AR), whereas three different subtypes of Β-ARs have been identified-Β1-AR, Β2-AR, and Β3-AR. Based on their role, different AR modulators have been introduced clinically for their therapeutic application. In this chapter, we focus on the pharmacology of the two catecholamines through their action on different ARs within the biosystem and the modulators of ARs towards the treatment of potentially life-threatening conditions.