Introduction/General Considerations

The adrenergic nervous system (ANS) exerts numerous effects on the cardiovascular system, including increase in cardiac contractility (positive inotropy), heart rate acceleration (positive chronotropy), hastened cardiac relaxation (positive lusitropy), and accelerated atrioventricular conduction (positive dromotropy) Most of these effects are mediated by adrenergic receptors (also known as adrenoceptors, ARs), which belong to the guanine nucleotide-binding G-protein-coupled receptor (GPCR) superfamily [1]. GPCRs are heptahelical transmembrane sensors, accounting for approximately 4% of the entire protein-coding genome, widely considered the most important drug targets in physiology and medicine [2]. These receptors consist of seven membrane-spanning domains, three intra- and three extracellular loops, one extracellular N-terminal domain, and one intracellular C-terminal tail [3].https://nsuworks.nova.edu/hpd_corx_facbooks/1013/thumbnail.jp