![header=[] body=[Member] cssheader=[boxoverTooltipHeader] cssbody=[boxoverTooltipBody] delay=[200]](/assets/user-640ae220771289ec897691747ffd93bf.png)
Norepinephrine is implicated in a wide range of physiological processes through activation of nine different G-protein-coupled receptors (alpha1a, alpha1b, alpha1d, alpha2a, alpha2b, alpha2c, beta1, beta2, beta3). The human beta1-adrenergic receptor is a 477–amino acid protein found in various heart and brain tissues. beta1 has an important role in the contractile action of valves in cardiac and digestive systems.