Beta-1 adrenergic receptor
In 1948, Raymond Ahlquist published a manuscript in the American Journal of Physiology establishing the idea of adrenaline having distinct actions on both alpha and beta receptors.[6][7] GPCRs play a key role in cell signaling pathways and are primarily known for their seven transmembrane (7TM) helices, which have a cylindrical structure and span the membrane.Conversely, TnI phosphorylation results in its facilitated dissociation of calcium from troponin C (TnC) which speeds the muscle relaxation (positive lusitropy).[16] One of the single nucleotide polymorphisms (SNPs) in ADRB-1 is the change from a cytosine to a guanine, resulting in a protein switch from arginine (389R) to glycine (389G) at the 389 codon position.Additionally, patients with heart diseases that have a substitution of glycine for serine at codon 49 (49S > G) show improved cardiac functions and decreased mortality rate.Healthy individuals with a glycine at codon 49 show better cardiovascular functions at rest and response to maximum heart rate during exercise, evident for the cardioprotection related to this polymorphism.[18] Because ADRB-1 play such a critical role in maintaining blood pressure homeostasis and cardiac output, many medications treat these conditions by either potentiating or inhibiting the functions of the ADRB-1.