Gs exerts its effects via two pathways. Firstly, it directly opens L-type calcium channels (LTCC) in the plasma membrane. Secondly, it renders adenylate cyclase activated, resulting in an increase of cAMP, activating protein kinase A (PKA) which in turn phosphorylates several targets, such as phospholamban, LTCC, Troponin I (TnI), and potassium channels. Phospholamban phosphorylates deactivates its function which is normally inhibition of SERCA on the sarcoplasmic reticulum (SR) in cardiac myocytes. Due to this, more calcium enters the SR and is therefore available for the next contraction. LTCC phosphorylatation increases its open probability and therefore allows more calcium to enter the myocyte upon cell depolarisation. Both of these mechanisms increase the available calcium for contraction and therefore increase inotropy. Conversely, TnI phosphorylation results in its facilitated dissociation of calcium from troponin C (TnC) which fastens the muscle relaxation (positive lusitropy). Potassium channel phosphorylates increases its open probability which results in shorter refractory period (because the cell repolarises faster), also increasing lusitropy. Furthermore, in nodal cells such as in the SA node, cAMP directly binds to and opens the HCN channels, increasing their open probability, which increases chronotropy.[6]
Gene
Specific polymorphisms in the ADRB1 gene have been shown to affect the resting heart rate and can be involved in heart failure.[1]
Interactions
Beta-1 adrenergic receptor has been shown to interact with DLG4[7] and GIPC1.[8] Interaction between testosterone and β-1 ARs have been shown in anxiolytic behaviors in the basolateral amygdala.[9]
↑Moro C, Tajouri L, Chess-Williams R (January 2013). "Adrenoceptor function and expression in bladder urothelium and lamina propria". Urology. 81 (1): 211.e1–7. doi:10.1016/j.urology.2012.09.011. PMID23200975.
↑American Society of Health-System Pharmacists, Inc. (2005-01-01). "Bisoprolol". MedlinePlus Drug Information. U.S. National Library of Medicine, National Institutes of Health. Archived from the original on 2008-05-20. Retrieved 2008-06-06.
↑Hu LA, Tang Y, Miller WE, Cong M, Lau AG, Lefkowitz RJ, Hall RA (Dec 2000). "beta 1-adrenergic receptor association with PSD-95. Inhibition of receptor internalization and facilitation of beta 1-adrenergic receptor interaction with N-methyl-D-aspartate receptors". The Journal of Biological Chemistry. 275 (49): 38659–66. doi:10.1074/jbc.M005938200. PMID10995758.
↑Hu LA, Chen W, Martin NP, Whalen EJ, Premont RT, Lefkowitz RJ (Jul 2003). "GIPC interacts with the beta1-adrenergic receptor and regulates beta1-adrenergic receptor-mediated ERK activation". The Journal of Biological Chemistry. 278 (28): 26295–301. doi:10.1074/jbc.M212352200. PMID12724327.
↑Mard-Soltani M, Kesmati M, Khajehpour L, Rasekh A, Shamshirgar-Zadeh A (April 2012). "Interaction between Anxiolytic Effects of Testosterone and β-1 Adrenoceptors of Basolateral Amygdala". International Journal of Pharmacology. 8 (5): 344–354. doi:10.3923/ijp.2012.344.354.
Further reading
Frielle T, Kobilka B, Lefkowitz RJ, Caron MG (Jul 1988). "Human beta 1- and beta 2-adrenergic receptors: structurally and functionally related receptors derived from distinct genes". Trends in Neurosciences. 11 (7): 321–4. doi:10.1016/0166-2236(88)90095-1. PMID2465637.
Muszkat M (Aug 2007). "Interethnic differences in drug response: the contribution of genetic variability in beta adrenergic receptor and cytochrome P4502C9". Clinical Pharmacology and Therapeutics. 82 (2): 215–8. doi:10.1038/sj.clpt.6100142. PMID17329986.
Forse RA, Leibel R, Gagner M (Jan 1989). "The effect of Escherichia coli endotoxin on the adrenergic control of lipolysis in the human adipocyte". The Journal of Surgical Research. 46 (1): 41–8. doi:10.1016/0022-4804(89)90180-7. PMID2536864.
Stiles GL, Strasser RH, Lavin TN, Jones LR, Caron MG, Lefkowitz RJ (Jul 1983). "The cardiac beta-adrenergic receptor. Structural similarities of beta 1 and beta 2 receptor subtypes demonstrated by photoaffinity labeling". The Journal of Biological Chemistry. 258 (13): 8443–9. PMID6305985.
Hoehe MR, Otterud B, Hsieh WT, Martinez MM, Stauffer D, Holik J, Berrettini WH, Byerley WF, Gershon ES, Lalouel JM (Jun 1995). "Genetic mapping of adrenergic receptor genes in humans". Journal of Molecular Medicine. 73 (6): 299–306. doi:10.1007/BF00231616. PMID7583452.
Elies R, Ferrari I, Wallukat G, Lebesgue D, Chiale P, Elizari M, Rosenbaum M, Hoebeke J, Levin MJ (Nov 1996). "Structural and functional analysis of the B cell epitopes recognized by anti-receptor autoantibodies in patients with Chagas' disease". Journal of Immunology. 157 (9): 4203–11. PMID8892658.
Oldenhof J, Vickery R, Anafi M, Oak J, Ray A, Schoots O, Pawson T, von Zastrow M, Van Tol HH (Nov 1998). "SH3 binding domains in the dopamine D4 receptor". Biochemistry. 37 (45): 15726–36. doi:10.1021/bi981634+. PMID9843378.
Mason DA, Moore JD, Green SA, Liggett SB (Apr 1999). "A gain-of-function polymorphism in a G-protein coupling domain of the human beta1-adrenergic receptor". The Journal of Biological Chemistry. 274 (18): 12670–4. doi:10.1074/jbc.274.18.12670. PMID10212248.
Podlowski S, Wenzel K, Luther HP, Müller J, Bramlage P, Baumann G, Felix SB, Speer A, Hetzer R, Köpke K, Hoehe MR, Wallukat G (2000). "Beta1-adrenoceptor gene variations: a role in idiopathic dilated cardiomyopathy?". Journal of Molecular Medicine. 78 (2): 87–93. doi:10.1007/s001090000080. PMID10794544.
Shiina T, Kawasaki A, Nagao T, Kurose H (Sep 2000). "Interaction with beta-arrestin determines the difference in internalization behavor between beta1- and beta2-adrenergic receptors". The Journal of Biological Chemistry. 275 (37): 29082–90. doi:10.1074/jbc.M909757199. PMID10862778.
Hu LA, Tang Y, Miller WE, Cong M, Lau AG, Lefkowitz RJ, Hall RA (Dec 2000). "beta 1-adrenergic receptor association with PSD-95. Inhibition of receptor internalization and facilitation of beta 1-adrenergic receptor interaction with N-methyl-D-aspartate receptors". The Journal of Biological Chemistry. 275 (49): 38659–66. doi:10.1074/jbc.M005938200. PMID10995758.
Börjesson M, Magnusson Y, Hjalmarson A, Andersson B (Nov 2000). "A novel polymorphism in the gene coding for the beta(1)-adrenergic receptor associated with survival in patients with heart failure". European Heart Journal. 21 (22): 1853–8. doi:10.1053/euhj.1999.1994. PMID11052857.
Xu J, Paquet M, Lau AG, Wood JD, Ross CA, Hall RA (Nov 2001). "beta 1-adrenergic receptor association with the synaptic scaffolding protein membrane-associated guanylate kinase inverted-2 (MAGI-2). Differential regulation of receptor internalization by MAGI-2 and PSD-95". The Journal of Biological Chemistry. 276 (44): 41310–7. doi:10.1074/jbc.M107480200. PMID11526121.
Hu LA, Chen W, Premont RT, Cong M, Lefkowitz RJ (Jan 2002). "G protein-coupled receptor kinase 5 regulates beta 1-adrenergic receptor association with PSD-95". The Journal of Biological Chemistry. 277 (2): 1607–13. doi:10.1074/jbc.M107297200. PMID11700307.