α2-adrenergic receptors include 3 highly homologous subtypes: α2A, α2B, and α2C. These receptors have a critical role in regulating neurotransmitter release from sympathetic nerves and from adrenergic neurons in the central nervous system.
A deletion variant of the α2B adrenergic receptor has been shown to be related to emotional memory in Europeans and Africans.[7] This variant also predisposed people who had it to focus more on negative aspects of a situation.[8] This predisposition remained present in people with the variant gene who took a single dose of the noradrenergic antidepressant reboxetine, but was weakened in people without the variant.[9]
Evolution
The ADRA2B gene (sometimes referenced as A2AB) is used in animals as a nuclear DNA phylogenetic marker.[6] This intronless gene has first been used to explore the phylogeny of the major groups of mammals,[10] and contributed to reveal that placental orders are distributed into four major clades: Xenarthra, Afrotheria, Laurasiatheria, and Euarchontoglires. Comparative analysis of the primary protein sequence of ADRA2B across placentals also showed the high conservation of residues thought to be involved in agonist binding and in G protein–coupling. However, great variations are observed in the very long, third intracellular loop, with a polyglutamyl domain displaying pervasive length differences.[11]
^Todd RM, Müller DJ, Lee DH, Robertson A, Eaton T, Freeman N, Palombo DJ, Levine B, Anderson AK (2013). "Genes for emotion-enhanced remembering are linked to enhanced perceiving". Psychol Sci. 24 (11): 2244–53. doi:10.1177/0956797613492423. PMID24058067. S2CID9603198.
^Madsen O, Scally M, Douady CJ, Kao DJ, DeBry RW, Adkins R, Amrine HM, Stanhope MJ, de Jong WW, Springer MS (Feb 2001). "Parallel adaptive radiations in two major clades of placental mammals". Nature. 409 (6820): 610–4. Bibcode:2001Natur.409..610M. doi:10.1038/35054544. PMID11214318. S2CID4398233.
Weinshank RL, Zgombick JM, Macchi M, Adham N, Lichtblau H, Branchek TA, Hartig PR (Nov 1990). "Cloning, expression, and pharmacological characterization of a human alpha 2B-adrenergic receptor". Molecular Pharmacology. 38 (5): 681–8. PMID2172775.
Chang AC, Ho TF, Chang NC (Oct 1990). "In vitro amplification by polymerase chain reaction of a partial gene encoding the third subtype of alpha-2 adrenergic receptor in humans". Biochemical and Biophysical Research Communications. 172 (2): 817–23. doi:10.1016/0006-291X(90)90748-C. PMID2173582.
Petrash AC, Bylund DB (Jun 1986). "Alpha-2 adrenergic receptor subtypes indicated by [3H]yohimbine binding in human brain". Life Sciences. 38 (23): 2129–37. doi:10.1016/0024-3205(86)90212-2. PMID3012234.
Okusa MD, Huang L, Momose-Hotokezaka A, Huynh LP, Mangrum AJ (Dec 1997). "Regulation of adenylyl cyclase in polarized renal epithelial cells by G protein-coupled receptors". The American Journal of Physiology. 273 (6 Pt 2): F883–91. doi:10.1152/ajprenal.1997.273.6.F883. PMID9435676.
Chotani MA, Mitra S, Su BY, Flavahan S, Eid AH, Clark KR, Montague CR, Paris H, Handy DE, Flavahan NA (Jan 2004). "Regulation of alpha(2)-adrenoceptors in human vascular smooth muscle cells". American Journal of Physiology. Heart and Circulatory Physiology. 286 (1): H59–67. doi:10.1152/ajpheart.00268.2003. PMID12946937.
Cayla C, Heinonen P, Viikari L, Schaak S, Snapir A, Bouloumié A, Karvonen MK, Pesonen U, Scheinin M, Paris H (Feb 2004). "Cloning, characterisation and identification of several polymorphisms in the promoter region of the human alpha2B-adrenergic receptor gene". Biochemical Pharmacology. 67 (3): 469–78. doi:10.1016/j.bcp.2003.09.029. PMID15037199.