Alfa-2 adrenergički receptor

Alfa-2 (α₂) adrenergički receptor (ili adrenoceptor) je G protein-spregnuti receptor koji vezuje G_i heterotrimerni G protein. Postoje tri visoko homologna podtipa, α_2A-, α_2B-, i α_2C- adrenergički receptor. Neke vrste takođe izražavaju četvrti α_2D-adrenergički receptor.^[1] Kateholamini kao što su norepinefrin (noradrenalin) i epinefrin (adrenalin) prenose signal kroz α₂-adrenergički receptor u centralnom i perifernom nervnom sistemu.

Efekti

α₂-adrenergički receptor vezuje oba norepinefrin koga oslobađaju simpatička postgangliona vlakna i epinefrin (adrenalin) koga otpušta adrenalna medula. On vezuje epinefrin sa nešto većim afinitetom. On ima nekoliko opštih funkcija koje su zajedničke sa α₁-adrenergičkim receptorom, a takođe ima i niz specifičnih efekata.

Opšti

Opšti efekti su:

Vazodilatacija arterija^[2]
Vazokonstrikcija arterija ka srcu (koronarnih arterija)^[3], mada ekstent ovog efekta može da bude ograničen^[4]
Vazokonstrikcija vena^[5]
Umanjena motilnost glatkih mišića gastrointestinalnog trakta^[6]

Individualni

Individualna dejstva α₂ receptora su:

Posreduje sinaptičku transmisiju u pre- i postsinaptičkim nervnim terminalima
- Umanjuje otpuštanje acetilholina^[7]
- Umanjuje otpuštanje norepinefrina^[7]
  - Inhibira norepinefrinski sistem u mozgu
Inhibicija^[8] lipolize u adipoznom tkivu^[9]
Indukcija oslobađanja glukagona iz pankreasa
agregacija trombocita
Kontrakcija sfinktera gastrointestinalnog trakta
↓ Sekrecija iz pljuvačnih žlezdi^[10]

Ligandi

Agonisti

Antagonisti

Vidi još

Adrenergički receptor

Reference

^ Ruuskanen JO, Xhaard H, Marjamäki A, Salaneck E, Salminen T, Yan YL, Postlethwait JH, Johnson MS, Larhammar D, Scheinin M (2004). „Identification of duplicated fourth alpha2-adrenergic receptor subtype by cloning and mapping of five receptor genes in zebrafish”. Molecular Biology and Evolution. 21 (1): 14—28. PMID 12949138. doi:10.1093/molbev/msg224.
^ Goodman Gilman, Alfred. Goodman & Gilman's The Pharmacological Basis of Therapeutics. Tenth Edition. McGraw-Hill (2001): Page 140.
^ Woodman OL, Vatner SF (1987). „Coronary vasoconstriction mediated by α₁- and α₂-adrenoceptors in conscious dogs”. Am. J. Physiol. 253 (2 Pt 2): H388—93. PMID 2887122. Архивирано из оригинала 17. 05. 2010. г. Приступљено 11. 02. 2011.
^ Sun D, Huang A, Mital S, Kichuk MR, Marboe CC, Addonizio LJ, Michler RE, Koller A, Hintze TH, Kaley G (2002). „Norepinephrine elicits beta2-receptor-mediated dilation of isolated human coronary arterioles”. Circulation. 106 (5): 550—5. PMID 12147535. ^{[мртва веза]}
^ Elliott J (1997). „Alpha-adrenoceptors in equine digital veins: evidence for the presence of both α₁ and α₂-receptors mediating vasoconstriction”. J. Vet. Pharmacol. Ther. 20 (4): 308—17. PMID 9280371. doi:10.1046/j.1365-2885.1997.00078.x.
^ Sagrada A, Fargeas MJ, Bueno L (1987). „Involvement of α₁ and α₂ adrenoceptors in the postlaparotomy intestinal motor disturbances in the rat”. Gut. 28 (8): 955—9. PMC 1433140 . PMID 2889649. doi:10.1136/gut.28.8.955.
^ ^а ^б Rang, H. P. (2003). Pharmacology. Edinburgh: Churchill Livingstone. стр. 163. ISBN 978-0-443-07145-4.
^ Wright EE, Simpson ER (1981). „Inhibition of the lipolytic action of beta-adrenergic agonists in human adipocytes by alpha-adrenergic agonists”. J. Lipid Res. 22 (8): 1265—70. PMID 6119348. Архивирано из оригинала 23. 03. 2009. г. Приступљено 11. 02. 2011.
^ Fitzpatrick, David; Purves, Dale; Augustine, George (2004). „Table 20:2”. Neuroscience (Third изд.). Sunderland, Mass: Sinauer. ISBN 978-0-87893-725-7.
^ Khan ZP, Ferguson CN, Jones RM (1999). „alpha-2 and imidazoline receptor agonists. Their pharmacology and therapeutic role”. Anaesthesia. 54 (2): 146—65. PMID 10215710. doi:10.1046/j.1365-2044.1999.00659.x.
^ ^а ^б Haenisch B, Walstab J, Herberhold S, Bootz F, Tschaikin M, Ramseger R, Bönisch H (2010). „Alpha-adrenoceptor agonistic activity of oxymetazoline and xylometazoline”. Fundam Clin Pharmacol. 24 (6): 729—39. PMID 20030735. doi:10.1111/j.1472-8206.2009.00805.x.

Literatura

Fitzpatrick, David; Purves, Dale; Augustine, George (2004). „Table 20:2”. Neuroscience (Third изд.). Sunderland, Mass: Sinauer. ISBN 978-0-87893-725-7.
Rang, H. P. (2003). Pharmacology. Edinburgh: Churchill Livingstone. стр. 163. ISBN 978-0-443-07145-4.

Spoljašnje veze

„Adrenoceptors”. IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology. Архивирано из оригинала 12. 01. 2015. г.

[pmid12949138-1] Ruuskanen JO, Xhaard H, Marjamäki A, Salaneck E, Salminen T, Yan YL, Postlethwait JH, Johnson MS, Larhammar D, Scheinin M (2004). „Identification of duplicated fourth alpha2-adrenergic receptor subtype by cloning and mapping of five receptor genes in zebrafish”. Molecular Biology and Evolution. 21 (1): 14—28. PMID 12949138. doi:10.1093/molbev/msg224.

[2] Goodman Gilman, Alfred. Goodman & Gilman's The Pharmacological Basis of Therapeutics. Tenth Edition. McGraw-Hill (2001): Page 140.

[pmid2887122-3] Woodman OL, Vatner SF (1987). „Coronary vasoconstriction mediated by α₁- and α₂-adrenoceptors in conscious dogs”. Am. J. Physiol. 253 (2 Pt 2): H388—93. PMID 2887122. Архивирано из оригинала 17. 05. 2010. г. Приступљено 11. 02. 2011.

[pmid12147535-4] Sun D, Huang A, Mital S, Kichuk MR, Marboe CC, Addonizio LJ, Michler RE, Koller A, Hintze TH, Kaley G (2002). „Norepinephrine elicits beta2-receptor-mediated dilation of isolated human coronary arterioles”. Circulation. 106 (5): 550—5. PMID 12147535. ^{[мртва веза]}

[pmid9280371-5] Elliott J (1997). „Alpha-adrenoceptors in equine digital veins: evidence for the presence of both α₁ and α₂-receptors mediating vasoconstriction”. J. Vet. Pharmacol. Ther. 20 (4): 308—17. PMID 9280371. doi:10.1046/j.1365-2885.1997.00078.x.

[pmid2889649-6] Sagrada A, Fargeas MJ, Bueno L (1987). „Involvement of α₁ and α₂ adrenoceptors in the postlaparotomy intestinal motor disturbances in the rat”. Gut. 28 (8): 955—9. PMC 1433140 . PMID 2889649. doi:10.1136/gut.28.8.955.

[Rang163-7] а ^б Rang, H. P. (2003). Pharmacology. Edinburgh: Churchill Livingstone. стр. 163. ISBN 978-0-443-07145-4.

[pmid6119348-8] Wright EE, Simpson ER (1981). „Inhibition of the lipolytic action of beta-adrenergic agonists in human adipocytes by alpha-adrenergic agonists”. J. Lipid Res. 22 (8): 1265—70. PMID 6119348. Архивирано из оригинала 23. 03. 2009. г. Приступљено 11. 02. 2011.

[purves-9] Fitzpatrick, David; Purves, Dale; Augustine, George (2004). „Table 20:2”. Neuroscience (Third изд.). Sunderland, Mass: Sinauer. ISBN 978-0-87893-725-7.

[pmid10215710-10] Khan ZP, Ferguson CN, Jones RM (1999). „alpha-2 and imidazoline receptor agonists. Their pharmacology and therapeutic role”. Anaesthesia. 54 (2): 146—65. PMID 10215710. doi:10.1046/j.1365-2044.1999.00659.x.

[xyloOxy-11] а ^б Haenisch B, Walstab J, Herberhold S, Bootz F, Tschaikin M, Ramseger R, Bönisch H (2010). „Alpha-adrenoceptor agonistic activity of oxymetazoline and xylometazoline”. Fundam Clin Pharmacol. 24 (6): 729—39. PMID 20030735. doi:10.1111/j.1472-8206.2009.00805.x.

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