Genetic deletion of the adenosine A2A receptor prevents nicotine-induced upregulation of α7, but not α4β2* nicotinic acetylcholine receptor binding in the brain.
Metaxas, A, Al-Hasani, R, Farshim, P, Tubby, K, Berwick, A, Ledent, C, Hourani, S, Kitchen, I and Bailey, A (2013) Genetic deletion of the adenosine A2A receptor prevents nicotine-induced upregulation of α7, but not α4β2* nicotinic acetylcholine receptor binding in the brain. Neuropharmacology, 71. pp. 228-236.
Metaxas et al 2013.pdf
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Considerable evidence indicates that adenosine A2A receptors (A2ARs) modulate cholinergic neurotransmission, nicotinic acetylcholine receptor (nAChR) function, and nicotine-induced behavioural effects. To explore the interaction between A2A and nAChRs, we examined if the complete genetic deletion of adenosine A2ARs in mice induces compensatory alterations in the binding of different nAChR subtypes, and whether the long-term effects of nicotine on nAChR regulation are altered in the absence of the A2AR gene. Quantitative autoradiography was used to measure cytisine-sensitive [(125)I]epibatidine and [(125)I]α-bungarotoxin binding to α4β2* and α7 nAChRs, respectively, in brain sections of drug-naïve (n = 6) or nicotine treated (n = 5-7), wild-type and adenosine A2AR knockout mice. Saline or nicotine (7.8 mg/kg/day; free-base weight) were administered to male CD1 mice via subcutaneous osmotic minipumps for a period of 14 days. Blood plasma levels of nicotine and cotinine were measured at the end of treatment. There were no compensatory developmental alterations in nAChR subtype distribution or density in drug-naïve A2AR knockout mice. In nicotine treated wild-type mice, both α4β2* and α7 nAChR binding sites were increased compared with saline treated controls. The genetic ablation of adenosine A2ARs prevented nicotine-induced upregulation of α7 nAChRs, without affecting α4β2* receptor upregulation. This selective effect was observed at plasma levels of nicotine that were within the range reported for smokers (10-50 ng ml(-1)). Our data highlight the involvement of adenosine A2ARs in the mechanisms of nicotine-induced α7 nAChR upregulation, and identify A2ARs as novel pharmacological targets for modulating the long-term effects of nicotine on α7 receptors.
|Divisions :||Faculty of Health and Medical Sciences > School of Biosciences and Medicine > Department of Biochemical Sciences|
|Date :||11 April 2013|
|Identification Number :||10.1016/j.neuropharm.2013.03.023|
|Related URLs :|
|Additional Information :||NOTICE: this is the author’s version of a work that was accepted for publication in Neuropharmacology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Neuropharmacology, 71, August 2013, DOI 10.1016/j.neuropharm.2013.03.023.|
|Depositing User :||Symplectic Elements|
|Date Deposited :||11 Sep 2013 08:10|
|Last Modified :||09 Jun 2014 13:48|
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