2026-04-13T07:22:59Zhttps://recercat.cat/oai/request
oai:recercat.cat:2445/1567972025-12-04T21:13:04Zcom_2072_1057col_2072_478781col_2072_478916col_2072_478917col_2072_478929
RECERCAT author Köfalvi, Attila author Moreno Guillén, Estefanía author Cordomí, Arnau author Cai, Ning-Sheng author Fernández Dueñas, Víctor author Ferreira, Samira G. author Guixà-González, Ramón author Sánchez Soto, Marta author Yano, Hideaki author Casadó Anguera, Verònica author Cunha, Rodrigo A. author Sebastião, Ana Maria author Ciruela Alférez, Francisco author Pardo, Leonardo author Casadó, Vicent author Ferré, Sergi 2020-04-22T09:49:58Z2020-04-22T09:49:58Z2020-01-232020-04-22T09:49:58Z Background It has been hypothesized that heteromers of adenosine A2A receptors (A2AR) and cannabinoid CB1 receptors (CB1R) localized in glutamatergic nerve terminals mediate the integration of adenosine and endocannabinoid signaling involved in the modulation of striatal excitatory neurotransmission. Previous studies have demonstrated the existence of A2AR-CB1R heteromers in artificial cell systems. A dependence of A2AR signaling for the Gi protein-mediated CB1R signaling was described as one of its main biochemical characteristics. However, recent studies have questioned the localization of functionally significant A2AR-CB1R heteromers in striatal glutamatergic terminals. Results Using a peptide-interfering approach combined with biophysical and biochemical techniques in mammalian transfected cells and computational modeling, we could establish a tetrameric quaternary structure of the A2AR-CB1R heterotetramer. This quaternary structure was different to the also tetrameric structure of heteromers of A2AR with adenosine A1 receptors or dopamine D2 receptors, with different heteromeric or homomeric interfaces. The specific quaternary structure of the A2A-CB1R, which depended on intermolecular interactions involving the long C-terminus of the A2AR, determined a significant A2AR and Gs protein-mediated constitutive activation of adenylyl cyclase. Using heteromer-interfering peptides in experiments with striatal glutamatergic terminals, we could then demonstrate the presence of functionally significant A2AR-CB1R heteromers with the same biochemical characteristics of those studied in mammalian transfected cells. First, either an A2AR agonist or an A2AR antagonist allosterically counteracted Gi-mediated CB1R agonist-induced inhibition of depolarization-induced glutamate release. Second, co-application of both an A2AR agonist and an antagonist cancelled each other effects. Finally, a CB1R agonist inhibited glutamate release dependent on a constitutive activation of A2AR by a canonical Gs-Gi antagonistic interaction at the adenylyl cyclase level. Conclusions We demonstrate that the well-established cannabinoid-induced inhibition of striatal glutamate release can mostly be explained by a CB1R-mediated counteraction of the A2AR-mediated constitutive activation of adenylyl cyclase in the A2AR-CB1R heteromer. cc-by (c) Köfalvi, Attila et al., 2020 http://creativecommons.org/licenses/by/3.0/es info:eu-repo/semantics/openAccess Proteïnes G Neurociències G Proteins Neurosciences Control of glutamate release by complexes of adenosine and cannabinoid receptors info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion