Interactions among adenosine deaminase, adenosine A1 receptors and dopamine D1 receptors in stably cotransfected fibroblast cells and neurons
| Autor: | Kjell Fuxe, Silvia Ginés, Francisco Ciruela, Serena Latini, Sergi Ferré, Joëlle Hillion, Meritxell Canals, Rafael Franco, Francesca Bordoni, Felicita Pedata, L. F. Agnati, W Staines, Carmen Lluis, Maria Torvinen |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Adenosine
Adenosine Deaminase Transfection Cell Line Mice Adenosine A1 receptor Adenosine deaminase Purinergic P1 Receptor Agonists medicine Animals Humans Receptor Cerebral Cortex Neurons Microscopy Confocal biology Chemistry Receptors Dopamine D1 General Neuroscience Receptors Purinergic P1 Fibroblasts Purinergic signalling Adenosine A3 receptor Immunohistochemistry Molecular biology biology.protein 2 3 4 5-Tetrahydro-7 8-dihydroxy-1-phenyl-1H-3-benzazepine Adenosine Deaminase Inhibitor Adenosine A2B receptor medicine.drug |
| Zdroj: | Neuroscience. 113:709-719 |
| ISSN: | 0306-4522 |
| Popis: | The role of adenosine deaminase in the interactions between adenosine A(1) and dopamine D(1) receptors was studied in a mouse fibroblast cell line stably cotransfected with human D(1) receptor and A(1) receptor cDNAs (A(1)D(1) cells). Confocal laser microscopy analysis showed a high degree of adenosine deaminase immunoreactivity on the membrane of the A(1)D(1) cells but not of the D(1) cells (only cotransfected with human D(1) receptor cDNAs). In double immunolabelling experiments in A(1)D(1) cells and cortical neurons a marked overlap in the distribution of the A(1) receptor and adenosine deaminase immunoreactivities and of the D(1) receptor and adenosine deaminase immunoreactivities was found. Quantitative analysis of A(1)D(1) cells showed that adenosine deaminase immunoreactivity to a large extent colocalizes with A(1) and D(1) receptor immunoreactivity, respectively. The A(1) receptor agonist caused in A(1)D(1) cells and in cortical neurons coaggregation of A(1) receptors and adenosine deaminase, and of D(1) receptors and adenosine deaminase. The A(1) receptor agonist-induced aggregation was blocked by R-deoxycoformycin, an irreversible adenosine deaminase inhibitor. The competitive binding experiments with the D(1) receptor antagonist [(3)H]SCH-23390 showed that the D(1) receptors had a better fit for two binding sites for dopamine, and treatment with the A(1) receptor agonist produced a disappearance of the high-affinity site for dopamine at the D(1) receptor. R-Deoxycoformycin treatment, which has previously been shown to block the interaction between adenosine deaminase and A(1) receptors, and which is crucial for the high-affinity state of the A(1) receptor, also blocked the A(1) receptor agonist-induced loss of high-affinity D(1) receptor binding. The conclusion of the present studies is that the high-affinity state of the A(1) receptor is essential for the A(1) receptor-mediated antagonistic modulation of D(1) receptors and for the A(1) receptor-induced coaggregates of A(1) and adenosine deaminase, and of D(1) and adenosine deaminase. Thus, the confocal experiments indicate that both A(1) and D(1) receptors form agonist-regulated clusters with adenosine deaminase, where the presence of a structurally intact adenosine deaminase bound to A(1) receptors is important for the A(1)-D(1) receptor-receptor interaction at the level of the D(1) receptor recognition. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect