Adenosine A1 receptor-mediated inhibition of cyclic AMP accumulation in type-2 but not type-1 rat astrocytes
| Autor: | Marie-Claire Peakman, Stephen J. Hill |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
medicine.medical_specialty
Adenosine Adenosine A2A receptor Adenosine-5'-(N-ethylcarboxamide) Biology Adenylyl cyclase chemistry.chemical_compound Adenosine A1 receptor Internal medicine Cyclic AMP Purinergic P1 Receptor Agonists medicine Animals Cells Cultured CGS-21680 Pharmacology Analysis of Variance Forskolin Dose-Response Relationship Drug Receptors Purinergic P1 Immunohistochemistry Adenosine receptor Rats Endocrinology chemistry Astrocytes Adenosine A2B receptor medicine.drug |
| Zdroj: | European Journal of Pharmacology. 306:281-289 |
| ISSN: | 0014-2999 |
| Popis: | The effects of adenosine receptor-selective ligands on [3H]cyclic AMP accumulation have been investigated in type-1 and type-2 astrocyte-enriched cultures derived from neonatal rat forebrains. In type-1 astrocytes, 5'-N-ethylcarboxamidoadenosine (NECA) caused a concentration-dependent increase in [3H]cyclic AMP accumulation (EC50 = 1.2 microM) which was antagonised by pretreatment with either xanthine amine congener (8-[4-[[[[(2-aminoethyl)amino]carbonyl]methyl]oxy]-phenyl]- 1,3-dipropylxanthine, apparent Kd = 9 nM) or PD115,199 (N-[2-(dimethylamino)ethyl]-N-methyl-4-(1,3-dipropylxanthine) benzene sulphonamide, apparent Kd = 122 nM). In these cultures, N6-cyclopentyladenosine (CPA), did not affect forskolin- or isoprenaline-mediated elevations of [3H]cyclic AMP accumulation. These data indicate that type-1 astrocytes possess adenosine A2B but not adenosine A1 receptors coupled to adenylyl cyclase. In type-2 astrocyte-enriched cultures, 10 microM NECA caused significant elevations of [3H]cyclic AMP accumulation which were similarly inhibited by either 1 microM xanthine amine congener or 10 microM PD115,199 suggesting that they were primarily due to adenosine A2B receptor stimulation. However, CGS 21680 ((2-[[4-(2-carboxyethyl) phenethyl]-amino]adenosine-5'-N-ethylcarboxamide, 10 microM), also significantly increased [3H]cyclic AMP accumulation in type-2 astrocytes suggesting the additional presence of adenosine A2A receptors. Forskolin-mediated elevations of [3H]cyclic AMP accumulation in type-2 astrocytes were inhibited in a concentration-dependent manner by CPA. This effect was reversed by 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, 0.1 microM), confirming the presence of adenosine A1 receptors negatively coupled to adenylyl cyclase in type-2 astrocytes. |
| Databáze: | OpenAIRE |
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