Article date: January 2000
By: Satoko Ohkubo, Junko Kimura, Hironori Nakanishi, Isao Matsuoka, in Volume 129, Issue 2, pages 291-298
We have previously shown that ATP increased cyclic AMP in NG108‐15 cells, which was inhibited by P1 receptor antagonist methylxanthines. In the present study, we examined the effects of P1 and P2 receptor antagonists on cyclic AMP formation induced by β,γ‐methyleneATP (β,γ‐MeATP) and CGS21680, an A2A adenosine receptor agonist, in NG108‐15 cells.
β,γ‐MeATP and CGS21680 increased intracellular cyclic AMP with EC50 values of 8.0±0.98 μM (n=4) and 42±7.5 nM (n=4), respectively.
Several P1 receptor antagonists inhibited both β,γ‐MeATP‐ and CGS21680‐induced cyclic AMP increase with a similar rank order of potency; ZM241385>CGS15943>XAC>DPCPX. However, the pKi values of these antagonists for β,γ‐MeATP were larger than those for CGS21680.
Alloxazine, a P1 receptor antagonist, and several P2 receptor antagonists (PPADS, iPPADS, reactive blue‐2) inhibited β,γ‐MeATP‐induced response, while these antagonists little affected CGS21680‐induced one. Suramin was effective only for β,γ‐MeATP‐induced response at 1 mM.
2‐chloroadenosine (2CADO) and 2‐chloroATP (2ClATP) increased cyclic AMP with similar potencies. The effects of these agonists were both inhibited by ZM241385, but only 2ClATP‐induced response was inhibited by PPADS.
ATP‐ and β,γ‐MeATP‐induced responses were little affected by α,β‐methyleneADP, a 5′‐nucleotidase inhibitor.
These results clearly demonstrate that ATP‐stimulated cyclic AMP formation can be distinguished from the A2A receptor agonist‐induced one by using the several P1 and P2 receptor antagonists.
We have previously shown that ATP increased cyclic AMP in NG108‐15 cells, which was inhibited by P1 receptor antagonist methylxanthines. In the present study, we examined the effects of P1 and P2 receptor antagonists on cyclic AMP formation induced by β,γ‐methyleneATP (β,γ‐MeATP) and CGS21680, an A2A adenosine receptor agonist, in NG108‐15 cells.
β,γ‐MeATP and CGS21680 increased intracellular cyclic AMP with EC50 values of 8.0±0.98 μM (n=4) and 42±7.5 nM (n=4), respectively.
Several P1 receptor antagonists inhibited both β,γ‐MeATP‐ and CGS21680‐induced cyclic AMP increase with a similar rank order of potency; ZM241385>CGS15943>XAC>DPCPX. However, the pKi values of these antagonists for β,γ‐MeATP were larger than those for CGS21680.
Alloxazine, a P1 receptor antagonist, and several P2 receptor antagonists (PPADS, iPPADS, reactive blue‐2) inhibited β,γ‐MeATP‐induced response, while these antagonists little affected CGS21680‐induced one. Suramin was effective only for β,γ‐MeATP‐induced response at 1 mM.
2‐chloroadenosine (2CADO) and 2‐chloroATP (2ClATP) increased cyclic AMP with similar potencies. The effects of these agonists were both inhibited by ZM241385, but only 2ClATP‐induced response was inhibited by PPADS.
ATP‐ and β,γ‐MeATP‐induced responses were little affected by α,β‐methyleneADP, a 5′‐nucleotidase inhibitor.
These results clearly demonstrate that ATP‐stimulated cyclic AMP formation can be distinguished from the A2A receptor agonist‐induced one by using the several P1 and P2 receptor antagonists.
British Journal of Pharmacology (2000) 129, 291–298; doi:10.1038/sj.bjp.0703053
DOI: 10.1038/sj.bjp.0703053
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