Cunha R A, Johansson B, Fredholm B B, Ribeiro J A, Sebastião A M
Laboratory of Pharmacology, Gulbenkian Institute of Science, Oeiras, Portugal.
Neurosci Lett. 1995 Aug 18;196(1-2):41-4. doi: 10.1016/0304-3940(95)11833-i.
The nature of the adenosine receptors involved in the enhancement of acetylcholine release in the hippocampus was studied. The A2A agonist, CGS 21680, increased the veratridine-evoked release of [3H]acetylcholine from hippocampal synaptosomes. This presynaptic effect of CGS 21680 was greater at 3-30 nM than at 100 nM. The excitatory effect of CGS 21680 was antagonised by the A2 antagonist, DMPX (10 microM), and by the A2A antagonist, CSC (200 nM), but not by the A1 antagonist, DPCPX (20 nM). We also found co-expression of A2A and choline acetyltransferase mRNAs in the nucleus of the diagonal band and the medial septum, where the cholinergic cell bodies that project into the hippocampus are located. These results indicate that A2A adenosine receptors are present in cholinergic nerve terminals in the hippocampus and that activation of these receptors enhances acetylcholine release.
研究了海马体中参与增强乙酰胆碱释放的腺苷受体的性质。A2A激动剂CGS 21680增加了来自海马体突触体的藜芦碱诱发的[3H]乙酰胆碱释放。CGS 21680的这种突触前效应在3 - 30 nM时比在100 nM时更强。CGS 21680的兴奋作用被A2拮抗剂DMPX（10 microM）和A2A拮抗剂CSC（200 nM）拮抗，但不被A1拮抗剂DPCPX（20 nM）拮抗。我们还发现A2A和胆碱乙酰转移酶mRNA在斜角带核和内侧隔中共同表达，投射到海马体中的胆碱能细胞体位于此处。这些结果表明A2A腺苷受体存在于海马体的胆碱能神经末梢中，并且这些受体的激活增强了乙酰胆碱的释放。
