Reese J H, Cooper J R
Biochem Pharmacol. 1984 Oct 1;33(19):3007-11. doi: 10.1016/0006-2952(84)90601-4.
Various agents which are known to affect intracellular levels of cAMP have been assessed for their ability to induce the release of [3H]acetylcholine ([3H]ACH) from a synaptosomal preparation derived from the guinea-pig ileum myenteric plexus. 8-Bromo-cAMP increased the release of [3H]ACh above basal levels. While 8-bromo-cGMP also increased the release, this nucleotide was far less potent than 8-bromo-cAMP. Comparison of the release caused by the cyclic nucleotides to the release induced by the nicotinic agonist dimethylphenylpiperazinium (DMPP) suggested that there is some relationship, as yet undefined, between the 8-bromo-cAMP-induced and the DMPP-induced release, while no relationship was evident between the release induced by 8-bromo-cGMP and that caused by DMPP. The 8-bromo-cAMP-induced release was Ca2+-dependent. Neither adenosine, clonidine, nor oxotremorine (all of which modulate the nicotinically-induced release) affected the 8-bromo-cAMP-induced release. The phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine stimulated the release of [3H]ACh as did the adenylate cyclase activator forskolin. The forskolin-induced release was not affected by adenosine, clonidine or oxotremorine. The ability of the modulators to block the nicotinically-induced release but not the release caused by the cyclic nucleotides indicates that the modulation of release evoked by nicotinic activity does not occur at a step involving protein phosphorylation.
已知多种影响细胞内cAMP水平的物质已被评估其诱导源自豚鼠回肠肌间神经丛的突触体标本释放[3H]乙酰胆碱（[3H]ACh）的能力。8-溴-cAMP使[3H]ACh的释放高于基础水平。虽然8-溴-cGMP也增加了释放，但这种核苷酸的效力远低于8-溴-cAMP。将环核苷酸引起的释放与烟碱激动剂二甲基苯基哌嗪鎓（DMPP）诱导的释放进行比较表明，8-溴-cAMP诱导的释放与DMPP诱导的释放之间存在某种尚未明确的关系，而8-溴-cGMP诱导的释放与DMPP引起的释放之间没有明显关系。8-溴-cAMP诱导的释放是Ca2+依赖性的。腺苷、可乐定和震颤素（所有这些都调节烟碱诱导的释放）均不影响8-溴-cAMP诱导的释放。磷酸二酯酶抑制剂3-异丁基-1-甲基黄嘌呤与腺苷酸环化酶激活剂福斯可林一样刺激[3H]ACh的释放。福斯可林诱导的释放不受腺苷、可乐定或震颤素的影响。调节剂阻断烟碱诱导的释放但不阻断环核苷酸引起的释放的能力表明，烟碱活性引起的释放调节并非发生在涉及蛋白质磷酸化的步骤。
