Hitchcock M
J Immunol. 1977 Feb;118(2):578-83.
Cyclic AMP has been implicated in the regulation of the immunologic release of histamine from lung and other tissues and cell types. The mechanism whereby intracellular levels of cAMP are altered during mediator release was investigated. Measurements of histamine, adenylate cyclase, and cAMP phosphodiesterase activities were made in actively and passively sensitized guinea pig lung after challenge with antigen. A transient decrease in basal adenylate cyclase activity occurred which returned to control levels after histamine release. There was no change in cAMP phosphodiesterase activity determined at substrate concentrations of 1 mM and 0.01 mM. The adenylate cyclase response did not occur under the following conditions: 1) incubation of nonsensitized lung with antigen, 2) incubation of sensitized lung with antigen in the absence of extracellular calcium, and 3) incubation of nonsensitized lung with compound 48/80. These observations indicate 1) the adenylate cyclase response and the immunologic release of histamine are intimately related, and 2) the reduction in intracellular levels of cAMP which have been reported to occur during immunologic histamine release are mediated via adenylate cyclase.
环磷酸腺苷（cAMP）与肺及其他组织和细胞类型中组胺的免疫释放调节有关。研究了介质释放过程中细胞内cAMP水平改变的机制。在用抗原攻击后，对主动和被动致敏的豚鼠肺中的组胺、腺苷酸环化酶和cAMP磷酸二酯酶活性进行了测量。基础腺苷酸环化酶活性出现短暂下降，在组胺释放后恢复到对照水平。在底物浓度为1 mM和0.01 mM时测定的cAMP磷酸二酯酶活性没有变化。在以下条件下未出现腺苷酸环化酶反应：1）用抗原孵育未致敏的肺；2）在无细胞外钙的情况下用抗原孵育致敏的肺；3）用化合物48/80孵育未致敏的肺。这些观察结果表明：1）腺苷酸环化酶反应与组胺的免疫释放密切相关；2）据报道在免疫性组胺释放过程中发生的细胞内cAMP水平降低是通过腺苷酸环化酶介导的。
