Daniel J W, Oleinick N L
Int J Radiat Biol Relat Stud Phys Chem Med. 1984 Jan;45(1):73-83. doi: 10.1080/09553008414550091.
The levels of cyclic AMP and cyclic GMP have been measured in Physarum plasmodia before and after treatment with gamma-radiation, 2 mM caffeine, or combinations of the two agents and compared to the length of the radiation-induced mitotic delay. Caffeine alone produces a rapid transient elevation of cyclic AMP and a slower delayed elevation of cyclic GMP. Irradiation elicits an immediate transient increase in cyclic AMP and a later cyclic GMP increase which accompanies or precedes the delayed mitosis. A composite pattern is produced by combinations of radiation and caffeine, a distinctive feature of which is an elevated level of cyclic GMP near the time of the radiation-delayed and caffeine-promoted mitosis. With pretreatment by caffeine, the least radiation-induced mitotic delay occurs when plasmodia are irradiated during the caffeine-elicited increase in cyclic GMP. The plasmodium becomes refractory to the reduction of mitotic delay by caffeine at approximately the time it becomes refractory to the further elevation of cyclic GMP by caffeine. The data support a role for cyclic AMP in the onset of and for cyclic GMP in the recovery from mitotic delay induced by ionizing radiation.
在多头绒泡菌原质团接受γ射线、2 mM咖啡因或这两种试剂联合处理之前和之后，已测量了环磷酸腺苷（cAMP）和环磷酸鸟苷（cGMP）的水平，并将其与辐射诱导的有丝分裂延迟的时长进行了比较。单独使用咖啡因会使cAMP迅速短暂升高，使cGMP缓慢延迟升高。辐射会引发cAMP立即短暂增加，随后cGMP增加，这伴随着延迟的有丝分裂或在其之前发生。辐射和咖啡因联合使用会产生一种复合模式，其一个显著特征是在辐射延迟和咖啡因促进的有丝分裂发生时，cGMP水平升高。在咖啡因预处理的情况下，当原质团在咖啡因引起的cGMP增加期间接受辐射时，辐射诱导的有丝分裂延迟最短。原质团在大约对咖啡因进一步升高cGMP变得不敏感的时候，也对咖啡因减少有丝分裂延迟变得不敏感。这些数据支持cAMP在电离辐射诱导的有丝分裂延迟开始时起作用，而cGMP在从这种延迟中恢复时起作用。
