大鼠无菌性炎症发热时不同脑区cAMP含量和腺苷酸环化酶活性的变化

在大鼠背部皮下注入巴豆油,诱发无菌性炎症(AI)发热,致炎后第一天动物体温上升达高峰,第二天体温开始回降,在第八天体温回降至正常。实验分四组,第一组为对照组,不做致炎处理,第二组为发热高峰组,第三组为发热恢复组,观察大鼠AI发热高峰期及恢复期时不同脑区cAMP含量和腺苷酸环化酶(AC)活性的变化。第四组为发热恢复正常组.观察致炎后第一天至第八天动物体温从高峰障至正常的变化曲线,不做脑组织取材。结果发现:大鼠在发热高峰期与对照组比较,丘脑下部cAMP含量明显增加(P<0.01),并与体温变化呈正相关关系(r=0.893);AC活性显著增强(P<0.001),也与体温变化呈正相关关系(r=0.824),脑皮质、脑干cAMP含量与AC活性均无明显变化。发热恢复组与对照组比较:丘脑下部cAMP含量明显增加(P<0.05),丘脑下部、脑干AC活性均显著增强(P<0.05),而脑皮质cAMP含量和AC活性均无明显变化。作者推论:大鼠AI发热很可能是由于丘脑下部AC活性增强使局部cAMP含量增多所致。

Changes of cyclic AMP and adenylate cyclase activity in different brain areas of rats during aseptic fever

Fourty rats were divided into four groups and the aseptic inflammation was induced by subcutaneous injection of cronton oil into the back of 30 rats. Body temperature were gradually rose up after injection. The highest temperature appeared on the second day, then run down in the following days, and went back to normal on the eighth day. Brain were dissected in 10 normal rats without fever(group 1), other 10 rats at the peak of fever(group 2), and another 10 rats in the recovery phase on the third day (group 3). Ten rats in group 4 were used for observing the whole process of temperature change from injection day to the eighth day without brain dissection. The results showed that at the peak of fever, the levels of both cAMP and AC activities in hypo. thalamus were increased (P<0.01, P<0.001 respectively), compared with control group. Both were positively related to the change of body temperature (r=0.893, r=0.824 respectively). However, there were no obvious changes in the cortex and brainstem. In the recovery phase, the levels of cAMP in hypothalamus, but not in the cortex and brainstem, elevated (P<0.05). The activities of CA in both hypothalamus and brainstem, but not in cortex, increased compared with the control. The author infered that the aseptic fever may be due to the increase production of cAMP which was the result of elevated activity of AC in the hypothalamus.