发热及低体温大鼠下丘脑腺苷酸环化酶和磷酸二酯酶活性的经时变化

Changes of adenyl cyclase and phosphodiesterase activities at different time point in hypothalamus of rats with fever and hypothermia

目的和方法 :采用放射性同位素法观察发热和低体温大鼠下丘脑腺苷酸环化酶 (AC)及磷酸二脂酶(PDE)活性的经时变化。结果 :鲜酵母皮下注射后 4h引起体温明显升高 (P <0 0 1) ,并长时维持在高位水平 ,AC活性在造模后 3h达峰值 (P <0 0 5 ) ,其后活性下降并渐至正常 ,PDE活性在整个过程中略有上升 ;安痛定腹腔注射后15min动物即呈现低体温状态 (P <0 0 1) ,AC活性在 15min时有一短暂上扬后至 4 5min降到最低点 (P <0 0 5 ) ,之后活性逐步回升 ,而PDE活性则在正常水平上下小幅波动。结论 :下丘脑AC活性的增强可能是动物体温升高的重要因素 ,而PDE活性并未相应显著升高则又造成了体温长时的偏高 ;在低体温模型中 ,AC活性的明显下降表明cAMP可能与动物的低温状态有关。

AIM: To observe the changes of adengl cyclase(AC) and phosphodiesterase(PDE) activities of at different time point in hypothalamus of rats with fever and hypothermia. METHODS: Radioisotope method was used to measure the activity of AC and PDE. RESULTS:The fresh yeast caused rats fever after subcutaneous injection 4h( P< 0.01). AC activity reached a peak value at 3rd h after making model ( P< 0.05), and PDE activity increased slightly in the full process of experiment action; Aminopyrine induced rats hypothermia state 15 min after peritoneal injection ( P< 0.01). AC activity was higher than normal animal at 15 th minute after the injection of aminopyrine. But subsequently AC activity decreased rapidly with the lowest value at 45 th minute after the injection ( P< 0.05). PDE activity fluctuated slightly within normal range in the full course of experiment .CONCLUSION: In fever model, it might be important cause of febrile response that AC activity in hypothalamus increased markedly, while PDE might be the factor causing long-term febrile response . In hypothermia model, the obvious decrease in AC activity indicating that cAMP content in hypothalamus might be related to hypothermia status.