热限及热限加致热原负荷时脑脊液及血浆中cAMP含量变化的研究

为探讨内毒素(ET)和内生致热原(EP)热限的机制,在家兔静脉注射非热限与热限剂量的EF或EP后及热限加不同致热原负荷时,用竟争性蛋白结合法检测脑脊液和血浆样品中cAMP的含量。结果发现:(1).脑脊液中cAMP含量随EF性发热效应的增强而升高,到达EP热限后则不再上升,而血浆cAMP含量无类似变化。(2).脑脊液和血浆中cAMP含量均随ET性发热效应的增强而上升,到达ET热限后均不再升高。(3).虽然ET热限的发热水平明显高于EP热限,且EP热限加ET负荷使发热水平超过EP热限;但各组之间脑脊液中cAMP含量却无明显差异。上述结果表明,中枢cAMP生成受限可能既是构成EP热限的重要因素,又是ET热限的一个重要成因。但是除cAMP外,ET热限的构成还与其它因素有关。

Studies on cerebrospinal fluid (c.s.f) and plasma cAMP responses during ET and EP hyperthermic ceiling; hyperthermic ceiling plus pyrogen load

In order to study the mechanisms of ET and EP hyperthermic ceiling the concentration of cAMP in samples of c. s. f. and plasma were measured using the competitive protein binding assay after intraveneous injections of ET and EP in doses of nonhyperthermic ceiling, hyperthermic ceiling and hyperthermic ceiling plus the other pyrogen load. The results showed: (1) The concentration of cAMP in c. s. f. was elevated markdly with increase of fever reaction induced by EP, and was limited when EP hyperthermic ceiling was reached. But there was no analogous change of cAMP in plasma. (2) The contents of cAMP both in c. s. f. and in plasma were apparently correlated simultaneously to fever reaction induced by ET, and were limited when ET hyperthermic ceiling was reached. (3) Although the febrele level of ET hyperthermic ceiling was evidently hegher than that of EP and the altitude of fever exceed EP hyyerthermic ceiling when EP hyperthermic ceiling was added the load of ET. Contents of cAMP in c. s. f. had no significant differences among these groups. The results above indicate that the inhibition of central cAMP synthesis is closely related to the formation of EP hyperthermic ceiling and also is one of an important factors that induce. ET hyperthermic ceiling, which, however, is involved in other mediator except cAMP.