家兔EGTA性发热时脑腹中隔区AVP含量的变化

Change of AVP content in the ventral septal area of rabbit brain in EGTA-induced fever

本研究采用新西兰家兔４８只，随机分成４组，分别观察向侧脑室灌注ＥＧＴＡ、ＥＧＴＡ＋ＣａＣｌ＿２或ＣａＣｌ＿２对体温和脑腹中隔区ＡＶＰ含量的影响。结果表明，侧脑室灌注ＥＧＴＡ，不仅引起结肠温度明显上升（Ｐ＜０．００１）．还引起腹中隔区ＡＶＰ含量明显降低（Ｐ＜０．０５）；灌注ＥＧＴＡ后立即灌注ＣａＣｌ＿２，抑制了结肠温度的升高并逆转了腹中隔ＡＶＰ含量的降低。体温反应指数与腹中隔区ＡＶＰ含量呈显著负相关（ｒ＝－０．８３７４，Ｐ＜０．０１）；单独灌注ＣａＣｌ＿２引起结肠温度下降和腹中隔ＡＶＰ含量明显增加（Ｐ＜０．０１），提示ＡＴＰ可能参与ＥＧＴＡ性发热的中枢调节机制，中枢Ｃａ￣（２＋）浓度或Ｎａ￣＋／Ｃａ￣（２＋）比值变化可能是调控发热时腹中隔区ＡＶＰ释放的一个重要因素。

The present study observed the change of AVP content in the ventral sep-tal area(VSA)induced by infusion of EGTA,EGTA + CaCl_2 or CaCl_2 into the lateralcerebral ventricle of rabbit,respectively.Forty-eight New Zealand white rabbits of bothsexse were used in the experiment.The colonic temperature was measured using a ther-mistor probe inserted 10em beyond the anus and recorded at 10 minute intervals.At 90minute after infusion,all animals were decapitated.The brain tissue of the VSA wasextracted and determined for the content of a rginine vasopressin(AVP)by radioimmu-noassay.The results showed that infusion of EGTA evoked a rise in colonic temperature(P<0.00 1),while the content of AVP was decreased(P<0.05).Infusing CaCl_2 into thelateral cerebral ventricle suppressed thoroughly EGTA-induced fever and reversed thedecrease of AVP content in the VSA induced by infusion of EGTA.It appeared to be asignificant negatiye correlation between the content of AVP and 1.5 h thermal responseindex(TRI 1.5).In addition,infusion of CaCl_2 into the lateral cerebral ventricle resultedin a great drop in colonic temperature and increase in the content of AVP in the VSA.Above results indicate that AVP in the VSA of rabbit brain may play a role in thecentral regulation mechanism of EGTA-induced fever,and the change of Ca￣[2+] concentra- tion in the central nervous system may be an important factor in the regulation ofAVP release in the VSA.