Abstract:ObjectiveTo study the antipyretic effect and the mechanism of Jinyinhua (JYH). MethodsFever models of rabbits were established by intravenous injection of IL-1β. The antipyretic action of JYH was observed. The firing rates of thermosensitive neurons in the POAH were recorded by extracellular microelectrode technology. Results①JYH obviously reduced body temperature of febrile rabbits induced by IL1β(P< 0.01) .②After i.v injection of JYH, the firing rates of warm-sensitive neurons responsed to IL-1β increased from (3.2±1.6) imp/s(before i.v injection of JYH)to (9.7±4.4) imp/s (P<0.01,n=13).In contrast,the firing rates of cold-sensitive neurons decreased from (20.1±5.8) imp/s (before i.v JYH) to (8.4±2.0) imp/s (P<0.01,n=10) .Conclusion①JYH has obvious antipyretic effect on IL1βinduced fever in rabbits.②JYH can reverse the changes of firing rates of thermosensitive neurons treated by IL1β in POAH and plays an antipyetic effect by increase in heat lost and decrease in heat production.
1.2.1 实验动物及体温测量取封闭群健康新西兰兔, 体重1.5~2.5 kg ,基础体温38. 6~39. 2℃,雌雄不限,由广东省医学实验动物中心提供,许可证编号:SCXK(粤) 20030002。实验前将兔置于实验环境中模拟实验操作以适应实验条件2 d ,3~4 h/d,第3天正式实验。实验室温度控制在22~25 ℃。测温时将兔置于特制兔架上,用数字测温仪探头(预先经标准温度计校正) 涂以液体石蜡,插入直肠内10 cm 并固定于尾根部,待体温稳定后每10 min 记录体温1 次,取3 次平均值作为基础体温,实验中每10 min 记录体温1 次。防污措施按发热实验的常规方法进行[1]。
1.2.2 动物分组取健康新西兰兔24只,随机分为4组,分别为生理盐水组(NS):静脉注射NS,1 ml/只;白介素-1β(IL1β)组:静脉注射IL1β,100 ng/只,(用无热原生理盐水稀释成100 ng /ml);金银花和白介素-1β(IL-1β+JYH)组:静脉注射JYH 1 ml/只,30 min后再静脉注射IL-1β(剂量同IL1β组);金银花(JYH)组:静脉注射JYH,1 ml/只。
1.2.3 POAH温度敏感神经元放电的记录取新西兰兔,用25%氨基甲酸乙酯(1.0 g/ kg ,iv) 麻醉,常规消毒,切开气管并作气管插管。
[3] Hori T. An update on themosensitive neurons in the brain :from cellular biology to thermal and nonthermal homeostatic functions (review)[J].Japan J of Physiology ,1991,41 (1) :1.