Effects of Environmental Temperature on Cardio-Vascular System in Experimental Animals

为探讨环境温度对实验动物心钠素的影响，用生物遥测系统测定了热(33℃)和冷(L5℃)环境下仓鼠、豚鼠和兔的血压、心率和体温。进一步，用免疫组织化学、电子显微镜和放射免疫分析法检测了两种环境条件下动物耳廓心肌细胞和血浆中ANP的水平。(1)平均动脉压(BP)、心率(HR)、平均动脉压(BT)：冷条件下各物种的HR、BP、BT无明显变化，但热条件下豚鼠的血压明显低于正常环境条件下(22℃)。在高温条件下，所有物种的心率没有变化，但在高温条件下，所有动物的BT显著高于对照水平。(2)血浆ANP浓度：热状态下豚鼠血浆ANP浓度显著低于正常状态，而金黄地鼠和兔热状态下血浆ANP浓度无明显变化。在寒冷条件下，所有物种中的浓度都没有显著变化。(3)免疫组织化学及超微结构：热状态下24小时豚鼠耳廓心肌细胞ANP免疫反应(IR)弱于正常状态，超微结构中ANP颗粒数量较正常状态少。热状态下金黄地鼠和兔心肌细胞的IR和ANP颗粒数与正常状态相同。在低温条件下，各物种心肌细胞的IR和ANP颗粒数均无明显变化。本研究提示炎热环境对豚鼠循环心钠素和心血管系统有较大影响。

To elucidate effects of environmental temperature on atrial natriuretic peptide (ANP) in experimental animals, the blood pressure (BP), heart rate (HR) and body temperature (BT) in hamsters, Guinea pigs, and rabbits under hot (33℃) and cold (l5℃) environmental conditions were measured by a biotelemetric system. Further, the ANP levels of auricular cardiocytes and plasma were examined by immunohistochemistry, electron microscopy, and radioimmunoassay in those animals under both environmental conditions. (1) Mean arterial BP, HR, BT : there was no change of HR, BP and BT in all species under cold condition, but BP of Guinea pig was significantly decreased in hot condition compared to the normal environmental condition (22℃). There was no change of HR in all species under hot condition, but BT in all animals was significantly increased under hot condition compared to the control level. (2) Plasma ANP concentration: the concentration of Guinea pig in hot condition was significantly lower than that in normal condition, but there was no change in the concentration of hamster and rabbit under hot condition. The concentration in all species under cold condition did not significantly change. (3) Immunohistochemistry and ultrastructure : ANP immunoreactivity (IR) in the auricular cardiocytes of Guinea pig after 24 hours under hot condition was weaker than that in normal condition, and ultrastructurally, the number of ANP-granules in the cardiocytes of' Guinea pig under hot condition was fewer than that in normal condition. The IR and the number of ANP-granules in the cardiocytes of hamster and rabbit under hot condition were the same level as normal condition. In cold condition, there were no changes in the IR and the number of ANP-granules of the cardiocytes in all species. The present study suggests that the circulating ANP and cardio-vascular systems in Guinea pig are greatly influenced by hot environmental condition.