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（ANP）的影响，用生物遥测系统测定了热（33℃）和冷（15 ℃）环境条件下仓鼠、豚鼠和家兔的血压（BP）、心率（HR）和体温（BT）。此外，在这两种环境条件下，这些动物的心房心肌细胞和血浆心钠素水平进行了检查，免疫组织化学，电子显微镜，放射免疫分析。(1)平均动脉血压、心率、体温：在寒冷条件下，所有物种的心率、血压和体温均无变化，但与正常环境条件（22℃）相比，豚鼠在炎热条件下的血压显著降低。在高温条件下，所有动物的HR均无变化，但与对照组相比，所有动物的BT均显著增加。(2)血浆ANP浓度：热环境下豚鼠血药浓度明显低于常温下，而金黄地鼠和家兔血药浓度无明显变化。在寒冷条件下，所有物种的浓度没有显着变化。(3)免疫组化和超微结构：热应激24小时后豚鼠心房心钠素免疫反应（IR）较正常时减弱，超微结构上热应激豚鼠心房心钠素颗粒数量较正常时减少。热环境下仓鼠和家兔心肌细胞的IR和ANP颗粒数与正常情况相同。在低温条件下，所有动物的心肌细胞的IR和ANP颗粒的数量没有变化。提示热环境对豚鼠循环心钠素及心血管系统有明显影响。

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.