重复给烟碱引起大鼠降温耐受性反应及对活动和体重的影响

Repeated Injection of Nicotine Induced Tolerance to the Hypothermic Response and the Effect on Motor Activity and Body Weight in Rats

目的观察重复给烟碱引起大鼠降温耐受性反应以及对活动和体重的影响。方法用无线遥测技术监测大鼠的体温和活动,观察连续5天重复注射小剂量烟碱(0.5 mg/kg)对SD大鼠体温、活动和体重的影响。结果①第一次给大鼠注射烟碱后可导致大约持续1.5 h的降温反应;但第三次注射烟碱后,雄性和雌性大鼠体温则与对照组相似。②重复给烟碱可以明显降低体重。③每次注射烟碱和生理盐水可引起动物的活动出现短暂的增加反应;从第二次到第五次注射烟碱后雌性大鼠的活动明显多于雄性大鼠。结论重复注射烟碱可导致雄性和雌性大鼠出现降温耐受性反应,但连续注射烟碱后,雌性大鼠的活动明显大于雄性大鼠。另外,重复给烟碱可降低雄性和雌性大鼠的生长速度。

Objective To observe the repeated nicotine exposure lead to tolerance of hypotherrnic effect and the effect on motor activity and body weigh in rats. Methods The effects of daily injections of nicotine at small dosage （0.5 mg/kg） once a day for 5 days on core temperature and motor activity in male and female Sprague-Dawley rats were monitored by radio telemetry. Results （1）The first injection of nicotine in rats led to a hypothermic response for approximately 1.5 hours. But after the third injection of nicotine, changes of core temperature in male and female rats were similar to controls. （2）Repeated treatment with nicotine significantly reduced body weight. （3）Motor activity also increased transiently with each injection of saline and nicotine, but the motor activity response of females was significantly greater than the males for the second through fifth injections of nicotine. Conclusion The results of this study show that repeated injection of nicotine can lead to tolerance of hypothermic response, but motor activity response of females was significantly greater than the male rats after sequential nicotine injections. In addition, repeated nicotine treatment attenuated the growth of male and female rats.