Mack Cina M, Gordon Christopher J
Neurotoxicology Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA.
J Toxicol Environ Health A. 2007 Mar 1;70(5):439-44. doi: 10.1080/15287390600755299.
Organophosphate (OP) and carbamate (CB) insecticides inhibit cholinesterase (ChE) activity and induce acute hypothermia in adult rats. Studies showed that juveniles are generally more susceptible to neurotoxic insult than adults. However, little is known concerning the effects of OP and CB pesticides on thermoregulation in developing animals. Thus, alterations in core body temperature (Tc) in juvenile animals exposed to an OP and CB insecticide were investigated. Male rat pups were anesthetized on postnatal day (PND) 15 with metofane and a radio transmitter (Data Sciences) was implanted in the abdominal cavity to monitor Tc and motor activity (MA). Two days were allowed for recovery. The PND 17 pups were then dosed by oral gavage with the OP chlorpyrifos (CHP) (1, 5, 10, or 15 mg/kg) or the CB carbaryl (CAR) (10, 20, 80, 120, or 160 mg/kg) or the corn oil vehicle. Pups were returned to their dams and littermates immediately after dosing and monitored for the next several days. CHP doses of 10 and 15 mg/kg resulted in 1.0 degrees C and 2.4 degrees C reductions in Tc, respectively. Tc recovered to control levels by approximately 16 h after dosing. There was significant mortality in rats dosed with 15 mg/kg CHP (6 of 11). CAR doses of 10 to 80 mg/kg had little effect on Tc. The highest dose of CAR (160 mg/kg) resulted in a 1.3 degrees C reduction in Tc that recovered in 9 h. In contrast, past studies found that adult male rats become hypothermic at CHP doses of >25 mg/kg, whereas a CAR dose of 50 mg/kg is effective at inducing hypothermia. Overall, it appears that during the development from preweanling to adult rat, there is a progressive attenuation in CHP-induced hypothermia. Conversely, CAR-induced hypothermia increases as a function of development.
有机磷酸酯（OP）和氨基甲酸酯（CB）类杀虫剂会抑制胆碱酯酶（ChE）的活性，并在成年大鼠中诱发急性体温过低。研究表明，幼体通常比成体对神经毒性损伤更敏感。然而，关于OP和CB农药对发育中动物体温调节的影响，人们所知甚少。因此，研究了暴露于OP和CB杀虫剂的幼年动物核心体温（Tc）的变化。雄性幼鼠在出生后第15天（PND 15）用甲氧氟烷麻醉，并在腹腔内植入无线电发射器（数据科学公司）以监测Tc和运动活动（MA）。给予两天时间恢复。然后在PND 17时，通过口服灌胃给幼鼠施用OP毒死蜱（CHP）（1、5、10或15 mg/kg）或CB西维因（CAR）（10、20、80、120或160 mg/kg）或玉米油载体。给药后立即将幼鼠放回其母鼠和同窝幼鼠身边，并在接下来的几天进行监测。10 mg/kg和15 mg/kg的CHP剂量分别使Tc降低了1.0℃和2.4℃。给药后约16小时，Tc恢复到对照水平。给予15 mg/kg CHP的大鼠有显著死亡率（11只中有6只）。10至80 mg/kg的CAR剂量对Tc影响很小。最高剂量的CAR（160 mg/kg）导致Tc降低1.3℃，并在9小时内恢复。相比之下，过去的研究发现，成年雄性大鼠在CHP剂量>25 mg/kg时会体温过低，而50 mg/kg的CAR剂量可有效诱导体温过低。总体而言，从断奶前幼鼠发育到成年大鼠的过程中，CHP诱导的体温过低似乎逐渐减弱。相反，CAR诱导的体温过低随着发育而增加。
