Gordon C J, Yang Y, Ramsdell J S
Neurotoxicology Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA.
Toxicon. 1998 Oct;36(10):1341-7. doi: 10.1016/s0041-0101(98)00010-5.
Many types of marine algal toxins induce marked hypothermic responses in mice. However, it is not known if the thermoregulatory response to these toxins results from dysfunction in the control of core temperature (Tc) or is a coordinated response to lower Tc as occurs with a variety of xenobiotic insults. Female CD-1 mice were administered purified maitotoxin (338 ng/kg; IP) and placed in a temperature gradient for 5 h that permitted the selection of ambient temperatures (Ta) ranging between 15 and 37 degrees C. Tc was monitored simultaneously by radiotelemetric probes that were surgically implanted into the abdominal cavity at least one week before maitotoxin injection. Maitotoxin led to a rapid reduction in Tc from 37 to 34 degrees C within 30 min after injection. There was a simultaneous 4 degrees C reduction in Ta selected by mice within 15 min after injection. Selected Ta recovered rapidly, increased above baseline for approximately one hour, then remained near baseline levels for the remainder of the test period in the gradient. Tc remained approximately 1 to 2 degrees C below control levels throughout the test period. In the temperature gradient, mice can select Ta's warm enough to offset the hypothermic effects of maitotoxin. That cooler Ta's are selected initially after maitotoxin injection suggest that the central neural control of body temperature is affected by the toxin. We postulate that the hypothermic response may represent an adaptive response to enhance survival following exposure to polyether toxins.
许多种类的海洋藻毒素可在小鼠中诱发明显的体温过低反应。然而，尚不清楚对这些毒素的体温调节反应是源于核心体温（Tc）控制功能障碍，还是像多种外源化学物损伤时那样，是对降低的Tc的一种协调反应。给雌性CD-1小鼠腹腔注射纯化的刺尾鱼毒素（338 ng/kg），并将其置于温度梯度环境中5小时，该环境允许小鼠选择15至37摄氏度之间的环境温度（Ta）。在注射刺尾鱼毒素至少一周前，通过手术将无线电遥测探头植入腹腔，同时监测Tc。注射刺尾鱼毒素后30分钟内，Tc迅速从37摄氏度降至34摄氏度。注射后15分钟内，小鼠选择的Ta同时降低了4摄氏度。选择的Ta迅速恢复，在约一小时内升至基线以上，然后在梯度试验的剩余时间内保持在接近基线水平。在整个试验期间，Tc始终比对照水平低约1至2摄氏度。在温度梯度环境中，小鼠可以选择足够温暖的Ta来抵消刺尾鱼毒素的体温过低效应。刺尾鱼毒素注射后最初选择较低的Ta，这表明毒素影响了体温的中枢神经控制。我们推测，体温过低反应可能代表一种适应性反应，以提高暴露于聚醚毒素后的存活率。
