Lust A, Fuller A, Maloney S K, Mitchell D, Mitchell G
Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA.
J Exp Biol. 2007 Jul;210(Pt 14):2444-52. doi: 10.1242/jeb.005587.
We have used thermistor/data logger assemblies to measure temperatures in the brain, carotid artery, jugular vein and abdominal cavity, and subcutaneously, in five pronghorn antelope over a summer in Wyoming. Globe and air temperature varied by up to approximately 50 degrees C daily during the summer and maximum solar radiation was approximately 900 W m(-2). Brain temperature (38.9+/-0.3 degrees C) was consistently approximately 0.2-0.5 degrees C higher than carotid blood temperature (38.6+/-0.3 degrees C), which was the same as abdominal temperature (38.8+/-0.4 degrees C). Jugular blood temperature (38.0+/-0.4 degrees C) varied, probably because of changes in Respiratory Evaporative Heat Loss (REHL), and was lower than other temperatures. Subcutaneous temperature (38.3+/-0.6 degrees C) varied, probably because of peripheral vasoactivity, but on average was similar to other temperatures. Carotid blood temperature had a circadian/nycthemeral rhythm weakly but significantly (r=0.634) linked to the time of sunrise, of amplitude 0.8+/-0.1 degrees C. There were daily variations of up to 2.3 degrees C in carotid body temperature in individual animals. An average range of carotid blood temperature of 3.1+/-0.4 degrees C over the study period was recorded for the group, which was significantly wider than the average variation in brain temperature (2.3+/-0.6 degrees C). Minimum carotid temperature (36.4+/-0.8 degrees C) was significantly lower than minimum brain temperature (37.7+/-0.5 degrees C), but maximum brain and carotid temperatures were similar. Brain temperature was kept relatively constant by a combination of warming at low carotid temperatures and cooling at high carotid temperatures and so varied less than carotid temperature. This regulation of brain temperature may be the origin of the amplitude of the average variation in carotid temperature found, and may confer a survival advantage.
我们在怀俄明州的一个夏天，使用热敏电阻/数据记录器组件测量了五只叉角羚大脑、颈动脉、颈静脉、腹腔及皮下的温度。夏季，球温和气温每天变化高达约50摄氏度，最大太阳辐射约为900瓦/平方米。脑温（38.9±0.3摄氏度）始终比颈动脉血温（38.6±0.3摄氏度）高约0.2 - 0.5摄氏度，而颈动脉血温与腹腔温度（38.8±0.4摄氏度）相同。颈静脉血温（38.0±0.4摄氏度）有所变化，可能是由于呼吸蒸发散热（REHL）的改变，且低于其他温度。皮下温度（38.3±0.6摄氏度）也有变化，可能是由于外周血管活性，但平均而言与其他温度相似。颈动脉血温有昼夜节律，与日出时间有微弱但显著的关联（r = 0.634），振幅为0.8±0.1摄氏度。个体动物的颈动脉体温每日变化高达2.3摄氏度。该组在研究期间记录的颈动脉血温平均范围为3.1±0.4摄氏度，显著宽于脑温的平均变化范围（2.3±0.6摄氏度）。颈动脉最低温度（36.4±0.8摄氏度）显著低于脑最低温度（37.7±0.5摄氏度），但脑和颈动脉的最高温度相似。通过在颈动脉低温时升温以及在颈动脉高温时降温的组合，脑温保持相对恒定，因此其变化小于颈动脉温度。脑温的这种调节可能是所发现的颈动脉温度平均变化幅度的起源，并且可能赋予生存优势。
