Baker M A, Chapman L W
Science. 1977 Feb 25;195(4280):781-3. doi: 10.1126/science.836587.
In alert, resting dogs, the brain is warmer than arterial blood in the common carotid artery. When dogs run, brain temperature drops, despite a sharp rise in carotid blood temperature, and is maintained 1.3 degrees C below carotid temperature during exercise. This brain cooling apparently results from countercurrent heat exchange between warm arterial blood supplying the brain and cool venous blood draining the nose and mouth. The heat exchange occurs in the arteries at the base of the brain, which form a rudimentary carotid rete in the dog, and is greatest during exercise, when respiratory evaporation is at a peak. In animals with a carotid rete, the brain is protected against overheating during the severe thermal stress of exercise.
在警觉、休息状态下的狗，其大脑比颈总动脉中的动脉血温度更高。当狗奔跑时，尽管颈动脉血液温度急剧上升，但大脑温度却会下降，并且在运动过程中大脑温度维持在比颈动脉温度低1.3摄氏度。这种大脑降温显然是由于供应大脑的温热动脉血与从鼻子和嘴巴流出的凉爽静脉血之间的逆流热交换所致。热交换发生在脑底部的动脉中，这些动脉在狗体内形成了一个原始的颈动脉网，并且在运动期间（此时呼吸蒸发达到峰值）热交换最为显著。在具有颈动脉网的动物中，在运动的严重热应激期间，大脑能够防止过热。
