Maskrey M
Department of Physiology, School of Medicine, University of Auckland, New Zealand.
Am J Physiol. 1990 Sep;259(3 Pt 2):R492-8. doi: 10.1152/ajpregu.1990.259.3.R492.
During surgery under pentobarbital sodium anesthesia, 20 rats had heat exchange devices implanted into their abdominal cavity. After recovery, 14 rats underwent two sets of trials, one in which body core temperature (Tbc) was lowered to 34.5-35.5 degrees C and another in which Tbc was raised to 40.5-41.5 degrees C. Rats breathed air and hypoxic (15, 11, and 7% O2 in N2) and hypercapnic (2, 4, and 6% CO2 in air) gas mixtures. Respiratory responses were measured using a barometric method and compared with data from the same rats breathing the gas mixtures at normal Tbc (37.5-38.5 degrees C) before surgery. The six remaining rats served as controls (Tbc unchanged). Lowering Tbc increased respiration in air, whereas heating had no effect. Hypothermia and severe hypoxia combined to inhibit respiration when compared with breathing air at lowered Tbc or low O2 at normal Tbc. The CO2 response slope became steeper when Tbc was raised, suggesting an increased CO2 sensitivity. Possible sites for the hypothermia-hypoxia interaction and the hyperthermia-hypercapnia interaction are discussed.
在戊巴比妥钠麻醉下进行手术时，将20只大鼠的热交换装置植入腹腔。恢复后，14只大鼠进行了两组试验，一组将体核温度（Tbc）降至34.5 - 35.5摄氏度，另一组将Tbc升至40.5 - 41.5摄氏度。大鼠呼吸空气以及低氧（氮气中氧气含量为15%、11%和7%）和高碳酸（空气中二氧化碳含量为2%、4%和6%）混合气体。使用气压法测量呼吸反应，并与手术前相同大鼠在正常Tbc（37.5 - 38.5摄氏度）下呼吸混合气体的数据进行比较。其余6只大鼠作为对照（Tbc不变）。降低Tbc会增加在空气中的呼吸频率，而加热则没有影响。与在降低的Tbc下呼吸空气或在正常Tbc下呼吸低氧气体相比，体温过低和严重低氧共同抑制呼吸。当Tbc升高时，二氧化碳反应斜率变得更陡，表明二氧化碳敏感性增加。讨论了体温过低 - 低氧相互作用和体温过高 - 高碳酸相互作用的可能部位。
