Kregel K C, Gisolfi C V
Department of Physiology and Biophysics, University of Iowa, Iowa City 52242.
J Appl Physiol (1985). 1989 Mar;66(3):1359-63. doi: 10.1152/jappl.1989.66.3.1359.
Chloraloseanesthetized rats were implanted with Doppler flow probes on the mesenteric, renal, and external caudal arteries and were exposed to an ambient temperature of 40 degrees C. Heart rate, core (Tc) and tail-skin temperatures, and mean arterial blood pressure (MAP) were also monitored. Before heating, the celiac ganglion was removed (ganglionectomy) from one group of animals (n = 11) and a bilateral adrenal demedullation was performed in a second group (n = 14). As Tc progressively increased from 37 degrees C to 43 degrees C, MAP rose to a plateau then fell precipitously as Tc exceeded 41 degrees C. Ganglionectomy eliminated the rise in mesenteric resistance (P less than 0.05) and attenuated the rise in MAP compared with an intact control group (n = 11). Ganglionectomy also increased the heating rate (P less than 0.05) and reduced heat tolerance time (P less than 0.05). Demedullation attenuated the rise in both mesenteric resistance and MAP (P less than 0.05) and increased the rate of heating (P less than 0.05) compared with controls (n = 10). Renal and caudal resistance changes were similar in all groups. These data show the importance of intact adrenal medullas and sympathetic innervation to the splanchnic region in contributing to thermal tolerance in the rat. However, neither factor alone can explain splanchnic vasoconstriction during severe heat stress.
用氯醛糖麻醉大鼠，在其肠系膜动脉、肾动脉和尾外侧动脉植入多普勒血流探头，并使其暴露于40摄氏度的环境温度下。同时监测心率、核心体温（Tc）、尾皮温度和平均动脉血压（MAP）。加热前，对一组动物（n = 11）进行腹腔神经节切除（神经节切除术），对另一组动物（n = 14）进行双侧肾上腺髓质剥除术。随着Tc从37摄氏度逐渐升高至43摄氏度，MAP先升至平台期，然后在Tc超过41摄氏度时急剧下降。与完整对照组（n = 11）相比，神经节切除术消除了肠系膜阻力的升高（P < 0.05），并减弱了MAP的升高。神经节切除术还提高了升温速率（P < 0.05），缩短了耐热时间（P < 0.05）。与对照组（n = 10）相比，肾上腺髓质剥除术减弱了肠系膜阻力和MAP的升高（P < 0.05），并提高了升温速率（P < 0.05）。所有组的肾阻力和尾阻力变化相似。这些数据表明，完整的肾上腺髓质和内脏区域的交感神经支配对大鼠耐热性的贡献具有重要意义。然而，单独任何一个因素都无法解释严重热应激期间的内脏血管收缩。
