Jessen C, Dmi'el R, Choshniak I, Ezra D, Kuhnen G
Physiologisches Institut der Justus-Liebig-Universität Giessen, Aulweg 129, D-35435 Giessen, Germany.
Pflugers Arch. 1998 Oct;436(5):659-66. doi: 10.1007/s004240050686.
The temperatures of the arterial blood and the brain in black Bedouin goats were measured continuously by miniature data loggers. The animals were either euhydrated or dehydrated to 75-80% of the initial body mass by withholding water for 3-4 days during exposure to intense solar radiation. The daily blood temperature means and maxima of were significantly higher in dehydration than in euhydration, but 40 degreesC was rarely exceeded even during the hot hours of the day. Selective brain cooling occurred in euhydration, but its extent was small when blood temperature was below 39.5 degreesC. In dehydration, however, selective brain cooling was frequent and the standard response when blood temperature exceeded 39 degreesC. We believe that selective brain cooling contributes to the inhibition of evaporative heat loss, which is the primary cause of the higher blood temperature in dehydration. Rapid rehydration with cold water induced long-lasting depression of blood temperature. No evidence was found for mechanisms attenuating the subsequent decrease of brain temperature which occurred a few minutes after the uptake of cold water.
通过微型数据记录器连续测量黑色贝都因山羊的动脉血和脑部温度。在强烈太阳辐射下，通过3 - 4天不供水，使动物达到正常水合状态或脱水至初始体重的75 - 80%。脱水时每日平均血温和最高血温显著高于正常水合状态，但即使在一天中炎热时段，也很少超过40℃。正常水合状态下会发生选择性脑冷却，但当血温低于39.5℃时，其程度较小。然而，在脱水状态下，选择性脑冷却频繁发生，且当血温超过39℃时是标准反应。我们认为选择性脑冷却有助于抑制蒸发散热，而蒸发散热是脱水时血温升高的主要原因。用冷水快速补液会导致血温长期降低。未发现有机制可减弱摄入冷水几分钟后脑部温度随后的下降。
