Periodic arousal from hibernation is necessary for initiation of immune responses in ground squirrels
Periodic arousal from hibernation is necessary for initiation of immune responses in ground squirrels
复制标题
DOI：
10.1152/ajpregu.00562.2001
复制
发表时间：
2002-04-01
影响因子：
2.8
通讯作者：
Nelson, RJ
中科院分区：
文献类型：
--
作者：
Prendergast, BJ;Freeman, DA;Nelson, RJ
金毛黄鼠(Spermophilus Lateralis)经历季节性冬眠，在此期间，核心体温(T-b)值保持在高于环境温度1-2摄氏度。冬眠不是连续的。松鼠的唤醒间隔类似于7天，在此期间，T-b上升到37摄氏度，持续类似16小时；此后，它们返回冬眠，并保持低T(B)S，直到下一次唤醒。在整个冬眠季节，唤醒功能消耗了松鼠冬季能量预算的60%-80%，但它们的功能意义尚不清楚，也存在争议。在冬眠季节，宿主防御机制似乎被下调，并排除了正常的免疫反应。这些实验评估了冬眠和随后的周期性觉醒期间的免疫功能。对细菌脂多糖(LPS)的急性时相反应在冬眠期间停止，在常温唤醒后完全恢复。注射脂多糖(LP)可引起常温动物1-1.5摄氏度的发热，持续8小时。LP对冬眠的松鼠没有影响，既不会引起发热，也不会引起觉醒，但几天后当松鼠下一次从冬眠中唤醒时，确实会出现发热；这种觉醒的持续时间比基准值增加了6倍。侧脑室注射前列腺素E-2可引起冬眠唤醒和诱导发热，提示介导发热反应的神经信号通路在冬眠中起作用。周期性唤醒可以激活休眠的免疫系统，然后免疫系统可以对抗可能在冬眠前或冬眠期间引入的病原体。
Golden-mantled ground squirrels (Spermophilus lateralis) undergo seasonal hibernation during which core body temperature (T-b) values are maintained 1-2degrees C above ambient temperature. Hibernation is not continuous. Squirrels arouse at similar to7-day intervals, during which T-b increases to 37degrees C for similar to16 h; thereafter, they return to hibernation and sustain low T(b)s until the next arousal. Over the course of the hibernation season, arousals consume 60-80% of a squirrel's winter energy budget, but their functional significance is unknown and disputed. Host-defense mechanisms appear to be downregulated during the hibernation season and preclude normal immune responses. These experiments assessed immune function during hibernation and subsequent periodic arousals. The acute-phase response to bacterial lipopolysaccharide (LPS) was arrested during hibernation and fully restored on arousal to normothermia. LPS injection (ip) resulted in a 1-1.5degrees C fever in normothermic animals that was sustained for >8 h. LPS was without effect in hibernating squirrels, neither inducing fever nor provoking arousal, but a fever did develop several days later, when squirrels next aroused from hibernation; the duration of this arousal was increased sixfold above baseline values. Intracerebroventricular infusions of prostaglandin E-2 provoked arousal from hibernation and induced fever, suggesting that neural signaling pathways that mediate febrile responses are functional during hibernation. Periodic arousals may activate a dormant immune system, which can then combat pathogens that may have been introduced immediately before or during hibernation.