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Sci Rep:日本学者揭示动物无需感知外界温度调节体温

摘要 : 2017年7月10日,国际学术权威刊物自然出版集团旗下子刊《Scientific Reports》杂志在线发表了日本名古屋大学Kazuhiro Nakamura研究组的一篇研究论文,论文介绍了行动性体温调节的温度感觉传递机理,研究有助理解人类中暑发病机理。

2017年7月10日,国际学术权威刊物自然出版集团旗下子刊《Scientific Reports》杂志在线发表了日本名古屋大学Kazuhiro Nakamura研究组的一篇研究论文,论文介绍了行动性体温调节的温度感觉传递机理,研究有助理解人类中暑发病机理。

体温调节是动物维持生命最重要的调节功能之一。人类在炎热时出汗带走热量,寒冷时肌肉发抖产生热量。这些反应是自主发生的,与自我意志无关,称为“自律性体温调节”。而动物躲到舒适温度环境、根据温度变化着装、使用空调等是基于意志的行为,称为“行动性体温调节”。这种行动调节体温行为是一种本能行为。

无论哪种体温调节行为都是通过脑的指令。科学家已经了解了自律性体温调节的神经回路,但对行动性体温调节的神经回路尚不甚了解。为进行体温调节,人脑需要接受环境温度信息。环境温度由皮肤的温度感受器感知,其信息通过感觉神经传达给脊髓。

研究人员用两块金属板,在室温25℃下将一块金属板温度设定28℃(中性温度),另一块设置为38℃(酷热)和15℃(寒冷)。在金属板上给大鼠20分钟自由行动时间,大鼠在中性温度的金属板上停留时间最长。这就是躲避酷暑和寒冷,选择舒适的环境温度的体温调节行为。

研究小组发现,与正常大鼠一样,丘脑被破坏的大鼠仍然会选择在中性温度金属板停留。对参与实验的大鼠进行大脑皮层的脑电波测定,在正常大鼠上发现了应对皮肤温度变化的脑电波变化,而在丘脑被破坏的大鼠上没有发现皮肤温度变化引起的脑电波变动。这一结果表明,体温调节行为不需要脊髓丘脑皮层路感知环境温度。

原文链接:

The lateral parabrachial nucleus, but not the thalamus, mediates thermosensory pathways for behavioural thermoregulation

原文摘要:

Thermoregulatory behaviour, such as migration to a comfortable thermal environment, is a representative innate animal behaviour and facilitates effective autonomic regulation of body temperature with a reduced cost of resources. Here we determine the central thermosensory ascending pathway that transmits information on environmental temperature from cutaneous thermoreceptors to elicit thermoregulatory behaviour. To examine the contribution of the spinothalamocortical pathway, which is known to mediate thermosensory transmission for perception of skin temperature, we lesioned thalamic regions mediating this pathway in rats. Thalamic-lesioned rats showed compromised electroencephalographic responses in the primary somatosensory cortex to changes in skin temperature, indicating functional ablation of the spinothalamocortical pathway. However, these lesioned rats subjected to a two-floor innocuous thermal plate preference test displayed intact heat- and cold-avoidance thermoregulatory behaviours. We then examined the involvement of the lateral parabrachial nucleus (LPB), which mediates cutaneous thermosensory signaling to the thermoregulatory center for autonomic thermoregulation. Inactivation of neurons in the LPB eliminated both heat- and cold-avoidance thermoregulatory behaviours and ablated heat defense. These results demonstrate that the LPB, but not the thalamus, mediates the cutaneous thermosensory neural signaling required for behavioural thermoregulation, contributing to understanding of the central circuit that generates thermal comfort and discomfort underlying thermoregulatory behaviours.

来源: Scientific Reports 浏览次数:0

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