Central efferent pathways for cold-defensive and febrile shivering
Central efferent pathways for cold-defensive and febrile shivering
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DOI：
10.1113/jphysiol.2011.210047
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发表时间：
2011-07-15
影响因子：
5.5
通讯作者：
Morrison, Shaun F.
中科院分区：
文献类型：
--
作者：
Nakamura, Kazuhiro;Morrison, Shaun F.
寒战是一种由脑机制控制的显著的躯体运动性产热反应。我们记录了麻醉大鼠的肌电图，以阐明颤抖的中枢神经回路，并确定了几个脑区的温度调节神经元包括驱动皮肤冷却和热原刺激颤抖反应的传出通路。我们同时监测交感神经效应器的参数：棕色脂肪组织（BAT）温度为非颤抖性产热和动脉压和心血管反应的心率。急性皮肤冷却持续增加EMG，BAT温度和心率，这些反应通过纳米注射蝇蕈醇抑制正中视前核（MnPO）中的神经元而消除。刺激MnPO可引起震颤、BAT产热和心动过速，这些都可通过拮抗内侧视前区（MPO）的GABA（A）受体而逆转。用蝇蕈醇抑制背内侧下丘脑（DMH）或中缝苍白核（rRPa）中的神经元或用8-OH-DPAT激活rRPa中的5-HT 1A受体，消除了皮肤冷却或将前列腺素（PG）E-2（一种致热介质）纳米注射到MPO中引起的颤抖、BAT产热、心动过速和升压反应。这些数据总结了一个示意性的模型，在该模型中，颤抖以及对寒冷防御和发热的交感神经反应是由下行兴奋性信号通过DMH和rRPa驱动的，该信号是在视前区的局部回路的紧张性抑制控制下的。这些结果提供了一个有趣的概念，即在增加产热水平的需求下，平行的中枢传出通路控制躯体和交感运动系统来驱动产热。
Shivering is a remarkable somatomotor thermogenic response that is controlled by brain mechanisms. We recorded EMGs in anaesthetized rats to elucidate the central neural circuitry for shivering and identified several brain regions whose thermoregulatory neurons comprise the efferent pathway driving shivering responses to skin cooling and pyrogenic stimulation. We simultaneously monitored parameters from sympathetic effectors: brown adipose tissue (BAT) temperature for non-shivering thermogenesis and arterial pressure and heart rate for cardiovascular responses. Acute skin cooling consistently increased EMG, BAT temperature and heart rate and these responses were eliminated by inhibition of neurons in the median preoptic nucleus (MnPO) with nanoinjection of muscimol. Stimulation of the MnPO evoked shivering, BAT thermogenesis and tachycardia, which were all reversed by antagonizing GABA(A) receptors in the medial preoptic area (MPO). Inhibition of neurons in the dorsomedial hypothalamus (DMH) or rostral raphe pallidus nucleus (rRPa) with muscimol or activation of 5-HT1A receptors in the rRPa with 8-OH-DPAT eliminated the shivering, BAT thermogenic, tachycardic and pressor responses evoked by skin cooling or by nanoinjection of prostaglandin (PG) E-2, a pyrogenic mediator, into the MPO. These data are summarized with a schematic model in which the shivering as well as the sympathetic responses for cold defence and fever are driven by descending excitatory signalling through the DMH and the rRPa, which is under a tonic inhibitory control from a local circuit in the preoptic area. These results provide the interesting notion that, under the demand for increasing levels of heat production, parallel central efferent pathways control the somatic and sympathetic motor systems to drive thermogenesis.