Transient Receptor Potential Ion Channels Control Thermoregulatory Behaviour in Reptiles
Transient Receptor Potential Ion Channels Control Thermoregulatory Behaviour in Reptiles
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DOI：
10.1371/journal.pone.0000281
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发表时间：
2007-03-14
期刊：
影响因子：
3.7
通讯作者：
Murray, Shauna A.
中科院分区：
文献类型：
--
作者：
Seebacher, Frank;Murray, Shauna A.
生物功能受热力学控制，动物调节体温以优化细胞性能并避免有害的极端情况。感知环境和内部温度的能力是体温调节进化的先决条件。然而，使变温脊椎动物能够感知热量的机制仍然未知。最近发现的瞬时受体电位离子通道（TRP）的热特性，使这些蛋白质适合作为温度传感器。在这里，我们测试的假设，TRP存在于爬行动物和功能，以控制体温调节行为。我们发现，热敏感TRPV1的表达在鳄鱼（Crocodylus porosus），琼脂（Amphibolurus muricatus）和scincid（Pseudemoia entrecasteauxii）蜥蜴，以及鹌鹑和斑胸草雀（Coturnix chinensis和Poephila guttata）。来自所有爬行动物的TRPV1基因形成一个独特的进化枝，该进化枝通过插入两个氨基酸从哺乳动物和祖先爪蟾序列中描绘出来。TRPV1和冷感TRPM8在鳄鱼的肝脏、肌肉（横棘肌复合体）和心脏组织中表达，并有可能充当内部温度计和外部温度传感器。抑制C. porosus废除了典型的爬行动物在冷却和加热环境之间的穿梭行为，并导致显著改变的体温模式。我们的研究结果提供了近似的机制，热选择在陆地外温动物，这预示着一个根本性的变化解释，因为TRP提供了一个组织特异性输入到动物的体温调节反应的机制。
Biological functions are governed by thermodynamics, and animals regulate their body temperature to optimise cellular performance and to avoid harmful extremes. The capacity to sense environmental and internal temperatures is a prerequisite for the evolution of thermoregulation. However, the mechanisms that enable ectothermic vertebrates to sense heat remain unknown. The recently discovered thermal characteristics of transient receptor potential ion channels (TRP) render these proteins suitable to act as temperature sensors. Here we test the hypothesis that TRPs are present in reptiles and function to control thermoregulatory behaviour. We show that the hot-sensing TRPV1 is expressed in a crocodile (Crocodylus porosus), an agamid (Amphibolurus muricatus) and a scincid (Pseudemoia entrecasteauxii) lizard, as well as in the quail and zebrafinch (Coturnix chinensis and Poephila guttata). The TRPV1 genes from all reptiles form a unique clade that is delineated from the mammalian and the ancestral Xenopus sequences by an insertion of two amino acids. TRPV1 and the cool-sensing TRPM8 are expressed in liver, muscle (transversospinalis complex), and heart tissues of the crocodile, and have the potential to act as internal thermometer and as external temperatures sensors. Inhibition of TRPV1 and TRPM8 in C. porosus abolishes the typically reptilian shuttling behaviour between cooling and heating environments, and leads to significantly altered body temperature patterns. Our results provide the proximate mechanism of thermal selection in terrestrial ectotherms, which heralds a fundamental change in interpretation, because TRPs provide the mechanism for a tissue-specific input into the animals' thermoregulatory response.