Cranial endothermy and a putative brain heater in the most basal tuna species, Allothunnus fallai
Cranial endothermy and a putative brain heater in the most basal tuna species, Allothunnus fallai
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DOI：
10.1111/j.1095-8649.2007.01446.x
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发表时间：
2007-06
影响因子：
2
通讯作者：
C. Sepulveda;K. Dickson;L. Frank;J. Graham
中科院分区：
文献类型：
--
作者：
C. Sepulveda;K. Dickson;L. Frank;J. Graham
对细长的金枪鱼的野外研究表明，颅骨温度为4·8±0·4°C（平均值±S.D。），旨在记录颅外热源的剖腹产。这种基本的金枪鱼的大脑在结构上与A. fallai的任何其他鱼类物种不同。肌肉对（上，下，培养基和侧直肠）被纳入一个不同的组织复合物中，该组织位于轨道之间，并直接与脑壳接触。 ，使用高分辨率的磁共振成像来说明其与大脑和视神经的关联。蛋白质由颈动脉内部动脉，动脉 - 静脉配置以及全身循环和温暖的眼睛肌肉之间的蛋白质灌注。总的来说，这些发现表明，A. fallai已经进化出了外的肌肉，这可能会使大脑和眼睛区域变暖。修饰完成了所有四个直肠肌肉，并且唯一记录了这种机制在金枪鱼中进行颅骨的渗透机制。
Field studies on the slender tuna Allothunnus fallai revealed cranial temperatures that were 4·8 ± 0·4° C (mean ±s.d.) above the ambient sea surface temperature. Dissections aimed at documenting the cranial heat source revealed a fused extraocular muscle complex positioned beneath the brain of this basal tuna species. The muscle complex is structurally distinct from that documented for any other fish species. In A. fallai, all four extraocular rectus muscle pairs (superior, inferior, medial and lateral rectus) are incorporated into one distinct tissue complex which is positioned between the orbits and in direct contact with the braincase. A combination of morphological, physiological and biochemical techniques were used to characterize the modified muscle tissue, and high-resolution magnetic resonance imaging was used to illustrate its association with the brain and optic nerves. The modified eye muscles lack organized contractile proteins and are perfused by an extensive vascular counter-current system that originates from the internal carotid artery. Vessel diameters, artery–vein configuration, and anatomic position between the systemic circulation and the warm eye muscles all suggest that this system is a heat exchanger. Collectively, these findings suggest that A. fallai has evolved extraocular muscles that may function to warm the brain and eye region. This is the first record of a cranial modification comprised of all four rectus muscles and the only documented occurrence of this mechanism for cranial endothermy among the tunas.