COMPARATIVE DISTRIBUTION OF 2[I-125]IODOMELATONIN BINDING IN THE BRAINS OF DIURNAL BIRDS - OUTGROUP ANALYSIS WITH TURTLES
COMPARATIVE DISTRIBUTION OF 2[I-125]IODOMELATONIN BINDING IN THE BRAINS OF DIURNAL BIRDS - OUTGROUP ANALYSIS WITH TURTLES
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DOI：
10.1159/000113553
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发表时间：
1995-05-01
影响因子：
1.7
通讯作者：
KELM, TA
中科院分区：
文献类型：
--
作者：
CASSONE, VM;BROOKS, DS;KELM, TA
松果体及其激素褪黑激素在调节昼夜节律和光周期中的作用在脊椎动物中各不相同。最近，通过应用放射性碘标记的褪黑激素激动剂2[I-125]iodomelatonin（IMEL）的体外结合和放射自显影，在几种鸟类和哺乳动物中阐明了褪黑激素作用的推定位点。在哺乳动物、鸟类和爬行动物中的这些研究表明，这些不同群体之间的IMEL结合分布存在深刻差异，这表明结合的这些巨大差异可能反映了褪黑激素功能的差异。进行本研究，以系统地确定是否在鸟类物种之间的IMEL结合的变化对应于昼夜节律的组织和/或系统发育关系的变化。使用体外结合、放射自显影和计算机辅助图像分析，在来自5个目（鹦鹉形目、雀形目、鸽形目、鸡形目和雁形目）的14个不同物种的鸟类的脑中确定特异性IMEL结合的分布。该分布与3种海龟作为外群的类似研究进行了比较。这些数据表明，IMEL结合在所有鸟类的昼夜节律，离顶盖，离丘脑和辅助光学视觉通路的retinorecipient结构。然而，中继核和离顶盖、离丘脑、辅助视神经和边缘系统的整合结构在不同程度上束缚了激素。在海龟中，在离丘脑视觉通路的retinorecipient结构和离顶盖视觉通路的retinorecipient和整合区中观察到结合。在任何禽类或龟类动物的松果体、下丘脑结节或腺垂体中均未观察到结合。这种分布是从哺乳动物中观察到的，其中结合占主导地位的腺垂体和视交叉上核的结节，表明昼夜节律系统可能会影响广泛的感觉和综合功能的鸟类和爬行动物通过昼夜分泌褪黑激素，但这种能力已经失去了哺乳动物中的显着不同。
The roles that the pineal gland and its hormone melatonin play in the regulation of circadian rhythmicity and photoperiodism vary among vertebrate species. Recently, putative sites of melatonin action have been elucidated in several avian and mammalian species by application of in vitro binding of a radioiodinated melatonin agonist, 2[I-125]iodomelatonin (IMEL) and autoradioradiography. These studies in mammals, birds and reptiles have indicated profound differences in the distribution of IMEL binding between these diverse groups, suggesting that these large differences in binding may reflect differences in melatonin function. The present study was performed to determine systematically whether the variance in IMEL binding among avian species corresponds to changes in circadian organization and/or phylogenetic relationships. The distribution of specific IMEL binding was determined in the brains from birds belonging to 14 different species in 5 Orders (Psittaciformes, Passeriformes, Columbiformes, Galliformes and Anseriformes) using in vitro binding, autoradiography and computer-assisted image analysis. The distribution was compared to a similar study in 3 species of turtles as an outgroup. The data indicated IMEL binding in retinorecipient structures of the circadian, tectofugal, thalamofugal and accessory optic visual pathways in all avian species. Relay nuclei and integrative structures of the tectofugal, thalamofugal, accessory optic, and limbic systems, however, bound the hormone to varying degrees. In turtles, binding was observed in retinorecipient structures of the thalamofugal visual pathway and in retinorecipient and integrative areas of the tectofugal visual pathway. No binding was observed in the pineal gland, tuberal hypothalamus or adenohypophysis in any avian or testudine species. This distribution is drastically different from that observed in mammals, where binding predominates in the pacs tuberalis of the adenohypophysis and in the suprachiasmatic nucleus, suggesting that the circadian system may influence a wide array of sensory and integrative functions in birds and reptiles through the circadian secretion of melatonin, but that this capacity has been lost in mammals.