Abstract

The existence of a magnetic compass system allowing animals to maintain the direction of their migratory journeys was first shown in birds about fifty years ago. Over the past half century, a large amount of indirect, mainly behavioral, data on the features of the avian magnetic compass and its relationship with the perception of light has been obtained. Based on these data, the dominant idea suggests that the primary magnetoreceptor in birds is located in the retina, and the most popular hypothesis concerning operation of such a magnetoreceptor is the radical pair model. According to this model, the primary receptor molecules that perceive the magnetic field are cryptochromes expressed in the neurons of the avian retina. It is assumed that cryptochrome molecules localized in photoreceptor cells may have an ordered orientation relative to the retina plane. When photons are absorbed in the short wavelength range of the spectrum, cryptochromes would produce a chemical response depending on the direction of the external magnetic field. The sensitivity of photochemical reactions involving radical pairs in cryptochromes to a magnetic field is confirmed both by theoretical calculations and experimentally. However, up to date there is no experimental data obtained on the molecular mechanisms of further transduction of signal induced by a magnetic field. The existing hypotheses on the possible nature of these mechanisms have some issues concerning their compatibility with the current concepts of the photoreception. These hypotheses ascribe special properties to the participants of the visual process both at the molecular and at the cellular level, which has not yet been proved experimentally. Thus, nowadays the science of magnetoreception is posed to consistently test the existing hypotheses on the molecular basis of avian magnetic compass.

中文翻译：

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禽磁罗盘与光感受之间的关系：假设和未解决的问题。

摘要

大约在50年前的鸟类中首次发现了磁性罗盘系统的存在，它可以使动物保持其迁徙的方向。在过去的半个世纪中，已获得了大量有关禽磁罗盘特征及其与光的感知之间关系的间接数据，主要是行为数据。根据这些数据，主要观点认为鸟类中的主要磁感受器位于视网膜中，关于这种磁感受器操作的最流行的假设是自由基对模型。根据该模型，感知磁场的主要受体分子是在禽视网膜神经元中表达的隐色染料。假设位于感光细胞中的隐色分子可能相对于视网膜平面有序排列。当光子在光谱的短波长范围内被吸收时，隐色染料将根据外部磁场的方向产生化学响应。理论计算和实验均证实了涉及隐色染料中的自由基对的光化学反应对磁场的敏感性。然而，迄今为止，还没有获得关于由磁场感应的信号进一步转导的分子机制的实验数据。关于这些机制的可能性质的现有假设存在一些问题，这些问题涉及它们与光接收的当前概念的兼容性。这些假设在分子水平和细胞水平都赋予了视觉过程参与者特殊的性质，这还没有通过实验得到证明。因此，如今，磁接收科学被认为可以在禽类磁罗盘的分子基础上一致地检验现有的假设。