The biology of fish olfaction: amino acids and Ga-proteins

嗅觉是生物体从环境中收集信息的主要途径。外部线索可以引发一系列不同的反应，从内部的生理调整到复杂的行为。在鱼类中，溶解的氨基酸对许多行为都是必不可少的，从食物位置到躲避捕食者，再到迁徙。目前我们知道，氨基酸可以被三个形态不同的感觉神经元检测到，但尚不清楚这些不同的神经元是如何协同工作来引起行为反应的。我研究的中心目标是帮助解决这个嗅觉难题，通过表征哪种类型的嗅觉感觉神经元感受器对哪种气味做出反应，最终唤起给定的结果？ 我的长期研究有三个目标：i)将嗅觉感受器与气味及其引起的有机反应联系起来；ii)探索当对嗅觉的要求不同时，这些关系在鱼类的生命周期中可能会发生什么变化；iii)确定嗅觉受损在这些生命周期中的影响。本Discovery计划书详细说明了实现这些目标的两个第一步。首先，为了将气味与受体联系起来，需要一条途径来集中研究鱼类拥有的~150受体的一个子集。我建议暂时禁用将气味感受器与细胞反应联系起来的机制，因为这实际上将感受器分为四组。这些群体似乎也与不同生物体水平的反应有关。其次，需要一种方法来检测气味-感受器配对会唤起什么。由于许多气味都能引起运动，我的研究将探索气味是如何引起不同类型的活动的。这项研究还将探索气味感知的变化如何影响游泳活动，因为许多天然和合成试剂会削弱嗅觉。这项资助是关于氨基酸对鱼类嗅觉的重要性，更广泛地说，它是关于如何感知和使用复杂的信号来引导动物通过当前环境不断变化的性质。

The sense of smell (olfaction) is a major route by which organisms gather information from their environment. The external cues can induce a diverse array of responses, ranging from internal physiological adjustments to complex behaviours. In fish, dissolved amino acids are essential do numerous behaviours, ranging from food location, to predator avoidance, to migration. At present we know that amino acids can be detected by three morphologically distinct sensory neurons, but what is not known is how these different neurons work together to evoke behavioural responses. The central goal of my research is to help solve this olfactory puzzle, by characterizing what type of olfactory sensory neuron receptor responds to which odorant to eventually evoke a given outcome? My long-term research has three objectives: i) to link olfactory receptors to odours and the organismal responses they evoke, ii) to explore how these relationships may change during the lifecycle of a fish when varying demands are placed on olfaction, and iii) to determine the ramifications of impaired olfaction over such lifecycles. This Discovery proposal details two first steps to meet these objectives. Firstly, in order to link odours to receptors, a pathway is needed to focus research on a subset of the ~150 receptors fish have. I propose to temporarily disable the machinery that links odour receptors to cellular responses as this effectively divides the receptors into four groups. These groups also appear to be associated with different organism-level responses. Secondly, a method is needed to detect what an odour-receptor pairing evokes. As many odours evoke motion, my research will explore how odours evoke different types of activities. The research will also explore how changes in odour perception affect swimming activity, as many natural and synthetic agents impair olfaction. This grant is about the importance of amino acids to olfaction in fishes, and more broadly, it is about how complex signals are perceived and used to direct animals through the changing nature of the present environment.