Weiss Linnea A, Dahanukar Anupama, Kwon Jae Young, Banerjee Diya, Carlson John R
Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103, USA.
Neuron. 2011 Jan 27;69(2):258-72. doi: 10.1016/j.neuron.2011.01.001.
The extent of diversity among bitter-sensing neurons is a fundamental issue in the field of taste. Data are limited and conflicting as to whether bitter neurons are broadly tuned and uniform, resulting in indiscriminate avoidance of bitter stimuli, or diverse, allowing a more discerning evaluation of food sources. We provide a systematic analysis of how bitter taste is encoded by the major taste organ of the Drosophila head, the labellum. Each of 16 bitter compounds is tested physiologically against all 31 taste hairs, revealing responses that are diverse in magnitude and dynamics. Four functional classes of bitter neurons are defined. Four corresponding classes are defined through expression analysis of all 68 gustatory taste receptors. A receptor-to-neuron-to-tastant map is constructed. Misexpression of one receptor confers bitter responses as predicted by the map. These results reveal a degree of complexity that greatly expands the capacity of the system to encode bitter taste.
苦味感知神经元之间的多样性程度是味觉领域的一个基本问题。关于苦味神经元是广泛调谐且统一的，从而导致对苦味刺激不加区分地回避，还是具有多样性，从而能够对食物来源进行更有辨别力的评估，数据有限且相互矛盾。我们对果蝇头部主要味觉器官唇叶如何编码苦味进行了系统分析。16种苦味化合物中的每一种都针对所有31根味觉毛进行了生理测试，揭示了在幅度和动态方面各不相同的反应。定义了四类功能性苦味神经元。通过对所有68种味觉受体进行表达分析，定义了四类相应的受体。构建了一个受体-神经元-味觉剂图谱。一种受体的错误表达赋予了如该图谱所预测的苦味反应。这些结果揭示了一定程度的复杂性，极大地扩展了该系统编码苦味的能力。
