Molecular neurobiological studies on the taste reception in Drosophila.

在果蝇中，味觉受体神经元（GRNs）存在于位于前胸腿和唇瓣上的称为感受器的毛发状结构中。大多数味觉感受器都有四种GRN，它们根据对基本刺激的敏感性而命名：水（W细胞），糖（S细胞），低浓度盐（L1细胞）和高浓度盐（L2细胞）。我们第一次发现，几个味觉感受器上的前胸腿检测苦味化合物通过激活特定的味觉神经元，但也通过抑制的味觉神经元激活的糖和水。使用一种新的统计方法的基础上的分析interspike间隔，我们表明，苦味化合物激活L2细胞。它们对苦味化合物的敏感性在感受器之间是不同的，这表明苦味化合物的特异性受体在L2细胞中差异表达。根据其长度和位置，将唇瓣味感器分为l-型、s-型和i-型。我们记录了三种感受器对糖、盐和苦味化合物的神经反应。我们发现s型和i型感受器对苦味化合物有反应。l型和s型唇瓣感受器有四个细胞，而大多数i型感受器只有两个GRN。在i型感器中，我们证明了第一个GRN对糖和低浓度盐有反应。第二个GRN检测一系列苦味化合物，其中士的宁是最有效的;也检测高浓度的盐。这两种类型的GRN响应水

In Drosophila, gustatory receptor neurons (GRNs) occur within hair-like structures called sensilla located on prothoracic legs and labellum. Most taste sensilla house four GRNs, which have been named according to their preferred sensitivity to basic stimuli : water (W cell), sugars (S cell), salt at low concentration (L1 cell), and salt at high concentration (L2 cell). We showed for the first time that several taste sensilla on the prothoracic legs detect bitter compounds both through the activation of specific taste neurons but also through inhibition of taste neurons activated by sugars and water. Using a new statistical approach based on the analysis of interspike intervals, we showed that bitter compounds activate the L2 cell. Their sensitivity to bitter compounds was different between sensilla, suggesting that specific receptors to bitter compounds are differentially expressed among L2 cells. Labellar taste sensilla are classified into three types, l-,s-, and i-type, according to their length and location. We recorded the nerve responses from all the three types of sensilla to sugars, salts and bitter compound. We found that s- and i-type sensilla respond to bitter compounds. l- and s-type labellar sensilla possess four cells, while most i-type sensilla house only two GRNs. In i-type sensilla, we demonstratd that the first GRN responds to sugar and to low concentrations of salt. The second GRN detects a range of bitter compounds, among which strychnine is the most potent ; and also to salt at high concentrations. Neither type of GRN responds to water