Lee J K, Strausfeld N J
Division of Neurobiology, University of Arizona, Tucson 85721.
J Neurocytol. 1990 Aug;19(4):519-38. doi: 10.1007/BF01257241.
Distribution and neuronal organization of sensilla on the surface of the annulate flagellar segment of the antenna of the male Manduca sexta were studied by scanning and transmission electron microscopy. Nine types of sensilla were identified and their bipolar neurons ascribed to specific sensory modalities on the basis of their cuticular and dendritic morphology. Cuticle morphology identifies two types of sensilla trichodea, two types of sensilla basiconica and one type of sensillum coeloconicum. Certain of these olfactory sensilla are further subdivided on the basis of their dendritic structures. One type of sensillum chaeticum was interpreted as a contact chemoreceptor. A second type of sensillum coeloconicum and a styliform sensilla complex were interpreted as bimodal hygro- and thermosensilla. A second species of sensillum chaeticum serves mechanosensation. Counts from annuli situated about midway along the flagellum revealed a total of about 2200 sensilla supplied by approximately 5160 sensory neurons. A conservative estimate suggests that a male antenna with 85-90 annuli provides the flagellar nerve with at least 3.6 x 10(5) receptor axons, a number that exceeds previous estimates by almost 50% Each species of receptor has a characteristic location on the annulus. Of the 2100 or so sensilla situated on the dorsal, ventral and the leading edge surfaces, about 800 consist of male-specific type-I trichoids containing pheromone-sensitive receptors. Arciform arrays of these sensilla on the upper and lower surfaces of each annulus presumably optimize the capture and absorption of odour molecules. The trailing edge of the flagellum, which is thickly covered by scales and was assumed until now to lack receptors, contains both mechanosensitive and contact chemoreceptors. The modality of non-olfactory receptors is considered with respect to similar elements that have been functionally identified in other species. The coexistence of non-olfactory sensilla with olfactory elements is discussed with respect to current knowledge of the organization of olfactory centres in the brain.
通过扫描电子显微镜和透射电子显微镜，研究了烟草天蛾雄性触角环鞭节表面感器的分布和神经元组织。基于其表皮和树突形态，鉴定出九种类型的感器，并将其双极神经元归为特定的感觉模式。表皮形态确定了两种毛形感器、两种锥形感器和一种腔锥感器。其中某些嗅觉感器根据其树突结构进一步细分。一种刺形感器被解释为接触化学感受器。第二种腔锥感器和一种针形感器复合体被解释为双模态湿敏和热敏感器。第二种刺形感器用于机械感受。对鞭节中部附近环纹上的感器计数显示，共有约2200个感器，由约5160个感觉神经元提供。保守估计表明，具有85 - 90个环纹的雄性触角为鞭神经提供至少3.6×10⁵条受体轴突，这一数字比之前的估计高出近50%。每种受体在环纹上都有一个特征位置。在位于背、腹和前缘表面的约2100个感器中，约800个由含有信息素敏感受体的雄性特异性I型毛形感器组成。这些感器在每个环纹的上表面和下表面呈弧形排列，大概可以优化气味分子的捕获和吸收。鞭节的后缘被鳞片密集覆盖，直到现在一直被认为没有受体，但实际上含有机械敏感和接触化学感受器。关于在其他物种中已在功能上鉴定出的类似元件，对非嗅觉受体的模式进行了考虑。关于大脑中嗅觉中枢组织的现有知识，讨论了非嗅觉感器与嗅觉元件的共存情况。
