Christensen T A, Harrow I D, Cuzzocrea C, Randolph P W, Hildebrand J G
Arizona Research Laboratories, Division of Neurobiology, University of Arizona, Tucson 85721, USA.
Chem Senses. 1995 Jun;20(3):313-23. doi: 10.1093/chemse/20.3.313.
The central projections of olfactory receptor cells associated with two distinct types of antennal sensilla in the sphinx moth Manduca sexta were revealed by anterograde staining. In both sexes, receptor axons that arise from sexually isomorphic, type-II trichoid sensilla (and possibly some basiconic sensilla) project to the spheroidal glomeruli in the ipsilateral antennal lobe. Each axon terminates in one glomerulus. Axons from a limited region of the antenna project to glomeruli throughout the lobe, arguing against strict topographic mapping of antennal receptor cells onto the array of glomeruli. Axons of sex-pheromone-selective receptor cells in the male-specific type-I trichoid sensilla project exclusively to the sexually dimorphic macroglomerular complex (MGC). Axons from sensilla on the dorsal surface of the antenna are biased toward the medial MGC and those from ventral sensilla, toward the lateral MGC. Some receptor-cell axons branch before reaching the MGC, but their terminals are always confined to one of the two main glomerular divisions of the MGC, the cumulus and toroid. These findings confirm that primary-afferent information about pheromonal and non-pheromonal odors is segregated in the antennal lobe and suggest that there is a functional correspondence between particular olfactory receptor cells and specific glomeruli.
通过顺行染色揭示了烟草天蛾触角上与两种不同类型触角感器相关的嗅觉受体细胞的中枢投射。在两性中，源自性别同型的II型毛形感器（可能还有一些锥形感器）的受体轴突投射到同侧触角叶的球状神经节。每个轴突终止于一个神经节。来自触角有限区域的轴突投射到整个叶的神经节，这与触角受体细胞在神经节阵列上严格的拓扑映射观点相悖。雄性特有的I型毛形感器中对性信息素具有选择性的受体细胞的轴突专门投射到性别二态性的大神经节复合体（MGC）。来自触角背表面感器的轴突偏向内侧MGC，而来自腹侧感器的轴突则偏向外侧MGC。一些受体细胞轴突在到达MGC之前会分支，但其终末总是局限于MGC的两个主要神经节分区之一，即积云状神经节和环形神经节。这些发现证实了关于性信息素和非性信息素气味的初级传入信息在触角叶中是分开的，并表明特定的嗅觉受体细胞与特定的神经节之间存在功能对应关系。
