Ecological, evolutionary, and functional correlates of sensilla number and glomerular density in the olfactory system of decapod crustaceans
Ecological, evolutionary, and functional correlates of sensilla number and glomerular density in the olfactory system of decapod crustaceans
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DOI：
10.1002/cne.10474
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发表时间：
2003-01-06
影响因子：
2.5
通讯作者：
Sandeman, DC
中科院分区：
文献类型：
--
作者：
Beltz, BS;Kordas, K;Sandeman, DC
脊椎动物和无脊椎动物嗅觉系统的共同特征之一是将初级加工区分为不同的突触神经元簇，称为肾小球。嗅球似乎作为嗅觉的功能单位，是化学感觉传入和二级神经元之间的初级处理的位置。尽管肾小球在所有门中都有发现，但它们的数量和大小似乎是每个物种的特征，这引起了肾小球数量和功能之间存在关系的猜测。例如，有人假设肾小球较多的动物可能能够分辨更广泛的气味。甲壳类物种分布在淡水，海洋和陆地栖息地在北极，温带和热带气候。他们还表现出各种各样的生活方式和行为，其中嗅觉可能发挥主导作用。例如，摄食的范围从肉食性的，通过水下和陆地杂食性的清除，到过滤器摄食。交配和领土行为也被认为涉及化学信号。目前的研究探讨了17种甲壳类动物的嗅叶中的小球数量，这些甲壳类动物来自爬行类十足类中的7个类群中的6个。肾小球数目的估计值是从用抗突触蛋白的抗体免疫细胞化学处理的切片材料的分析中获得的，该抗体标记神经元末端中包含的蛋白质。在不同物种中发现的肾小球的数量，然后比较肾小球神经元的体积，嗅觉感受器的数量，生活方式，栖息地和系统发育的亲和力。从这些相关性中出现的画面是，十足类甲壳动物在构建其嗅觉系统时采用了各种策略，其中大小，敏感性和选择性的问题都相互作用。我们发现一个连续的群体，从那些有利于高度收敛的受体神经元到少数肾小球的那些共享少数受体神经元之间的许多肾小球。这些差异的潜在功能后果进行了讨论。
One of the features common among olfactory systems for vertebrate and invertebrate species is the division of the primary processing area into distinct clumps of synaptic neuropil, called glomeruli. The olfactory glomeruli appear to serve as functional units of olfaction and are the location of the primary processing between chemosensory afferents and second-order neurons. Although glomeruli are found across all phyla, their numbers and size appear to be characteristic for each species, giving rise to the speculation that there is a relationship between glomerular number and function. It has been hypothesized, for example, that animals with more glomeruli may be able to resolve a wider range of odors. Crustacean species are distributed among freshwater, marine, and terrestrial habitats in arctic, temperate, and tropical climates. They also exhibit a variety of lifestyles and behaviors in which olfaction may play a dominant role. Feeding, for example, ranges from carnivorous, through subaquatic and terrestrial omnivorous scavenging, to filter feeding. Mating and territorial behaviors also are known to involve chemical signals. The current study examines glomerular numbers in the olfactory lobes of 17 crustacean species from six of the seven taxa now included in the reptantian decapods. Estimates of the glomerular numbers were obtained from the analysis of sectioned material treated immunocytochemically with an antibody against synapsin that labels proteins contained in neuronal terminals. The numbers of glomeruli found in the different species were then compared with the volume of the glomerular neuropil, numbers of olfactory sensilla, life styles, habitat, and phylogenetic affinities. The picture that emerges from these correlations is that the decapod crustaceans have exploited various strategies in the construction of their olfactory systems in which the problems of size, sensitivity, and selectivity have all interacted. We find a continuum across the groups ranging from those that favor a high convergence of receptor neurons onto a few glomeruli to those that share a small number of receptor neurons among many glomeruli. The potential functional consequences of these differences are discussed.