Abstract：
BACKGROUND: The accessory olfactory bulb (AOB) is the first integrative center of the vomeronasal system (VNS), and the general macroscopic, microscopic, and neurochemical organizational patterns of the AOB differ fundamentally among species. Therefore, the low degree of differentiation observed for the dog AOB is surprising. As the artificial selection pressure exerted on domestic dogs has been suggested to play a key role in the involution of the dog VNS, a wild canid, such as the fox, represents a useful model for studying the hypothetical effects of domestication on the AOB morphology.
METHODS: A comprehensive histological, lectin-histochemical, and immunohistochemical study of the fox AOB was performed. Anti-Gαo and anti-Gαi2 antibodies were particularly useful, as they label the transduction cascade of the vomeronasal receptor types 1 (V1R) and 2 (V2R), respectively. Other employed antibodies included those against proteins such as microtubule-associated protein 2 (MAP-2), tubulin, glial fibrillary acidic protein, growth-associated protein 43 (GAP-43), olfactory marker protein (OMP), calbindin, and calretinin.
RESULTS: The cytoarchitecture of the fox AOB showed a clear lamination, with neatly differentiated layers; a highly developed glomerular layer, rich in periglomerular cells; and large inner cell and granular layers. The immunolabeling of Gαi2, OMP, and GAP-43 delineated the outer layers, whereas Gαo and MAP-2 immunolabeling defined the inner layers. MAP-2 characterized the somas of AOB principal cells and their dendritic trees. Anti-calbindin and anti-calretinin antibodies discriminated neural subpopulations in both the mitral-plexiform layer and the granular cell layer, and the lectin Ulex europeus agglutinin I (UEA-I) showed selectivity for the AOB and the vomeronasal nerves.
CONCLUSIONS: The fox AOB presents unique characteristics and a higher degree of morphological development compared with the dog AOB. The comparatively complex neural basis for semiochemical information processing in the fox compared with that observed in dogs suggests loss of AOB anatomical complexity during the evolutionary history of dogs and opens a new avenue of research for studying the effects of domestication on brain structures.
METHODS: A comprehensive histological, lectin-histochemical, and immunohistochemical study of the fox AOB was performed. Anti-Gαo and anti-Gαi2 antibodies were particularly useful, as they label the transduction cascade of the vomeronasal receptor types 1 (V1R) and 2 (V2R), respectively. Other employed antibodies included those against proteins such as microtubule-associated protein 2 (MAP-2), tubulin, glial fibrillary acidic protein, growth-associated protein 43 (GAP-43), olfactory marker protein (OMP), calbindin, and calretinin.
RESULTS: The cytoarchitecture of the fox AOB showed a clear lamination, with neatly differentiated layers; a highly developed glomerular layer, rich in periglomerular cells; and large inner cell and granular layers. The immunolabeling of Gαi2, OMP, and GAP-43 delineated the outer layers, whereas Gαo and MAP-2 immunolabeling defined the inner layers. MAP-2 characterized the somas of AOB principal cells and their dendritic trees. Anti-calbindin and anti-calretinin antibodies discriminated neural subpopulations in both the mitral-plexiform layer and the granular cell layer, and the lectin Ulex europeus agglutinin I (UEA-I) showed selectivity for the AOB and the vomeronasal nerves.
CONCLUSIONS: The fox AOB presents unique characteristics and a higher degree of morphological development compared with the dog AOB. The comparatively complex neural basis for semiochemical information processing in the fox compared with that observed in dogs suggests loss of AOB anatomical complexity during the evolutionary history of dogs and opens a new avenue of research for studying the effects of domestication on brain structures.
摘要：
背景：辅助嗅球（AOB）是vomeronasal系统（VNS）的第一个整合中心，和一般的宏观，微观,AOB的神经化学组织模式在物种之间存在根本差异。因此,观察到的狗AOB的低分化程度是令人惊讶的。由于对家犬施加的人工选择压力已被认为在狗VNS的退化中起关键作用，一只野生犬科动物,比如狐狸，代表了研究驯化对AOB形态的假设影响的有用模型。
方法：综合组织学，凝集素-组织化学,并对狐狸AOB进行了免疫组织化学研究。抗Gαo和抗Gαi2抗体特别有用，因为它们标记了1型(V1R)和2型(V2R)受体的转导级联，分别。其他使用的抗体包括针对蛋白质的抗体，例如微管相关蛋白2（MAP-2），微管蛋白,胶质纤维酸性蛋白，生长相关蛋白43（GAP-43），嗅觉标记蛋白（OMP），Calbindin,还有卡列丁.
结果：狐狸AOB的细胞结构显示出清晰的层状结构，有整齐的分化层；高度发达的肾小球层，富含肾小球周围细胞；和大的内部细胞和颗粒层。Gαi2，OMP的免疫标记，GAP-43描绘了外层，而Gαo和MAP-2免疫标记定义了内层。MAP-2表征了AOB主细胞及其树突树的体细胞。抗钙结合蛋白和抗钙视网膜素抗体可区分二尖瓣丛状层和颗粒细胞层中的神经亚群，凝集素Europeus凝集素I（UEA-I）对AOB和犁鼻神经具有选择性。
结论：与狗AOB相比，狐狸AOB具有独特的特征和更高的形态发育程度。与在狗中观察到的相比，狐狸的信息素化学信息处理的神经基础相对复杂，这表明在狗的进化史中AOB解剖复杂性的丧失，并为研究驯化对大脑结构的影响开辟了一条新的研究途径。
方法：综合组织学，凝集素-组织化学,并对狐狸AOB进行了免疫组织化学研究。抗Gαo和抗Gαi2抗体特别有用，因为它们标记了1型(V1R)和2型(V2R)受体的转导级联，分别。其他使用的抗体包括针对蛋白质的抗体，例如微管相关蛋白2（MAP-2），微管蛋白,胶质纤维酸性蛋白，生长相关蛋白43（GAP-43），嗅觉标记蛋白（OMP），Calbindin,还有卡列丁.
结果：狐狸AOB的细胞结构显示出清晰的层状结构，有整齐的分化层；高度发达的肾小球层，富含肾小球周围细胞；和大的内部细胞和颗粒层。Gαi2，OMP的免疫标记，GAP-43描绘了外层，而Gαo和MAP-2免疫标记定义了内层。MAP-2表征了AOB主细胞及其树突树的体细胞。抗钙结合蛋白和抗钙视网膜素抗体可区分二尖瓣丛状层和颗粒细胞层中的神经亚群，凝集素Europeus凝集素I（UEA-I）对AOB和犁鼻神经具有选择性。
结论：与狗AOB相比，狐狸AOB具有独特的特征和更高的形态发育程度。与在狗中观察到的相比，狐狸的信息素化学信息处理的神经基础相对复杂，这表明在狗的进化史中AOB解剖复杂性的丧失，并为研究驯化对大脑结构的影响开辟了一条新的研究途径。
