Liguori G, Paino S, Mirabella N, Squillacioti C, De Luca A, Vittoria A
Department of Biological Structures, Functions and Technologies, University of Naples Federico II, Via Veterinaria 1, I-80137, Naples, Italy.
Anat Histol Embryol. 2014 Feb;43(1):42-7. doi: 10.1111/ahe.12046. Epub 2013 Mar 25.
Orexins A (ox A) and B are two peptides originally discovered in neurons of rat hypothalamus, and later found in different cellular types of the gastrointestinal and genital tracts. They arise from the proteolytic cleavage of a common precursor molecule, prepro-orexin, and bind to two receptors, namely receptor 1 (ox1r) and receptor 2 for orexins, that show different binding affinity. The central role of the two peptides has been extensively studied, whereas their activity in the periphery is still poorly known. Here, we investigated the presence of ox A and ox1r in the epididymis of a South American camelid species, the alpaca, by immunohistochemistry, and we also assessed the expression of prepro-orexin and ox1r in tissue extracts by Western blotting analysis. Ox A- and ox1r-immunoreactivity was found in the cytoplasm of principal cells of the caput epididymis. A prevalent supranuclear localization of granular-shaped positive material was observed. No positivity was present in the other cytotypes of epididymis. The expression of two peptides with molecular weight corresponding to those of prepro-orexin and ox1r, respectively, was detected in the tissue extracts from the organ.
食欲素A（ox A）和食欲素B是最初在大鼠下丘脑神经元中发现的两种肽，后来在胃肠道和生殖道的不同细胞类型中也被发现。它们由一种共同的前体分子——前食欲素原经蛋白水解切割产生，并与两种受体结合，即食欲素受体1（ox1r）和食欲素受体2，这两种受体表现出不同的结合亲和力。这两种肽的核心作用已得到广泛研究，而它们在外周组织中的活性仍鲜为人知。在此，我们通过免疫组织化学研究了南美骆驼科动物羊驼附睾中ox A和ox1r的存在情况，并且还通过蛋白质印迹分析评估了组织提取物中前食欲素原和ox1r的表达。在附睾头主细胞的细胞质中发现了ox A和ox1r免疫反应性。观察到颗粒状阳性物质主要位于细胞核上方。在附睾的其他细胞类型中未发现阳性反应。在该器官的组织提取物中检测到了分子量分别与前食欲素原和ox1r相对应的两种肽的表达。
