González-Martínez D, Madigou T, Zmora N, Anglade I, Zanuy S, Zohar Y, Elizur A, Muñoz-Cueto J A, Kah O
Departamento de Biología Animal, Vegetal y Ecología, Facultad de Ciencias del Mar, Universidad de Cádiz, 11510 Puerto Real, Spain.
J Comp Neurol. 2001 Jan 1;429(1):144-55. doi: 10.1002/1096-9861(20000101)429:1<144::aid-cne11>3.0.co;2-b.
The expression sites of three prepro-gonadotrophin-releasing hormones (GnRHs), corresponding to seabream GnRH (sbGnRH: Ser(8)-mGnRH, mammalian GnRH), salmon GnRH (sGnRH: Trp(7)Leu(8)-mGnRH), and chicken GnRH-II (cGnRH-II: His(5)Trp(7)Tyr(8)-mGnRH) forms were studied in the brain of a perciform fish, the European sea bass (Dicentrarchus labrax) by means of in situ hybridization. The riboprobes used in this study correspond to the three GnRH-associated peptide (GAP)-coding regions of the prepro-GnRH cDNAs cloned from the same species (salmon GAP: sGAP; seabream GAP: sbGAP; chicken GAP-II: cIIGAP), which show little oligonucleotide sequence identity (sGAP versus sbGAP: 42%; cIIGAP versus sbGAP: 36%; sGAP versus cIIGAP: 41%). Adjacent paraffin sections (6 mm) throughout the entire brain were treated in parallel with each of the three anti-sense probes and the corresponding sense probes, demonstrating the high specificity of the hybridization signal. The results showed that both sGAP and sbGAP mRNAs had a broader expression in the olfactory bulbs, ventral telencephalon, and preoptic region, whereas cIIGAP mRNA expression was confined to large cells of the nucleus of the medial longitudinal fascicle. In the olfactory bulbs, both the signal intensity and the number of positive cells were higher with the sGAP probe, whereas sbGAP mRNA-expressing cells were more numerous and intensely stained in the preoptic region. Additional isolated sbGAP-positive cells were detected in the ventrolateral hypothalamus. These results demonstrate a clear overlapping of sGAP- and sbGAP-expressing cells in the forebrain of the European sea bass, in contrast to previous reports in other perciforms showing a clear segregation of these two cell populations.
采用原位杂交技术，研究了三种前促性腺激素释放激素（GnRH），即对应于海鲷GnRH（sbGnRH：Ser(8)-mGnRH，哺乳动物GnRH）、鲑鱼GnRH（sGnRH：Trp(7)Leu(8)-mGnRH）和鸡GnRH-II（cGnRH-II：His(5)Trp(7)Tyr(8)-mGnRH）形式，在鲈形目鱼类欧洲海鲈（Dicentrarchus labrax）脑中的表达位点。本研究中使用的核糖探针对应于从同一物种克隆的前体促性腺激素释放激素cDNA的三个GnRH相关肽（GAP）编码区（鲑鱼GAP：sGAP；海鲷GAP：sbGAP；鸡GAP-II：cIIGAP），它们的寡核苷酸序列同一性较低（sGAP与sbGAP：42%；cIIGAP与sbGAP：36%；sGAP与cIIGAP：41%）。对整个大脑的相邻石蜡切片（6μm）同时用三种反义探针和相应的正义探针进行处理，证明了杂交信号的高特异性。结果表明，sGAP和sbGAP mRNA在嗅球、腹侧端脑和视前区有更广泛的表达，而cIIGAP mRNA表达局限于内侧纵束核的大细胞。在嗅球中，sGAP探针的信号强度和阳性细胞数量更高，而在视前区，表达sbGAP mRNA的细胞更多且染色更强烈。在腹外侧下丘脑还检测到额外的孤立sbGAP阳性细胞。这些结果表明，欧洲海鲈前脑中表达sGAP和sbGAP的细胞明显重叠，这与之前在其他鲈形目鱼类中的报道不同，之前的报道显示这两种细胞群明显分离。
