Neuroanatomical characterization of the kisspeptin systems in the brain of european sea bass (D. labrax)

Trabajo presentado en el 25th Conference of European Comparative Endocrinologists, celebrada en Pécs (Hungría), del 31 de agosto al 4 de septiembre de 2010Kisspeptins are a family of peptides encoded by the KISS1 gene, in mammals, and kiss1 and kiss2 in fish. They were first identified by their capacity to inhibit tumor metastasis through the receptor GPR54, also termed KISSR. Nowadays, it is largely demonstrated that the kiss system plays an essential role in the neuroendocrine control of puberty and reproduction in several mammalian species, stimulating GnRH secretion at the hypothalamus. In the sea bass, an economically-important marine teleost, kiss1 and kiss2 coding sequences and those of their cognate receptors have been recently identified. Thus, this is the first study aimed to elucidate the neuroanatomical distribution of the cells expressing the two kiss genes and their receptors in adult sea bass brain by in situ hybridization. Our findings indicate the mediobasal hypothalamus, notably the nucleus of the lateral recess, as an important area of expression of both kiss1 and kiss2 genes. Furthermore, the kiss1expressing cells are also located at the level of the habenular region. Interestingly, the kisspeptin receptors-expressing cells are mostly placed in the same regions as the corresponding ligands. These results are in line with those obtained in the other fish species investigated so far. In conclusion, this work represents the first neuroanatomical analysis of the kisspeptin systems in the sea bass brain and suggests a putative involvement of the kisspeptins in the control of reproduction in this species.Supported by the EU Project LIFECYCLE (FP7-222719-1). Sebastián Escobar was sponsored by JAE-Predoc CSIC. Spain