Development of three distinct GnRH neuron populations expressing two different GnRH forms in the brain of the African catfish (Clarias gariepinus)
| Autor: | Jan Bogerd, Eline A. Dubois, Henk J.Th. Goos, Jan Peute, M.A. Zandbergen |
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| Rok vydání: | 2001 |
| Předmět: |
Male
Aging endocrine system medicine.medical_specialty Population Biology Gonadotropin-Releasing Hormone Midbrain Antibody Specificity Internal medicine Neural Pathways medicine Animals Protein Isoforms education Catfishes Phylogeny Fluorescent Dyes Neurons GnRH Neuron education.field_of_study General Neuroscience Brain Carbocyanines Preoptic area medicine.anatomical_structure Endocrinology nervous system Hypothalamus Forebrain Terminal nerve hormones hormone substitutes and hormone antagonists Catfish |
| Zdroj: | The Journal of Comparative Neurology. 437:308-320 |
| ISSN: | 1096-9861 0021-9967 |
| DOI: | 10.1002/cne.1285 |
| Popis: | The early development of both the catfish gonadotropin-releasing hormone (cfGnRH)- and the chicken GnRH-II (cGnRH-II) system was investigated in African catfish by immunocytochemistry by using antibodies against the GnRH-associated peptide (GAP) of the respective preprohormones. Weakly cfGnRH-immunoreactive (ir) neurons and fibers were present at 2 weeks after hatching (ph) but only in the ventral telencephalon and pituitary. Two weeks later, cfGnRH fibers and neurons were also observed in more rostral and in more caudal brain areas, mainly in the preoptic area and hypothalamus. Based on differences in temporal, spatial, and morphologic appearance, two distinct cfGnRH populations were identified in the ventral forebrain: a population innervating the pituitary (ventral forebrain system) and a so-called terminal nerve (TN) population. DiI tracing studies revealed that the TN population has no neuronal connections with the pituitary. The cGnRH-II system is present from 2 weeks ph onward in the midbrain tegmentum and only their size and staining intensity increased during development. Based on the comparison of GnRH systems amongst vertebrates, we hypothesize that during fish evolution, three different GnRH systems evolved, each expressing their own molecular form: the cGnRH-II system in the midbrain, a hypophysiotropic GnRH system in the hypothalamus with a species-specific GnRH form, and a salmon GnRH-expressing TN population. This hypothesis is supported by phylogenetic analysis of known GnRH precursor amino acid sequences. We hypothesize, because the African catfish is a less advanced teleost species, that it contains the cfGnRH form both in the ventral forebrain system and in the TN population.J. Comp. Neurol. 437:308–320, 2001. © 2001 Wiley-Liss, Inc. |
| Databáze: | OpenAIRE |
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