title: Architecture of the hypothalamo-posthypophyseal complex is controlled by monoamines.
abstract: The hypothalamo-neurohypophyseal system displays significant plasticity when subjected to physiological stimuli, such as dehydration, parturition, or lactation. This plasticity arises at the neurochemical and electrophysiological levels but also at a structural level. Several studies have demonstrated the role of monoaminergic afferents in controlling neurochemical and electrophysiological plasticity of the supraoptic nucleus (SON) and of the neurohypophysis (NH), but little is known about how the changes in structural plasticity are triggered. We used Tg8 mice, disrupted for the monoamine oxidase A gene, to study monamine involvement in the architecture of the SON and of the NH. SON astrocytes in Tg8 mice displayed an active status, characterized by an increase in S100β expression and a significant decrease in vimentin expression, with no modification in glial fibrillary acidic protein (GFAP) levels. Astrocytes showed a decrease in glutamate dehydrogenase (GDH) levels, whereas glutamine synthetase (GS) levels remained constant, suggesting a reduction in astrocyte glutamate catabolism. Tenascin C and polysialic acid-neural cell adhesion molecule (PSA-NCAM) expressions were also elevated in the SON of Tg8 mice, suggesting an increased capacity for structural remodelling in the SON. In the NH, similar date were obtained with a stability in GFAP expression and an increase in PSA-NCAM immunostaining. These results establish monoamine (serotonin and noradrenaline) involvement in SON and NH structural arrangement. Monoamines therefore appear to be crucial for the coordination of the neurochemical and structural aspects of neuroendocrine plasticity, allowing the hypothalamo-neurohypopyseal system to respond appropriately when stimulated.
authors.affiliation: Laboratoire de Neuroendocrinologie Moléculaire de la Prise Alimentaire, Centre de Neurosciences Paris-Sud, UMR 8195, Université Paris-Sud, CNRS Orsay, France.
authors.forename: Claire-Marie
authors.initials: CM
authors.lastname: Vacher
authors.forename: Valérie
authors.initials: V
authors.lastname: Grange-Messent
authors.forename: Ronald
authors.initials: R
authors.lastname: St-Louis
authors.forename: Danièle
authors.initials: D
authors.lastname: Raison
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Lacorte
authors.forename: Hélène
authors.initials: H
authors.lastname: Hardin-Pouzet
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000166:cytology* / Q000378:metabolism; D048430:Cell Shape; D005904:Glial Fibrillary Acidic Protein; D007031:Hypothalamus / Q000166:cytology* / Q000378:metabolism; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008995:Monoamine Oxidase / Q000235:genetics / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D019006:Neural Cell Adhesion Molecules / Q000378:metabolism; D009473:Neuronal Plasticity / Q000502:physiology; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D010904:Pituitary Gland, Posterior / Q000166:cytology* / Q000378:metabolism; D014746:Vimentin / Q000378:metabolism
chemical_list: D005904:Glial Fibrillary Acidic Protein; D009419:Nerve Tissue Proteins; D019006:Neural Cell Adhesion Molecules; D014746:Vimentin; C528900:glial fibrillary astrocytic protein, mouse; D008995:Monoamine Oxidase