Characterisation and origins of melanin-concentrating hormone immunoreactive fibres of the posterior lobe of the pituitary and median eminence during lactation in the Long-Evans rat.

Autor: Costa HC; Laboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil., Da-Silva JM; Laboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil., Diniz GB; Laboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil., Motta-Teixeira LC; Laboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil.; Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil., Da-Silva RJ; Laboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil., Battagello DS; Laboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil.; Center for Neuroscience and Behavior, Institute of Psychology, University of São Paulo (USP), São Paulo, Brazil., Sita LV; Laboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil., de-Moraes Machado C; Department of Anatomy, Institute of Biosciences, São Paulo State University (UNESP), Botucatu, Brazil., Horta-Júnior JAC; Department of Anatomy, Institute of Biosciences, São Paulo State University (UNESP), Botucatu, Brazil.; Electron Microscopy Center, Institute of Biosciences, São Paulo State University (UNESP), Botucatu, Brazil., Bittencourt JC; Laboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil.; Center for Neuroscience and Behavior, Institute of Psychology, University of São Paulo (USP), São Paulo, Brazil.
Jazyk: angličtina
Zdroj: Journal of neuroendocrinology [J Neuroendocrinol] 2019 Sep; Vol. 31 (9), pp. e12723. Date of Electronic Publication: 2019 May 23.
DOI: 10.1111/jne.12723
Abstrakt: Although the melanin-concentrating hormone (MCH) and its coding mRNA are predominantly found in the tuberal hypothalamus, there is detectable synthesis of MCH in the preoptic hypothalamus exclusively in lactating dams, suggesting a participation of MCH in the alterations that take place after parturition. Also implicated in the dam physiology is oxytocin, a neurohormone released from the posterior pituitary that is necessary for milk ejection. Because the projection fields from oxytocin-immunoreactive (-IR) neurones and the mediobasal preoptic hypothalamus overlap and MCH-IR neurones are found in proximity to oxytocin neurones, we investigated the spatial relationship between MCH and oxytocin fibres. Accordingly, we employed multiple immunohistochemistry labelling for MCH and oxytocin for light and electron microscopy techniques, in addition to i.v. tracer injection combined with in situ hybridisation to identify MCH neurones that project to neurosecretory areas. As described for other strains, lactating Long-Evans dams also display immunoreactivity for MCH in the preoptic hypothalamus on days 12 and 19 of lactation. The appearance of these neurones is contemporaneous with an increase in MCH-IR fibres in both the internal layer of the median eminence and the posterior pituitary. In both regions, MCH- and oxytocin-IR fibres were found in great proximity, although there was no evidence for synaptic interaction between these two populations at the ultrastructural level. The tracer injection revealed that only mediobasal preoptic MCH neurones project to the posterior pituitary, suggesting a neuroendocrine-modulatory role for this population. When taken together, the results obtained in the present study indicate that neuroplasticity events at the mediobasal preoptic hypothalamus that occur during late lactation may be part of a neuroendocrinology control loop involving both MCH and oxytocin.
(© 2019 British Society for Neuroendocrinology.)
Databáze: MEDLINE
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