Hypothalamic neurosecretory and circadian vasopressinergic neuronal systems in the blind cone-rod homeobox knock out mouse (Crx(-/-) ) and the 129sv wild type mouse
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Vasopressin (AVP) is both a neuroendocrine hormone located in magnocellular neurosecretory neurons of the hypothalamus of mammals but also a neurotransmitter/neuromodulator in the parvocellular suprachiasmatic nucleus (SCN). The SCN is the endogenous clock of the brain and exhibits a prominent circadian AVP-rhythm. We have in this study of the brown 129sv mouse and the visual blind cone-rod homeobox gene knock out mouse (Crx(-/-) ) with degeneration of the retinal rods and cones, but a preserved non-image forming optic system, studied the temporal Avp-expression in both the neurosecretory magnocellular and parvocellular vasopressinergic systems in both genotypes. We here present a detailed mapping of all classical hypothalamo-pituitary and accessory magnocellular nuclei and neurons in the hypothalamus by use of immunohistochemistry and in situ hybridization in both genotypes. Semiquantitative in situ hybridization revealed a very high expression of Avp-mRNA in all the magnocellular nuclei compared to a much lower level in the parvocellular suprachiasmatic nucleus. In a series of mice killed every 4 hours, The Avp-mRNA expression in the SCN showed a significant daily rhythm with a zenith at late day time and nadir during the dark in both the Crx(-/-) and the wild type mouse. None of the magnocellular neurosecretory neurons exhibited a diurnal vasopressin expression. Light stimulation of both genotypes during the dark period did not change the Avp-expression in the SCN. This shows that Avp-expression in the mouse SCN is independent of Crx-regulated photoreceptor systems. J. Comp. Neurol., 2013. © 2013 Wiley Periodicals, Inc.
Original language | English |
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Journal | Journal of Comparative Neurology |
Volume | 521 |
Issue number | 17 |
Pages (from-to) | 4061-4074 |
Number of pages | 14 |
ISSN | 0021-9967 |
DOIs | |
Publication status | Published - 20 Jun 2013 |
ID: 47565736