Development of the diencephalon in the rat. II. Correlation of the embryonic development of the hypothalamus with the time of origin of its neurons

Abstract

The development of the nuclei of the hypothalamus was examined in normal and X-irradiated embryos from day 13 (E13) to the day before birth (E22). The diencephalic neuroepithelium was subdivided into three lobes (dorsal, medial, and ventral) and two lobules (superior and inferior). The hypothalamus is derived from the ventral lobe and the inferior lobule. The ventral neuroepithelial lobe generates the neurons of most of the early arising hypothalamic structures, including those of the lateral tier nuclei associated with the medial forebrain bundle, and the heterogeneous intermediate tier nuclei. A specialized neuroepithelial region lining the diamond shaped ventricle produces the early neurohypophysial magnocellular neurons; the neurons of the paraventricular nucleus remain at this site, whereas the neurons of the supraoptic nucleus could be traced migrating laterally. The neurons of the late arising hypophysiotropic area of the posterior hypothalamus are derived from components of the inferior neuroepithelial lobule: the dorsomedial and ventromedial nuclei apparently from a shared matrix in the main portion of the inferior lobule; the tuberomammillary-arcuate complex from its posteroventral recess. The triple-decked and sequentially produced components of the mammillary system may arise from separate neuroepithelial sites. The autoradiographic results of the previous study (Altman and Bayer, '78a) showed that the structural and functional heterogeneity of the mature hypothalamus is paralleled by cytogenetic heterochronicity; the present embryonic observations indicate that many of the distinguishable components of the hypothalamus arise from a mosaic of heterogeneous neuroepithelial sites.

Directed differentiation of neural cells to hypothalamic dopaminergic neurons

“…In rodents, A12 tubero-infundibular dopaminergic (DA) neurons arise from the ventral lobe of the tuberal hypothalamus (Altman and Bayer 1978;Daikoku et al, 1986). Similarly, we find that tyrosine hydroxylase (Th)-immunoreactive neurons appear in the lateral tuberal hypothalamus at embryonic day 5 (E5) ( Fig.…”

Birthdate of parvalbumin-neurons in the Parvafox-nucleus of the lateral hypothalamus

“…Foxb1 is a winged helix transcription factor involved in the development of the diencephalon during the embryogenesis and to a lesser extent during the postnatal development (Altman and Bayer, 1978;Alvarez-Bolado et al, 2000;Croizier et al, 2014;Iball et al, 1966;Markakis and Swanson, 1997;Szabo et al, 2015). Foxb1 is expressed in a "patch" of the caudal hypothalamic neuroepithelium that gives rise to neurons later forming defined hypothalamic nuclei.…”

“…Indeed, the melanin-concentrating hormone (MCH) producing neurons, which form an abundant cell population widespread in the diencephalon and also present in the lateral hypothalamus show a similar spatio-temporal ontogeny also peaking between E12 and E13 (although the MCH-expressing neurons are generated throughout the entire time-period of genesis of the whole hypothalamus, i.e. E10-E17) (Altman and Bayer, 1978;Altman and Bayer, 1986;Amiot et al, 2005;Brischoux et al, 2001;Khachaturian et al, 1985). The hypocretin/orexin positive neurons in the lateral hypothalamus, which are involved in the regulation of sleep/waking states (Chemelli et al, 1999;Nishino et al, 2000;Peyron et al, 2000;Thannickal et al, 2000) and feeding behavior (Qu et al, 1996;Rossi et al, 1997), display also a similar ontogenic pattern.…”

Spatiotemporal patterns of secretomotor neuron generation in the parvicellular neuroendocrine system 1Published on the World Wide Web on 3 June 1997. 1

“…Curiously, such neurons in both the supraoptic nucleus, which in the adult lies along the surface of the brain, and the PVH, which remains adjacent to the neuroepithelium, are born at the same time, with a peak on e13 ( [26], present results). Magnocellular neurosecretory neurons in both nuclei appear to be generated from the same patch of dorsal third ventricular neuroepithelium, and some of them migrate radially through the mantle layer over the course of perhaps 2 or 3 days to the surface of the neural tube to form the supraoptic nucleus [2][3][4].…”