Can anyone point me in the direction of any publication that definitively shows that the hypothalamus does not share a developmental origin with the olfactory system, adjacent to the olfactory placodes and anterior pituitary? De Beer's classic 1924 paper has the relationship quite clear.
If the hypothalamus does not originate close to the adenohypophysis and olfactory system is there any doubt about its ectodermal origin?
may be thses references could help?
Puelles and Rubenstein, 1993, 2003; Puelles, 1995, 2001; Puelles et al., 2011
Best
According to the Langman´s medical embryology is the hypothalamus developed from the basal plate of the diencephalon and the anterior pituitary from the Rathke´s pouch of the ectoderm of the primitive stomodeum. The olfactory placodes are developed from the ectoderm. They are located on either side of the frontonasal prominence of the developing face. Their development is influenced from the telencephalon (rhinencephalon on the rostrobasal part of the hemospheres - olfactory bulb).
Be carefull olfactory placode may have a dual origin (ectoderm and neural crest)
Whitlock KE, Wolf CD, Boyce ML. 2003. Gonadotropin-releasing hormone (GnRH) cells arise from cranial neural crest and adenohypophyseal regions of the neural plate in the zebrafish, Danio rerio. Dev Biol 257:140–152.
the classic papers by Altman and Bayer had components for migration and origin based on where the cells were as they leave the mitotic cycle. Most of the hypothalamus develops from the nearby 3rd ventricular stratum. The first neurons to develop within the hypothalamus end up lateral and ventral to the median eminence for the mediobasal groups. There are, however some neurons that do develop from the olfactory placode (the GnRH neurons) and it is thought that some cells that contain olfactory marker protein also come in from the olfactory system. The former are well described (see Wray and Schwanzel-Fukuda). There is a small bit of data suggesting that some do come in from below in the adenohypophysis, but that route is likely minimal in most animals. The GnRH system travels with the axons of the olfactory neurons and so you will not find a contradiction of that path. While the Whitlock papers suggest an neural crest origin, studies by Wray support a placode origin.
may be this more recent review will help you:
Machluf Y, Gutnick A, Levkowitz G. Development of the zebrafish hypothalamus. Trends in Neuroendocrinology, 2011: 93-105.
Or try to contact the Levkowitz group directly.
regards
I just noticed that the populations of cells that give rise to the GnRH system are mixed between the ectodermal and neural crest. Neural crest and ectodermal cells intermix in the nasal placode to give rise to GnRH-1 neurons, sensory neurons, and olfactory ensheathing cells.
Forni PE, Taylor-Burds C, Melvin VS, Williams T, Wray S.
J Neurosci. 2011 May 4;31(18):6915-27. doi: 10.1523/JNEUROSCI.6087-10.2011. Erratum in: J Neurosci. 2011 Sep 7;31(36):13023. Williams, Taylor [corrected to Williams, Trevor].
PMID:
21543621
[PubMed - indexed for MEDLINE]
Free PMC Article
The complete reference for Altman and Bayer is a book chaper.
The development of the rat hypothalamus, altman and bayer, springer verlag 1986
All the last informations about this questions point to the signed up for Veronika Nemcova according to the Larsen's Human Embriology, third edition (2003), Moore's Human Embriology and Biology of Development, fourth edition (2009) and Langman's Medical Embriology 12 edition ( 2012).
There are a number of recent reviews that likely have more of the recent data than a textbook. In my experience, texts can be years behind the literature and 2009 and 2003 would have little of the new information.
De Beers was very actual in the begining of the last century (almost 100 years ago) - concepts had changed a lot , meantime.. Langman is not the best Embryology - it is notorious it refers at chick not mmmals. Hypothalamus is obviously neuroectodermal, anyhow. cells from olfactory placode seem to travel to it. See Gray's 1998 (not 2005!) etc etc it's long story
An excellent paper by G Alvarez-Bolado, Neural Devel. 7, 2012 indicates that neural progenitors of the hypothalamus seem to arise from an area continuous with the ventral midbrain. Progenitors of hypothalamus neurons become organized into three main divisions, plus an anterior division, that are basically analogous to the neuromeres of more posterior structures. This article is available for free at the webiste www.pubmed.gov. Also, the conclusion that the hypothalamus develops from 3-4 discrete divisions is in accord with my own 3 dimensional reconstruction of the rat hypothalamus that shows 3 distinct divisions of the adult structure.
John Young
Department of Anatomy
Howard University
Back in the 1940's, French investigators Couly and Le Douarin used quail-chick graft experiments to map the fate of different areas of the neuroectoderm and anterior ridge. Is doesn't help much for the molecular aspects of the question but these experiments are still regarded as demonstrative pioneering work in the field. Their approach was quite circumspect so there olfactory areas must have been studied as well, I'll let you have a look for yourself.
Couly GF, Le Douarin NM 1985 Mapping of the early neural primordium in quail-chick chimeras. I. Developmental relationships between placodes, facial ectoderm, and prosencephalon. Dev Biol 110:422-439
In most species, the hypothalamus forms from the neural ectoderm as a part of the diencephalon. There is. however some noteworthy exceptions: The neurons that reside in the hypothalamus which are responsible for regulating the pituitary gonadotrophs arise from the olfactory placode and migrate into the hypothalamus along side the olfactory nerves. These gonadotropin releasing hormone neurons are accompanyied by a heterogeneous group of cells in the rostral migratory stream that also end up in the hypothalamus. Work by Dr. Susan Wray at the NIH , Dr. Marlene Swanzel-Fukuda, and Dr.. Frank Margolis have studied these unusual cells and described their path of entry into the CNS many years ago (early 90's). Other investigators have shown that in some non-mammalian systems cells of the neural crest can enter the brain to add to the GnRH system. In addition, "foreign" residents of the Central nervous system include the mesencephalic V nucleus in the brainstem. It too entered the CNS from outside during fetal development.