Olfactory placode

Fig. 4.1 Differentiation of olfactory placode (O). Rostral CNS in vertebrates Fb = forebrain (from Graham and Begbie, 2000).

Fig. 4.2 Differentiation from olfactory placode of main and VN primordia (a) to (b), embryonic stages in reptiles (Squamates and Crocodylia). (a), Early invagination of placode (a ), late separation of primordia for AOS/MOS and (b), agenesis of presumptive VN(JO) cells in crocodile (NPT, nasal pit) (from Parsons, 1970).

Fig. 4.3 Morphogenesis during metamorphosis in Amphibia diagramatic sequence of MOS/AOS formation in African Clawed Toad (Xenopus). OP, olfactory placode PC, principal cavity and MC, mid-cavity (from Meyer and Jadhao, 1996).

Daikoku S., Koide I., Chikamoriaoyama M. and Shimomura Y. (1993). Migration of LHRH neurons derived from the olfactory placode in rats. Arch Histol Cytol 56, 353-370. 

Key S. and Wray S. (2000). Two olfactory placode derived galanin subpopulations luteinizing hormone-releasing hormone neurones and vomeronasal cells. J Neuroendocrinal 12, 535—545. 

Murakami S. and Arai Y. (1992). Origin of LHRH-neurons in Newts effect of olfactory placode ablation. Cell liss Res 269, 21-27. 

Wray S Grant P. and Gainer H. (1989). Evidence that cells expressing LHRH-mRNA in the mouse are derived from progenitor cells in the olfactory placode. Proc Natl Acad Sci 86, 8132-8136. 

Otxl is also expressed at early stages in precursor structures of sense organs corresponding to the olfactory placode, otic and optic vescicles (Simeone et al., 1993). Later on, Otxl is transcribed in the olfactory epithelium, the saccule, the cochlea, and the lateral semicircular canal of the inner ear as well as in the iris, the ciliary process in the eye and the lachrymal gland primordia (Simeone et al., 1993). From the birthday onwards, Otxl is also expressed at a relatively low level in the anterior lobe of the pituitary gland (Acampora et al., 1998c). 

Bums CJ, Vetter ML. Xath5 regulates neurogenesis in the Xenopus olfactory placode. Dev Dyn. 2002 225 536-43. 

G. gallus since El PSM, somites, at E2.1 telencephalon, olfactory placodes at 7.5 Mullerian duct Smith et al., 2002... 

X. laeois since stage 17, olfactory placodes, forebrain, telencephalon Huang et al, 2005b... 

X. maculatus since day 3, olfactory placodes day 5 olfactory placodeS/ branchial arches, B G Veith et al., 2006a... 

The direct link between the nose and the reproductive system has been called a non-cognitive bridge (Stoddart, 1990). A part of VN projection is non-olfactory and reaches the limbic system via a direct and monosynaptic relay (Larriva-Sahd et al., 1993 and 1994 Matsumoto et al., 1994). In addition to the production of the peripheral olfactory cells (Sec. 4.1 above), the placode also gives rise to a group of important... 

Miyasaka N, Knaut H, Yoshihara Y (2007) Cxcll2/Cxcr4 chemokine signaling is required for placode assembly and sensory axon pathfinding in the zebrafish olfactory system. Development... 

---