Analysis of the functional maturation of olfactory neurons in chicks before and after birth.
There has been indirect evidence that the olfactory system of mammals could be functional shortly before birth. Taking advantage of the accessibility of bird embryos, we studied the functional maturation of the olfactory mucosa during embryonic development in birds. Using the combination of electrophysiological EOG recordings and immunohistochemical studies, it was possible to directly demonstrate for the first time that the olfactory system is functional during embryogenesis from embryonic day (ED) 13 and that the beginning of olfactory function coincides with the first localization of the calcium dependent calmodulin kinase II (CaMKIIalpha) in the dendrites of the olfactory receptor neurons. CaMKII and olfactory receptor genes are expressed much earlier in olfactory neurons, both involved in the sensory transduction, but the pattern of expression of CaMKIIalpha changes during the ontogenesis. The increase of EOG amplitude between ED13 and ED15 also coincides with the increase of the number of neurons presenting the dendritic localization of CaMKIIalpha. These results suggest that the enzyme CaMKII might play a role in the functional maturation of the olfactory mucosa.
Lalloué
Fabrice L
FL
UMR CNRS 6101, Faculté de Médecine, 2 rue du Dr Marcland 87025 Limoges, France.
Ayer-Le Lièvre
Christiane S
CS
Sicard
Gilles
G
D000375:Aging / Q000502:physiology; D000818:Animals; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002645:Chickens; D004594:Electrophysiology; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D009830:Olfactory Bulb / Q000187:drug effects / Q000196:embryology* / Q000254:growth & development* / Q000378:metabolism; D018034:Olfactory Receptor Neurons / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D013268:Stimulation, Chemical
D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases