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Abstract:
Naris occlusion is the method of choice for investigating the effects of odor deprivation in mammals. However, unilateral closure of a naris causes marked changes in the airflow in both the occluded and open nasal cavity. While on the occluded side the airflow is dramatically reduced, the open side is forced to carry a larger than normal volume. Also, naris occlusion abrogates alternating cycles of breathing, forcing constant duty on the open side. We were
interested if these changes in airflow effect development of nasal turbinates given that mechanical stress induces bone growth and turbinates express odorant receptors in regionally defined areas. We therefore investigated mice aged 18-25 days, that had been naris occluded or shame operated on the day of birth. Turbinate morphology was examined in coronal serial sections throughout the
rostrocaudal extent of the nasal cavity. Results demonstrate that naris occlusion has signficant effects on the size, shape, and position of nasal turbinates, especially rostrally. The most anterior turbinate, endoturbinate-I, takes on a delicate “filigree” appearance on the occluded side relative to the open side: 24% decrease in
area/perimeter (open 65.2, closed 52.6; control 59.5 sq μm/μm; p<0.005) despite same perimeter; 82% increase in length/width, (open 7.4; closed 13.5; control 7.9 μm/μm; p <0.001). That these effects are attributed to airflow is supported by the intermediate values of controls. We conclude that a stimulus from airflow: mechanical, thermal or chemical, causes changes in the ontogenesis of nasal turbinate structure which in turn might induce changes in
expression of odorant receptors. Acknowledgements: This study was supported by National Science Foundation grant #0641433 to DC.
