Unilateral olfactory deprivation: effects on succinate dehydrogenase histochemistry and [³H]leucine incorporation in the olfactory mucosa

Surgically closing one external naris reduces airflow through one half of the nasal cavity, decreasing the access of odors to the receptor sheet. In rats, unilateral naris occlusion performed near birth results in large reductions in the size of the olfactory bulb, the primary central relay, when examined 30 days later. Previous research has demonstrated that there is a rapid reduction in [ ³H]2-deoxyglucose (2-DG) and [³H]leucine uptake in the bulb within hours after naris closure. The present study examined whether similar rapid changes could be observed in the sensory periphery. Pups occluded on P1 and examined on P3 with succinate dehydrogenase histochemistry exhibited reduced staining on the closed side of the nasal cavity, suggesting occlusion results in reductions in mucosal metabolism. Larger differences in staining were observed in pups examined at P6. [³H]Leucine incorporation was quite similar on both sides of the nasal septum as late as 30 days post occlusion, suggesting less dramatic changes in protein synthesis. The results suggest that naris closure docs indeed have rapid effects on mucosal function, but indicate that the changes are different than those observed in the bulb.