OLFACTORY EXPERIENCE MODULATES APOPTOSIS IN THE DEVELOPING OLFACTORY-BULB

Early sensory stimulation plays a key role in shaping the structure an d function of the developing olfactory system. Here, we provide the fi rst direct evidence for apoptotic cell death in the olfactory bulbs of rat pups during normal development and we also demonstrate that olfac tory deprivation by unilateral naris occlusion causes a dramatic incre ase in apoptotic cell death in the glomerular and granule cell layers of the deprived bulb. The accessory olfactory bulbs displayed a remark ably high basal level of apoptosis but the occluded accessory bulb did not differ in that regard from the control accessory bulb. These resu lts suggest that apoptosis may be an important mechanism by which the olfactory system can adjust its cell numbers in response to sensory st imuli experienced in early life, thereby underlying one form of plasti city in the developing olfactory system.