Odors regulate Arc expression in neuronal ensembles engaged in odor processing

Synaptic activity is critical to developmental and plastic processes that produce long-term changes in neuronal connectivity and function. Genes expressed by neurons in an activity-dependent fashion are of particular interest since the proteins they encode may mediate neuronal plasticity. One such gene encodes the activity-regulated cytoskeleton-associated protein, Are. The present study evaluated the effects of odor stimulation on Are expression in rat olfactory bulb. Are mRNA was rapidly increased in functionally linked cohorts of neurons topographically activated by odor stimuli. These included neurons surrounding individual glomeruli, mitral cells and transynaptically activated granule cells. Dendritic Are immunoreactivity was also increased in odor-activated glomeruli. Our results suggest that odor regulation of Are expression may contribute to activity-dependent structural changes associated with olfactory experience. NeuroReport 11:1809-1813 (C) 2000 Lippincott Williams & Wilkins.