Odorants stimulate the ERK/mitogen-activated protein kinase pathway and activate cAMP-response element-mediated transcription in olfactory sensory neurons

Olfactory sensory neurons (OSNs) respond acutely to volatile molecules and exhibit adaptive responses including desensitization to odorant exposure. A lthough mechanisms for short term adaptation have been described, there is little evidence that odorants cause long lasting, transcription-dependent c hanges in OSNs. Here we report that odorants stimulate cAMP-response elemen t (CRE)-mediated transcription in OSNs through Ca2+ activation of the ERK/M APK/p90(rsh) pathway, Odorant stimulation of ERK phosphorylation was ablate d by inhibition of calmodulin-dependent protein kinase II suggesting that o dorant activation of ERK is mediated through this kinase. Moreover, a brief exposure in vivo to an odorant in vapor phase stimulated CRE-mediated gene transcription in discrete populations of OSNs. These data suggest that lik e central nervous system neurons, OSNs may undergo long term adaptive chang es mediated through CRE-mediated transcription.