Properties, projections, and tuning of teleost olfactory receptor neurons

In many fishes, the olfactory sense participates in such vital processes as feeding, reproduction, orientation, and predator avoidance. In teleosts, these tasks are fulfilled by a single type of olfactory organ for odorant and pheromone detection, containing ciliated and microvillus receptor neurons, and olfactory crypt cells. Recently, progress was made in understanding crypt cell function with the discovery of a V1R-like odorant receptor expressed in this neuron, an analysis of crypt cell odorant tuning properties, and the dissection of crypt cell connectivity within the telecephalon. Here, we review recent findings on the molecular properties, functions, and associated neural pathways of the three types of teleost olfactory receptor neurons with special emphasis on the crypt cell, and evaluate their roles in the detection of food, social and sexual odorants.