Molecular Strategies for Intensity-Dependent Olfactory Processing in Caenorhabditis elegans

Various odorants trigger complex animal behaviors across species in both quality- and quantity-dependent manners. However, how the intensity of olfactory input is encoded remains largely unknown. Here we report that isoamyl alcohol (IAA) induces bi-directional currents through a G alpha- guanylate cyclase (GC)- cGMP signaling pathway in Caenorhabditis elegans olfactory neuron amphid wing C cell (AWC), while two opposite cGMP signaling pathways are responsible for odor-sensing in olfactory neuron amphid wing B cell (AWB): (1) a depolarizing G alpha (GPA-3)- phosphodiesterase (PDE) - cGMP pathway which can be activated by low concentrations of isoamyl alcohol (IAA), and (2) a hyperpolarizing G alpha (ODR-3)- GC- cGMP pathway sensing high concentrations of IAA. Besides, IAA induces G alpha (ODR-3)-TRPV(OSM-9)-dependent currents in amphid wing A cell (AWA) and amphid neuron H cell with single ciliated sensory ending (ASH) neurons with different thresholds. Our results demonstrate that an elaborate combination of multiple signaling machineries encode the intensity of olfactory input, shedding light on understanding the molecular strategies on sensory transduction.

Automated summary

This study reveals that different odorants can trigger complex behaviors in Caenorhabditis elegans through multiple signaling pathways, encoding the intensity of olfactory input. Understanding the molecular strategies involved in sensory transduction is essential for decoding the mechanisms underlying animal behaviors.