Decoding of Polymodal Sensory Stimuli by Postsynaptic Glutamate Receptors in C. elegans

The C. elegans polymodal ASH sensory neurons detect mechanical, osmotic, and chemical stimuli and release glutamate to signal avoidance responses. To investigate the mechanisms of this polymodal signaling, we have characterized the role of postsynaptic glutamate receptors in mediating the response to these distinct stimuli. By studying the behavioral and electrophysiological properties of worms defective for non-NMDA (GLR-1 and GLR-2) and NMDA (NMR-1) receptor subunits, we show that while the osmotic avoidance response requires both NMDA and non-NMDA receptors, the response to mechanical stimuli only requires non-NMDA receptors. Furthermore, analysis of the EGL-3 proprotein convertase provides additional evidence that polymodal signaling in C. elegans occurs via the differential activation of postsynaptic glutamate receptor subtypes.