The C-elegans glutamate receptor subunit NMR-1 is required for slow NMDA-activated currents that regulate reversal frequency during locomotion

The N-methyl-D-aspartate (NMDA) subtype of glutamate receptor is important for synaptic plasticity and nervous system development and function. We hav e used genetic and electrophysiological methods to demonstrate that NMR-1, a Caenorhabditis elegans NMDA-type ionotropic glutamate receptor subunit, p lays a role in the control of movement and foraging behavior. nmr-1 mutants show a lower probability of switching from forward to backward movement an d a reduced ability to navigate a complex environment. Electrical recording s from the interneuron AVA show that NMDA-dependent currents are selectivel y disrupted in nmr-1 mutants. We also show that a slowly desensitizing vari ant of a non-NMDA receptor can rescue the nmr-1 mutant phenotype. We propos e that NMDA receptors in C. elegans provide long-lived currents that modula te the frequency of movement reversals during foraging behavior.