TY - JOUR T1 - The Monoaminergic Modulation of Sensory-Mediated Aversive Responses in <em>Caenorhabditis elegans</em> Requires Glutamatergic/Peptidergic Cotransmission JF - The Journal of Neuroscience JO - J. Neurosci. SP - 7889 LP - 7899 DO - 10.1523/JNEUROSCI.0497-10.2010 VL - 30 IS - 23 AU - Gareth Harris AU - Holly Mills AU - Rachel Wragg AU - Vera Hapiak AU - Michelle Castelletto AU - Amanda Korchnak AU - Richard W. Komuniecki Y1 - 2010/06/09 UR - http://www.jneurosci.org/content/30/23/7889.abstract N2 - Monoamines and neuropeptides interact to modulate behavioral plasticity in both vertebrates and invertebrates. In Caenorhabditis elegans behavioral state or “mood” is dependent on food availability and is translated by both monoaminergic and peptidergic signaling in the fine-tuning of most behaviors. In the present study, we have examined the interaction of monoamines and peptides on C. elegans aversive behavior mediated by a pair of polymodal, nociceptive, ASH sensory neurons. Food or serotonin sensitize the ASHs and stimulate aversive responses through a pathway requiring the release of nlp-3-encoded neuropeptides from the ASHs. Peptides encoded by nlp-3 appear to stimulate ASH-mediated aversive behavior through the neuropeptide receptor-17 (NPR-17) receptor. nlp-3- and npr-17-null animals exhibit identical phenotypes and animals overexpressing either nlp-3 or npr-17 exhibit elevated aversive responses off food that are absent when nlp-3 or npr-17 are overexpressed in npr-17- or nlp-3-null animals, respectively. ASH-mediated aversive responses are increased by activating either Gαq or Gαs in the ASHs, with Gαs signaling specifically stimulating the release of nlp-3-encoded peptides. In contrast, octopamine appears to inhibit 5-HT stimulation by activating Gαo signaling in the ASHs that, in turn, inhibits both Gαs and Gαq signaling and the release of nlp-3-encoded peptides. These results demonstrate that serotonin and octopamine reversibly modulate the activity of the ASHs, and highlight the utility of the C. elegans model for defining interactions between monoamines and peptides in individual neurons of complex sensory-mediated circuits. ER -