TY - JOUR
T1 - Distinct mechanisms underlie quiescence during two Caenorhabditis elegans sleep-like states
AU - Trojanowski, Nicholas F.
AU - Nelson, Matthew D.
AU - Flavell, Steven W.
AU - Fang-Yen, Christopher
AU - Raizen, David M.
PY - 2015/10/28
Y1 - 2015/10/28
N2 - Electrophysiological recordings have enabled identification of physiologically distinct yet behaviorally similar states of mammalian sleep. In contrast, sleep in nonmammals has generally been identified behaviorally and therefore regarded as a physiologically uniform state characterized by quiescence of feeding and locomotion, reduced responsiveness, and rapid reversibility. The nematode Caenorhabditis elegans displays sleep-like quiescent behavior under two conditions: developmentally timed quiescence (DTQ) occurs during larval transitions, and stress-induced quiescence (SIQ) occurs in response to exposure to cellular stressors. Behaviorally, DTQ and SIQ appear identical. Here, we use optogenetic manipulations of neuronal and muscular activity, pharmacology, and genetic perturbations to uncover circuit and molecular mechanisms of DTQ and SIQ. We find that locomotion quiescence induced by DTQ-and SIQ-associated neuropeptides occurs via their action on the nervous system, although their neuronal target(s) and/or molecular mechanisms likely differ. Feeding quiescence during DTQ results from a loss of pharyngeal muscle excitability, whereas feeding quiescence during SIQ results from a loss of excitability in the nervous system. Together these results indicate that, as in mammals, quiescence is subserved by different mechanisms during distinct sleep-like states in C. elegans.
AB - Electrophysiological recordings have enabled identification of physiologically distinct yet behaviorally similar states of mammalian sleep. In contrast, sleep in nonmammals has generally been identified behaviorally and therefore regarded as a physiologically uniform state characterized by quiescence of feeding and locomotion, reduced responsiveness, and rapid reversibility. The nematode Caenorhabditis elegans displays sleep-like quiescent behavior under two conditions: developmentally timed quiescence (DTQ) occurs during larval transitions, and stress-induced quiescence (SIQ) occurs in response to exposure to cellular stressors. Behaviorally, DTQ and SIQ appear identical. Here, we use optogenetic manipulations of neuronal and muscular activity, pharmacology, and genetic perturbations to uncover circuit and molecular mechanisms of DTQ and SIQ. We find that locomotion quiescence induced by DTQ-and SIQ-associated neuropeptides occurs via their action on the nervous system, although their neuronal target(s) and/or molecular mechanisms likely differ. Feeding quiescence during DTQ results from a loss of pharyngeal muscle excitability, whereas feeding quiescence during SIQ results from a loss of excitability in the nervous system. Together these results indicate that, as in mammals, quiescence is subserved by different mechanisms during distinct sleep-like states in C. elegans.
KW - C. elegans
KW - Invertebrate
KW - Neural circuit
KW - Optogenetics
KW - Sleep
UR - http://www.scopus.com/inward/record.url?scp=84945561571&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84945561571&partnerID=8YFLogxK
U2 - 10.1523/JNEUROSCI.1369-15.2015
DO - 10.1523/JNEUROSCI.1369-15.2015
M3 - Article
C2 - 26511247
AN - SCOPUS:84945561571
VL - 35
SP - 14571
EP - 14584
JO - Journal of Neuroscience
JF - Journal of Neuroscience
SN - 0270-6474
IS - 43
ER -