Postsynaptic ERG potassium channels limit muscle excitability to allow distinct egg-laying behavior states in caenorhabditis elegans

Kevin M. Collins, Michael R. Koelle

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

Caenorhabditis elegans regulates egg laying by alternating between an inactive phase and a serotonin-triggered active phase. We found that the conserved ERG [ether-a-go-go (EAG) related gene] potassium channel UNC-103 enables this two-state behavior by limiting excitability of the egg-laying muscles. Using both high-speed video recording and calcium imaging of egg-laying muscles in behaving animals, we found that the muscles appear to be excited at a particular phase of each locomotor body bend. During the inactive phase, this rhythmic excitation infrequently evokes calcium transients or contraction of the egg-laying muscles. During the serotonin-triggered active phase, however, these muscles are more excitable and each body bend is accompanied by a calcium transient that drives twitching or full contraction of the egg-laying muscles.Wefound that ERG-null mutants lay eggs too frequently, and that ERG function is necessary and sufficient in the egg-laying muscles to limit egg laying. ERG K+ channels localize to postsynaptic sites in the egg-laying muscle, and mutants lacking ERG have more frequent calcium transients and contractions of the egg-laying muscles even during the inactive phase. Thus ERG channels set postsynaptic excitability at a threshold so that further adjustments of excitability by serotonin generate two distinct behavioral states.

Original languageEnglish (US)
Pages (from-to)761-775
Number of pages15
JournalJournal of Neuroscience
Volume33
Issue number2
DOIs
StatePublished - Jan 9 2013

ASJC Scopus subject areas

  • Neuroscience(all)

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