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The GAR-3 muscarinic receptor cooperates with calcium signals to regulate muscle contraction in the Caenorhabditis elegans pharynx.

ABSTRACT: Muscarinic acetylcholine receptors regulate the activity of neurons and muscle cells through G-protein-coupled cascades. Here, we identify a pathway through which the GAR-3 muscarinic receptor regulates both membrane potential and excitation-contraction coupling in the Caenorhabditis elegans pharyngeal muscle. GAR-3 signaling is enhanced in worms overexpressing gar-3 or lacking GPB-2, a G-protein beta-subunit involved in RGS-mediated inhibition of G(o)alpha- and G(q)alpha-linked pathways. High levels of signaling through GAR-3 inhibit pharyngeal muscle relaxation and impair feeding--but do not block muscle repolarization--when worms are exposed to arecoline, a muscarinic agonist. Loss of gar-3 function results in shortened action potentials and brief muscle contractions in the pharyngeal terminal bulb. High levels of calcium entry through voltage-gated channels also impair terminal bulb relaxation and sensitize worms to the toxic effects of arecoline. Mutation of gar-3 reverses this sensitivity, suggesting that GAR-3 regulates calcium influx or calcium-dependent processes. Because the effects of GAR-3 signaling on membrane depolarization and muscle contraction can be separated, we conclude that GAR-3 regulates multiple calcium-dependent processes in the C. elegans pharyngeal muscle.

SUBMITTER: Steger KA

PROVIDER: S-EPMC1470925 | biostudies-other | 2004 Jun

REPOSITORIES: biostudies-other

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The GAR-3 muscarinic receptor cooperates with calcium signals to regulate muscle contraction in the Caenorhabditis elegans pharynx.

Steger Katherine A KA Avery Leon L

Genetics 20040601 2

Muscarinic acetylcholine receptors regulate the activity of neurons and muscle cells through G-protein-coupled cascades. Here, we identify a pathway through which the GAR-3 muscarinic receptor regulates both membrane potential and excitation-contraction coupling in the Caenorhabditis elegans pharyngeal muscle. GAR-3 signaling is enhanced in worms overexpressing gar-3 or lacking GPB-2, a G-protein beta-subunit involved in RGS-mediated inhibition of G(o)alpha- and G(q)alpha-linked pathways. High l ...[more]

PMID: 15238517

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Dataset Information

The GAR-3 muscarinic receptor cooperates with calcium signals to regulate muscle contraction in the Caenorhabditis elegans pharynx.

Publications

The GAR-3 muscarinic receptor cooperates with calcium signals to regulate muscle contraction in the Caenorhabditis elegans pharynx.

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