title: Slow Ca2+ dynamics in pharyngeal muscles in Caenorhabditis elegans during fast pumping.
abstract: The pharyngeal muscles of Caenorhabditis elegans are composed of the corpus, isthmus and terminal bulb from anterior to posterior. These components are excited in a coordinated fashion to facilitate proper feeding through pumping and peristalsis. We analysed the spatiotemporal pattern of intracellular calcium dynamics in the pharyngeal muscles during feeding. We used a new ratiometric fluorescent calcium indicator and a new optical system that allows simultaneous illumination and detection at any two wavelengths. Pumping was observed with fast, repetitive and synchronous spikes in calcium concentrations in the corpus and terminal bulb, indicative of electrical coupling throughout the muscles. The posterior isthmus, however, responded to only one out of several pumping spikes to produce broad calcium transients, leading to peristalsis, the slow and gradual motion needed for efficient swallows. The excitation-calcium coupling may be uniquely modulated in this region at the level of calcium channels on the plasma membrane.
authors.affiliation: Laboratory for Cell Function Dynamics, Brain Science Institute, The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako-city, Saitama, 351-0198, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Shimozono
authors.forename: Takashi
authors.initials: T
authors.lastname: Fukano
authors.forename: Koutarou D
authors.initials: KD
authors.lastname: Kimura
authors.forename: Ikue
authors.initials: I
authors.lastname: Mori
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kirino
authors.forename: Atsushi
authors.initials: A
authors.lastname: Miyawaki
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D009119:Muscle Contraction; D009132:Muscles / Q000502:physiology; D010528:Peristalsis; D010614:Pharynx; D019837:Ryanodine Receptor Calcium Release Channel / Q000235:genetics / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; D019837:Ryanodine Receptor Calcium Release Channel; C438601:Unc-68 protein, C elegans; D002118:Calcium