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EMBO reports 5, 5, 521–526 (2004)
doi:10.1038/sj.embor.7400142
Published online: 16 April 2004
Slow Ca2+ dynamics in pharyngeal muscles in Caenorhabditis elegans during fast pumping
Satoshi Shimozono1, Takashi Fukano1, Koutarou D Kimura2, Ikue Mori2, Yutaka Kirino3 & Atsushi Miyawaki1
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1 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
2 Laboratory of Molecular Neurobiology, Division of Biological Science, Graduate School of Science, Nagoya University, Furou-cho, Chikusa-ku, Nagoya 464-8602, Japan
3 Laboratory of Neurobiophysics, School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
To whom correspondence should be addressed
Atsushi Miyawaki Tel: +81 48 467 5917; Fax: +81 48 467 5924; E-mail: matsushi@brain.riken.go.jp
Received 4 September 2003; Accepted 10 March 2004; Published online 16 April 2004.
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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.
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