QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online February 20, 2004
Journal of Experimental Biology 207, 1093-1099 (2004)
Published by The Company of Biologists 2004
doi: 10.1242/jeb.00852

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Suzuki, S. Articles by Sugi, H. Search for Related Content PubMed PubMed Citation Articles by Suzuki, S. Articles by Sugi, H. Social Bookmarking                         What's this?

Intracellular calcium translocation during the contraction–relaxation cycle in scorpionfish swimbladder muscle

Suechika Suzuki^1,*, Naoki Hino² and Haruo Sugi¹

¹ Department of Physiology, School of Medicine, Teikyo University, 2-11-1, Kaga, Itabashi-ku, Tokyo 173-8605, Japan
² Department of Physiology, Juntendo Medical College of Nursing, 2-2, Takasu, Urayasu City, Chiba 279-0023, Japan

^* Author for correspondence at present address: Department of Biological Sciences, School of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka-City, Kanagawa 259-1293, Japan (e-mail: sugi{at}med.teikyo-u.ac.jp)

Accepted 3 December 2003

To examine intracellular Ca²⁺ translocation during the contraction–relaxation cycle in vertebrate striated muscle, electron probe X-ray microanalysis was performed on the swimbladder muscle (SBM) fibres of a scorpionfish Sebastiscus marmoratus. The SBM fibres were rapidly frozen at rest, during contraction and at various times after the onset of relaxation. Changes in calcium distribution in the components of the sarcoplasmic reticulum (SR) were examined on the SBM fibre cryosections. In resting fibres, the calcium concentration was highest around the boundary between the A and I bands (A–I boundary), where the terminal cisternae (TC) were located. In contracting fibres, the calcium concentration decreased around the A–I boundary, while it increased in all other regions of the sarcomere, indicating Ca²⁺ release from the TC into the myoplasm. During relaxation, the calcium concentration first increased around the regions, where the fenestrated collars (FC) and the longitudinal tubules (LT) were located, and then gradually returned to the levels seen in resting fibres. These results support the view that, after the onset of relaxation in the SBM fibres, Ca²⁺ in the myoplasm is first taken up by the FC and the LT, and then gradually returns to the TC.

Key words: scorpionfish, Sebastiscus marmoratus, swimbladder muscle, intracellular Ca translocation, contraction–relaxation cycle, electron probe X-ray microanalysis, sarcoplasmic reticulum, Ca²⁺ release, Ca²⁺ uptake

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				T. Kobayashi, T. Daimon, I. Shirakawa, S. Chaen, and H. Sugi Electrical and mechanical properties and mode of innervation in scorpionfish sound-producing muscle fibres J. Exp. Biol., October 1, 2004; 207(21): 3757 - 3763. [Abstract] [Full Text] [PDF]