title: A novel method to study contraction characteristics of a single cardiac myocyte using carbon fibers.
abstract: To facilitate cardiac muscle research, we developed a novel method by which the force and length of a single ventricular myocyte can be recorded with a pair of carbon graphite fibers attached firmly to both ends. One fiber was stiff, whereas the other fiber was compliant to allow the recording of force and shortening during twitch contractions. The image of the compliant carbon fiber was projected onto a pair of photodiodes, and their output was fed to a piezoelectric transducer after variable amplifications to alter the effective compliance of the carbon fiber. Thus contraction of the myocyte was induced under virtually isometric conditions as well as under auxotonic conditions. We obtained a bell-shaped relation between the compliance under an auxotonic load and the work output of the myocyte, which was directly related to myocyte performance in the heart. Because it is easy to attach myocytes to the experimental apparatus, the present method would allow us to study cardiac muscle mechanics at the cellular and molecular levels.
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655, Japan.
authors.forename: S I
authors.initials: SI
authors.lastname: Yasuda
authors.forename: S
authors.initials: S
authors.lastname: Sugiura
authors.forename: N
authors.initials: N
authors.lastname: Kobayakawa
authors.forename: H
authors.initials: H
authors.lastname: Fujita
authors.forename: H
authors.initials: H
authors.lastname: Yamashita
authors.forename: K
authors.initials: K
authors.lastname: Katoh
authors.forename: Y
authors.initials: Y
authors.lastname: Saeki
authors.forename: H
authors.initials: H
authors.lastname: Kaneko
authors.forename: Y
authors.initials: Y
authors.lastname: Suda
authors.forename: R
authors.initials: R
authors.lastname: Nagai
authors.forename: H
authors.initials: H
authors.lastname: Sugi
mesh_terms: D000818:Animals; D002316:Cardiotonic Agents / Q000494:pharmacology; D002469:Cell Separation; D003187:Compliance; D006108:Graphite; D007537:Isometric Contraction / Q000187:drug effects / Q000502:physiology; D007545:Isoproterenol / Q000494:pharmacology; D007551:Isotonic Contraction / Q000502:physiology; D008297:Male; D008839:Microelectrodes; D009200:Myocardial Contraction / Q000187:drug effects / Q000502:physiology*; D009206:Myocardium / Q000166:cytology*; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D014159:Transducers
chemical_list: D002316:Cardiotonic Agents; D006108:Graphite; D007545:Isoproterenol