Format

Send to

Choose Destination
See comment in PubMed Commons below
J Physiol. 1995 Jan 1;482 ( Pt 1):93-107.

The effects of mechanical loading and changes of length on single guinea-pig ventricular myocytes.

Author information

  • 1Department of Physiology, University of Leeds, UK.

Abstract

1. The effects of mechanical loading and changes of length on the contraction of single guinea-pig ventricular myocytes has been investigated. 2. Cell shortening was monitored during isotonic contractions (in which the cell shortened freely) and after attaching carbon fibres of known compliance to the ends of the cell, so that the cell contracted auxotonically (the cell both shortened and developed force). 3. Mechanically loading the cells decreased the amount of shortening during a contraction and abbreviated the contraction. There were, however, no consistent changes in the action potential or the [Ca2+]i transient (measured with the fluorescent dye fura-2). 4. Increasing stimulation rate increased the size of the contraction and the [Ca2+]i transient in both isotonic and auxotonic conditions. The increase in the size of the contraction induced by an increase in stimulation rate was greater in auxotonic conditions but the increase in the size of the [Ca2+]i transient was not. 5. When cells were stretched, there was a step increase in the size of the contraction and a prolongation of its time course. However, neither the size nor the time course of the accompanying [Ca2+]i transient was significantly altered by this intervention. 6. When a stretch was maintained, a further, slow increase in the size of the contraction occurred during the following 3-11 min, in about half the cells studied. The probability of this slow response occurring was increased if the initial degree of activation of the cell was decreased. 7. These data suggest that the mechanisms underlying the responses to mechanical loading and changes of length are the same in both multicellular and single cell preparations of cardiac muscle.

PMID:
7730993
PMCID:
PMC1157756
[PubMed - indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Wiley Icon for PubMed Central
    Loading ...
    Write to the Help Desk