Abstract
If the load on a tetanized fiber is abruptly changed to a new steady value, the ensuing fiber length change shows the well-known 'isotonic velocity transient', in which the velocity oscillates before settling at some steady value. We studied sarcomere dynamics during these transients using two methods: optical diffraction and a segment-length method. Our principal aim was to determine whether these transients might be a reflection of the fact that sarcomere shortening is often found to be stepwise. We found that pauses in sarcomere shortening occurred during the low-velocity phases of the transient and that steps of sarcomere shortening occurred during the high-velocity phases. Thus the isotonic transient appears to rise from the steps. In addition to the isotonic transient, we studied the well-known isometric transient, in which fiber length is abruptly changed, and ensuing tension response is measured. Again, we found that the transient may be a reflection of the stepwise shortening pattern.
Original language | English (US) |
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Pages (from-to) | C266-C278 |
Journal | American Journal of Physiology - Cell Physiology |
Volume | 259 |
Issue number | 2 28-3 |
DOIs | |
State | Published - 1990 |
Externally published | Yes |
Keywords
- Diffraction
- Load clamp
- Method
- Pauses
- Segment-length
- Servo-control
- Steps
ASJC Scopus subject areas
- Physiology
- Cell Biology