| Autor: |
ZHANG, KE-, WRIGHT, LEON, HU, PING, SPRATT, JOHN, WECHSLER, ANDREW, NORMAN BRIGGS, F. |
| Zdroj: |
Journal of Muscle Research & Cell Motility; Feb1997, Vol. 18 Issue 1, p81-90, 10p |
| Abstrakt: |
The canine latissimus dorsi was stimulated at 1 Hz via the thoracodorsal nerve for 70 days. Seven days of muscle stimulation caused muscle mass, fibre cross-sectional areas, and tetanic tensions to decrease. Fourteen days of stimulation produced marked decreasesin Ca2+-uptake rates in a membrane fraction containing sarcoplasmic reticulum. At this time there was a decline infusion frequency, but no statistically significant changes in time-to-peak tension, total contraction times, or half-relaxation times. With 42 days of stimulation a switch from the fast-twitch to the slow-twitch phenotype was indicated by elevations in the levels of expression of the slow-twitch isoform of sarco(endo)plasmic reticulum Ca2+-ATPase and myosin heavy chain-I, and increases in half-relaxation times, total contraction times and time-to-peak tensions. Decreases in muscle shortening velocity correlated negatively with increases in myosin heavy chain-I levels. Up-regulation of the slow-twitch isoform of sarco(endo)plasmic reticulum Ca2+-ATPase protein positively correlated with increases in half-relaxation times. The changes in the slow-twitch isoform of sarco(endo)plasmic reticulum Ca2+-ATPase and myosin heavy chain-I levels indicated coordinate expression of these two proteins in chronically stimulated muscles [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
Full text from SpringerLink