This study investigated the effects of refeeding (RF) after chronic undernutrition (UN), to determine whether RF would reverse UN-induced changes in diaphragm force capacity (Ameredes BT, Am J Respir Crit Care Med 1995;151:A156). RF, as re-establishment of ad lib feeding after UN [30 wk. restricted caloric intake, ∼50% body weight difference from ad lib-fed controls (C)], restored body weight to that of C. Specific force (Fs) development was monitored before, at the end, and one hr. after, repetitive isometric-contraction trials (15°C, 560 ms trains, 20 Hz, 40% duty cycle, 5 min. trial); force-frequency (F-f) relationships were produced before fatigue, and with recovery. Initial force (Fs,) was not different across groups (mean=6.6 N/cm2). Post-fatigue RF diaphragm Fs was similar to UN (31 % and 33%of Fs,), both being significantly higher than post-fatigue C values (23% of Fsi, p<0.05). Recovery of Fs, and the F-f relationship, one hr. after fatigue, was complete in UN diaphragms, but remained depressed in RF diaphragms (75% of Fsi, p<0.05). Pre-fatigue (358ms) and recovery (356ms) relaxation rates (1/2RT) remained prolonged in UN diaphragms as compared to C (235ms, p<0.05), and were not significantly altered by RF (273 and 251ms, respectively). These results indicate that RF does not reverse chronic UN-induced changes in force-capacity of the rat diaphragm in vilro.
|Original language||English (US)|
|State||Published - Dec 1 1996|
ASJC Scopus subject areas
- Molecular Biology