TY - JOUR
T1 - Effect of undernutrition on contractile and fatigue properties of rat diaphragm during development
AU - Brozanski, B. S.
AU - Watchko, J. F.
AU - O'Day, T. L.
AU - Guthrie, R. D.
PY - 1993
Y1 - 1993
N2 - The present study was designed to assess the effects of combined pre- and postnatal undernutrition on the in vitro contractile and fatigue properties of the rat diaphragm during development. In vitro direct stimulation of costal diaphragm from control (CTL) and undernourished (UN) rats was done on postnatal days 1, 4, 14, 21, 30, 40, 50, and 60. Combined pre- and postnatal undernutrition resulted in stunted animal growth but did not alter the diaphragm-to-total body weight ratio. Twitch contraction time, half- relaxation time, and force-frequency relationships were not consistently affected by undernutrition. Specific twitch force and specific tetanic force were also unchanged in the UN group. Fatigue resistance was high and comparable in UN and CTL groups at days 1 and 4. At day 14 and thereafter, fatigue resistance declined but was consistently higher in the UN than in the CTL group. We conclude that combined pre- and postnatal undernutrition results in a significant increase in fatigue resistance of the diaphragm compared with CTL, whereas diaphragm muscle contractile properties are not appreciably affected by prolonged undernutrition.
AB - The present study was designed to assess the effects of combined pre- and postnatal undernutrition on the in vitro contractile and fatigue properties of the rat diaphragm during development. In vitro direct stimulation of costal diaphragm from control (CTL) and undernourished (UN) rats was done on postnatal days 1, 4, 14, 21, 30, 40, 50, and 60. Combined pre- and postnatal undernutrition resulted in stunted animal growth but did not alter the diaphragm-to-total body weight ratio. Twitch contraction time, half- relaxation time, and force-frequency relationships were not consistently affected by undernutrition. Specific twitch force and specific tetanic force were also unchanged in the UN group. Fatigue resistance was high and comparable in UN and CTL groups at days 1 and 4. At day 14 and thereafter, fatigue resistance declined but was consistently higher in the UN than in the CTL group. We conclude that combined pre- and postnatal undernutrition results in a significant increase in fatigue resistance of the diaphragm compared with CTL, whereas diaphragm muscle contractile properties are not appreciably affected by prolonged undernutrition.
KW - myosin isoforms
KW - respiratory muscle
KW - specific force
UR - http://www.scopus.com/inward/record.url?scp=0027222863&partnerID=8YFLogxK
U2 - 10.1152/jappl.1993.74.5.2121
DO - 10.1152/jappl.1993.74.5.2121
M3 - Article
C2 - 8335538
AN - SCOPUS:0027222863
SN - 8750-7587
VL - 74
SP - 2121
EP - 2126
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
IS - 5
ER -