EFFECT OF ACUTE STARVATION ON RAT DIAPHRAGM FUNCTION

The effects of 130 h of acute starvation on diaphragm contractility fa tigue were studied in isolated rat diaphragm strip preparations with p hrenic nerve stimulation. Compared with controls, starvation produced a reduction in body and diaphragm weights. Twitch and tetanic tensions were reduced by starvation; however, when the force was calculated as the strength (normalized for the weight or muscle cross-section area of the diaphragm), no difference was observed between the control and experimental groups. Starvation induced a significant downward shift i n the force-frequency relationship, and also increased diaphragm fatig ability, but it had no effect on twitch contraction and relaxation tim e. We conclude that 130 h of acute starvation decreases diaphragmatic force and endurance, but the strength does not change, because of the reducing diaphragmatic mass.