Glucose metabolism of isolated perfused rat hemidiaphragms stimulated via the phrenic nerve
Few investigations using indirect electrical stimulation of diaphragm muscles have measured metabolic pathways involved in energy production. In this study, hemidiaphragm (HD) glucose catabolism was determined while resting and during stimulation with trains of either five (T5) or fifteen (T15) 50 Hz bursts per second. Tissues were perfused and bathed in HEPES buffer pH 7.4 equilibrated with 100% O/sub 2/, and containing 11mM (U-/sup 14/C)(5-/sup 3/H) D-glucose. Resting glucose catabolism via the Emden-Meyerhof pathway was indicated by a /sup 3/H/sub 2/O production rate of 1.45 +/- 0.07 ..mu..mol/h/HD (+/- S.E.M., n = 3), of which 47% was recovered as /sup 14/C lactate. Following an initial decline in peak isometric tension from 100 g within the first 30 min, T5 and T15 stimulation gave constant tensions of 48 and 22 g during the next 60 min, respectively. These tensions were associated with linear rates of /sup 3/H/sub 2/O production of 2.93 +/- 0.41 and 2.84 +/- 0.25 ..mu..mol/h/HD (+/- S.E.M., n = 3). Since T5 and T15 stimulation had no significant effect on lactate formation from either exogenous or endogenous sources, the observed increased glycolytic rate was assumed to be associated with enhanced mitochondrial oxidation of glucose carbons to CO/sub 2/. Increased oxidative catabolism of glucose could therefore be correlated with the increased energy demands of a stimulated diaphragm.
- Research Organization:
- Johns Hopkins Univ. School of Hygiene and Public Health, Baltimore, MD
- OSTI ID:
- 5277807
- Report Number(s):
- CONF-8604222-; TRN: 86-030478
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:3; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
- Country of Publication:
- United States
- Language:
- English
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GLUCOSE
METABOLISM
MUSCLES
BIOCHEMISTRY
BIOLOGICAL PATHWAYS
CARBON 14 COMPOUNDS
CARBON DIOXIDE
LACTATES
NERVES
PERFUSED TISSUES
RATS
TRITIUM COMPOUNDS
WATER
ALDEHYDES
ANIMAL TISSUES
ANIMALS
BODY
CARBOHYDRATES
CARBON COMPOUNDS
CARBON OXIDES
CARBOXYLIC ACID SALTS
CHALCOGENIDES
CHEMISTRY
HEXOSES
HYDROGEN COMPOUNDS
LABELLED COMPOUNDS
MAMMALS
MONOSACCHARIDES
NERVOUS SYSTEM
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
RODENTS
SACCHARIDES
TISSUES
VERTEBRATES
550501* - Metabolism- Tracer Techniques