Physical and biochemical energy balance during an isometric tetanus and steady state recovery in frog sartorius at 0 degree C.
Open Access
- 1 March 1983
- journal article
- Published by Rockefeller University Press in The Journal of general physiology
- Vol. 81 (3), 337-354
- https://doi.org/10.1085/jgp.81.3.337
Abstract
Frog sartorius muscle stimulated isometrically for 3 s every 256 s to attain a steady state in which initial heat (QI), recovery heat (QR), rate of O2 consumption (JO2), and isometric force (PO) generated are constant for each cycle. For a 3-s tetanus given every 256 s, JO2 was 0.106 mumol/(min . g blotted weight), approximately 71% of the maximum rate observed, whereas lactate production was negligible under these conditions. QI, QT(= QI + QR), and QT/QI were 88.2, 181.5, 2.06 mJ/g blotted weight, respectively. The high-energy phosphate breakdown (delta approximately P) breakdown during the first 3-s tetanus was not different from that during a contraction in the steady state and averaged 1.1 mumol/g blotted weight. Less than half of the initial heat could be accounted for in terms of the extent of the known chemical reactions occurring during contraction. From the stoichiometry of the theoretical biochemical pathways, the amount of ATP synthesized in the steady state exceeds delta approximately P during contraction by more than twofold, corresponding to an apparent ADP:O ratio of 1.5. If it is assumed that carbohydrate oxidation is the only net chemical reaction in the steady state, the total heat production can be explained on the basis of the measured JO2. Under this assumption, heat production during recovery was less than that expected on the basis of the oxygen consumption and delta approximately P during contraction. These observations support the hypothesis that the unexplained enthalpy production and low apparent ADP:O ratio are causally related, i.e., that the reaction(s) producing the unexplained heat during contraction is reversed during the recovery period.Keywords
This publication has 18 references indexed in Scilit:
- The relationship between initial creatine phosphate breakdown and recovery oxygen consumption for a single isometric tetanus of the frog sartorius muscle at 20 degrees C.The Journal of general physiology, 1979
- Energy changes and muscular contraction.Physiological Reviews, 1978
- Skeletal Muscle Energetics and MetabolismAnnual Review of Physiology, 1978
- Characterization of frog muscle mitochondriaAmerican Journal of Physiology-Cell Physiology, 1978
- Relationship between initial chemical reactions and oxidative recovery metabolism for single isometric contractions of frog sartorius at 0 degrees C.Journal Of Physiology-London, 1976
- Aerobic recovery metabolism following a single isometric tetanus in frog sartorius muscle at 0 degrees C.Journal Of Physiology-London, 1976
- Heat production and fluorescence changes of toad sartorius muscle during aerobic recovery after a short tetanusJournal Of Physiology-London, 1972
- Heat work and phosphorylcreatine break‐down in muscleJournal Of Physiology-London, 1968
- Hydrogen-ion concentration changes in frog's muscle following activityJournal Of Physiology-London, 1940
- The relation between total and initial heat in single muscle twitchesJournal Of Physiology-London, 1934