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Energetics of relaxation in frog muscle
Author(s) -
Curtin Nancy A.,
Woledge Roger C.
Publication year - 1974
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1974.sp010535
Subject(s) - energetics , relaxation (psychology) , biophysics , chemistry , anatomy , biology , neuroscience , ecology
1. Changes in the levels of phosphocreatine (PCr) and ATP during relaxation after tetanic contraction have been observed and compared with the heat + work production during the same period. 2. The results were the same using 2 sec or 15 sec tetani and using 15 or 30 Hz stimulation. 3. During relaxation the mean chemical change (of ATP + PCr) was −0·105 ± 0·078 μmol/g muscle ( n = 53). This change is less than would be required to explain the heat + work produced. 4. The PCr split during both 2 sec and 15 sec tetani (up to the last stimulus) was less than would be required to explain the heat + work produced. This confirms previous experiments. 5. It is concluded that the discrepancy between chemical change and heat + work production does not diminish during relaxation but actually increases.