NDLI: Effect of intracellular pH on force and heat production in isometric contraction of frog muscle fibres.

Content Provider	PubMed Central
Author	Curtin, N. A. Kometani, K. Woledge, R. C.
Abstract	1. The intracellular pH (pHi) of live fibres from the anterior tibialis of the frog Rana temporaria was measured at 10 degrees C (using pH-sensitive microelectrodes) in Ringer solutions containing a fixed bicarbonate concentration (20 mM) and varying PCO2 concentrations of 0.5-54%. As extracellular pH was changed from 7.99 to 6.00, mean pHi changed from 7.24 to 5.97. Similar results were obtained at 20 degrees C. 2. In parallel experiments force and rate of heat production in 4 s isometric tetani at 10 degrees C were measured, and compared to control observations (5% CO2, pHi 6.80). 3. As the fibres became more acid (to pHi 5.95), force and heat rate were progressively reduced (to 0.75 and 0.71 of the control values, respectively). 4. As the fibres became more alkaline (to pHi 7.26), force increased slightly (by a maximum of 0.03 of the control value) but heat rate did not increase. 5. When the dependence on pH of the molar enthalpy change for phosphocreatine splitting is taken into account, these results indicate that the force-time integral per cross-bridge cycle increases with pHi over this range.
Ending Page	104
Starting Page	93
File Format	PDF
ISSN	14697793
e-ISSN	14697793
Journal	The Journal of Physiology
Volume Number	396
Language	English
Publisher Date	1988-02-01
Access Restriction	Open
Subject Keyword	Research in Higher Education
Content Type	Text
Resource Type	Article
Subject	Physiology Sports Science

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Effect of intracellular pH on force and heat production in isometric contraction of frog muscle fibres.