Abstract
1. A voltage-clamp technique for the measurement of effective membrane capacity is described and its theoretical basis given in an Appendix. Unlike most other methods used so far, the present technique does not depend on the assumption of a particular equivalent circuit for muscle membrane.
2. With this technique, we have re-examined the effect of media of low ion content on the effective membrane capacity Ceff. In fibres where potassium conductance is blocked by Rb, Ceff failed to show any appreciable dependence on ionic strength (between 0·015 and 0·29 M) or conductivity (between 0·86 and 13·4 mmho/cm) of the bathing medium.
3. Low conductivity can reduce Ceff in fibres of moderately high K-conductance. However, in all cases explored here, Ceff had values well above the 2 μF/cm2 found in glycerol-treated fibres, indicating that passive spread of potential displacements from surface into the tubular system could still occur.
4. The changes in Ceff observed under conditions of moderately high K-conductance are explicable as a result of potential decrements in the transverse tubules, which would be expected when the wall conductance there is high, and the conductivity of the tubule lumen is low.
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Selected References
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- ADRIAN R. H. The effect of internal and external potassium concentration on the membrane potential of frog muscle. J Physiol. 1956 Sep 27;133(3):631–658. doi: 10.1113/jphysiol.1956.sp005615. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Adrian R. H., Almers W. Measurement of membrane capacity in skeletal muscle. Nat New Biol. 1973 Mar 14;242(115):62–64. doi: 10.1038/newbio242062a0. [DOI] [PubMed] [Google Scholar]
- Adrian R. H., Chandler W. K., Hodgkin A. L. The kinetics of mechanical activation in frog muscle. J Physiol. 1969 Sep;204(1):207–230. doi: 10.1113/jphysiol.1969.sp008909. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Adrian R. H., Costantin L. L., Peachey L. D. Radial spread of contraction in frog muscle fibres. J Physiol. 1969 Sep;204(1):231–257. doi: 10.1113/jphysiol.1969.sp008910. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Almers W. Potassium conductance changes in skeletal muscle and the potassium concentration in the transverse tubules. J Physiol. 1972 Aug;225(1):33–56. doi: 10.1113/jphysiol.1972.sp009928. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Almers W. The decline of potassium permeability during extreme hyperpolarization in frog skeletal muscle. J Physiol. 1972 Aug;225(1):57–83. doi: 10.1113/jphysiol.1972.sp009929. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Birks R. I., Davey D. F. An analysis of volume changes in the T-tubes of frog skeletal muscle exposed to sucrose. J Physiol. 1972 Apr;222(1):95–111. doi: 10.1113/jphysiol.1972.sp009789. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Eisenberg R. S., Gage P. W. Ionic conductances of the surface and transverse tubular membranes of frog sartorius fibers. J Gen Physiol. 1969 Mar;53(3):279–297. doi: 10.1085/jgp.53.3.279. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Eisenberg R. S., Vaughan P. C., Howell J. N. A theoretical analysis of the capacitance of muscle fibers using a distributed model of the tubular system. J Gen Physiol. 1972 Mar;59(3):360–373. doi: 10.1085/jgp.59.3.360. [DOI] [PMC free article] [PubMed] [Google Scholar]
- FALK G., FATT P. LINEAR ELECTRICAL PROPERTIES OF STRIATED MUSCLE FIBRES OBSERVED WITH INTRACELLULAR ELECTRODES. Proc R Soc Lond B Biol Sci. 1964 Apr 14;160:69–123. doi: 10.1098/rspb.1964.0030. [DOI] [PubMed] [Google Scholar]
- FATT P., KATZ B. An analysis of the end-plate potential recorded with an intracellular electrode. J Physiol. 1951 Nov 28;115(3):320–370. doi: 10.1113/jphysiol.1951.sp004675. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Freygang W. H., Jr, Rapoport S. I., Peachey L. D. Some relations between changes in the linear electrical properties of striated muscle fibers and changes in ultrastructure. J Gen Physiol. 1967 Nov;50(10):2437–2458. doi: 10.1085/jgp.50.10.2437. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gage P. W., Eisenberg R. S. Capacitance of the surface and transverse tubular membrane of frog sartorius muscle fibers. J Gen Physiol. 1969 Mar;53(3):265–278. doi: 10.1085/jgp.53.3.265. [DOI] [PMC free article] [PubMed] [Google Scholar]
- HODGKIN A. L., HOROWICZ P. The effect of sudden changes in ionic concentrations on the membrane potential of single muscle fibres. J Physiol. 1960 Sep;153:370–385. doi: 10.1113/jphysiol.1960.sp006540. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hodgkin A. L., Nakajima S. Analysis of the membrane capacity in frog muscle. J Physiol. 1972 Feb;221(1):121–136. doi: 10.1113/jphysiol.1972.sp009743. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hodgkin A. L., Nakajima S. The effect of diameter on the electrical constants of frog skeletal muscle fibres. J Physiol. 1972 Feb;221(1):105–120. doi: 10.1113/jphysiol.1972.sp009742. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Peachey L. D. The sarcoplasmic reticulum and transverse tubules of the frog's sartorius. J Cell Biol. 1965 Jun;25(3 Suppl):209–231. doi: 10.1083/jcb.25.3.209. [DOI] [PubMed] [Google Scholar]
- Rapoport S. I., Peachey L. D., Goldstein D. A. Swelling of the transverse tubular system in frog sartorius. J Gen Physiol. 1969 Aug;54(2):166–177. doi: 10.1085/jgp.54.2.166. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schneider M. F., Chandler W. K. Voltage dependent charge movement of skeletal muscle: a possible step in excitation-contraction coupling. Nature. 1973 Mar 23;242(5395):244–246. doi: 10.1038/242244a0. [DOI] [PubMed] [Google Scholar]
- Schneider M. F. Linear electrical properties of the transverse tubules and surface membrane of skeletal muscle fibers. J Gen Physiol. 1970 Nov;56(5):640–671. doi: 10.1085/jgp.56.5.640. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vaughan P. C., Howell J. N., Eisenberg R. S. The capacitance of skeletal muscle fibers in solutions of low ionic strength. J Gen Physiol. 1972 Mar;59(3):347–359. doi: 10.1085/jgp.59.3.347. [DOI] [PMC free article] [PubMed] [Google Scholar]