Abstract
A vibrating microelectrode, or vibrating probe (Jaffe and Nuccitelli, 1974), was used to map the pattern of artificially created electric currents flowing around single muscle fibers at the edge of frog cutaneous pectoris muscles. When a muscle fiber was impaled with a micropipette, a "point sink" of current was often created at the site of impalement because of injury to the cell membrane. Current, being drawn from the flanking membrane, flowed into the cell only at this point. This defined current allowed us to map the spatial resolving power of the vibrating probe by moving to different positions near the impalement site. The results suggest that under our experimental conditions the limit of resolution is a few tens of micrometers. The results were fit reasonably well by a computer model. Current was also passed through a micropipette and mapped at various positions with the vibrating probe. In this case, the current flowed to a remote reference electrode. With the current electrode in the extracellular fluid, the probe signal decayed as the inverse square of the distance, as expected. With the current electrode placed intracellularly, current was funneled along the muscle fiber axis, reflecting its cable-like properties. The signal recorded by the vibrating probe was altered accordingly, and the results could be well fit by a simple model.
Full Text
The Full Text of this article is available as a PDF (850.7 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Betz W. J., Caldwell J. H., Ribchester R. R., Robinson K. R., Stump R. F. Endogenous electric field around muscle fibres depends on the Na+-K+ pump. Nature. 1980 Sep 18;287(5779):235–237. doi: 10.1038/287235a0. [DOI] [PubMed] [Google Scholar]
- DOWBEN R. M., ROSE J. E. A metal-filled microelectrode. Science. 1953 Jul 3;118(3053):22–24. doi: 10.1126/science.118.3053.22. [DOI] [PubMed] [Google Scholar]
- Foskett J. K., Scheffey C. The chloride cell: definitive identification as the salt-secretory cell in teleosts. Science. 1982 Jan 8;215(4529):164–166. doi: 10.1126/science.7053566. [DOI] [PubMed] [Google Scholar]
- Jaffe L. F., Nuccitelli R. An ultrasensitive vibrating probe for measuring steady extracellular currents. J Cell Biol. 1974 Nov;63(2 Pt 1):614–628. doi: 10.1083/jcb.63.2.614. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jaffe L. F., Woodruff R. I. Large electrical currents traverse developing Ceropia follicles. Proc Natl Acad Sci U S A. 1979 Mar;76(3):1328–1332. doi: 10.1073/pnas.76.3.1328. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Robinson K. R. Electrical currents through full-grown and maturing Xenopus oocytes. Proc Natl Acad Sci U S A. 1979 Feb;76(2):837–841. doi: 10.1073/pnas.76.2.837. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Stump R. F., Robinson K. R., Harold R. L., Harold F. M. Endogenous electrical currents in the water mold Blastocladiella emersonii during growth and sporulation. Proc Natl Acad Sci U S A. 1980 Nov;77(11):6673–6677. doi: 10.1073/pnas.77.11.6673. [DOI] [PMC free article] [PubMed] [Google Scholar]