Abstract
The electrical transients produced on the isolated abdominal skin obtained from Bufo arenarum Hensel, under the influence of inward current pulses of constant intensity have been studied. When both faces of the skin are bathed with Ringer's solution, short pulses of inward current give rise to transient variations of the potential difference between both faces of the skin with "all-or-nothing" characteristics (action potentials, AP). When the outer face is bathed with a modified Ringer solution with low sodium content (2.4 mM), the transients are longer and they are only evident when the pulse is several hundred milliseconds long. With even longer pulses (several seconds) a repetitive activity can be elicited, with the electrical characteristics of a "pacemaker" activity. In all these "excitability" phenomena Na+ may be replaced by Li+ in the outer solution. The logarithm of the duration of AP's is inversely related to the logarithm of the increase in concentration of Na+ or Li+ in the solution bathing the external face of the skin. The duration of AP's is increased when the Ca++ concentration in the outer solution is raised. This effect is more evident with low sodium concentration on the outside. The evolution of the slope conductance during repetitive activity has been determined. The site and mechanisms of the "excitable" behavior of the skin and the induced repetitive activity are discussed. Under the experimental conditions employed the behavior of the skin is compared with that of normally excitable plasma membranes.
Full Text
The Full Text of this article is available as a PDF (968.2 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Biber T. U., Chez R. A., Curran P. F. Na transport across frog skin at low external Na concentrations. J Gen Physiol. 1966 Jul;49(6):1161–1176. doi: 10.1085/jgp.0491161. [DOI] [PMC free article] [PubMed] [Google Scholar]
- CEREIJIDO M., HERRERA F. C., FLANIGAN W. J., CURRAN P. F. THE INFLUENCE OF NA CONCENTRATION ON NA TRANSPORT ACROSS FROG SKIN. J Gen Physiol. 1964 May;47:879–893. doi: 10.1085/jgp.47.5.879. [DOI] [PMC free article] [PubMed] [Google Scholar]
- CHOWDHURY T. K., SNELL F. M. A MICROELECTRODE STUDY OF ELECTRICAL POTENTIALS IN FROG SKIN AND TOAD BLADDER. Biochim Biophys Acta. 1965 Mar 29;94:461–471. doi: 10.1016/0926-6585(65)90054-3. [DOI] [PubMed] [Google Scholar]
- CRANEFIELD P. F., HOFFMAN B. F. Propagated repolarization in heart muscle. J Gen Physiol. 1958 Mar 20;41(4):633–649. doi: 10.1085/jgp.41.4.633. [DOI] [PMC free article] [PubMed] [Google Scholar]
- CURRAN P. F., HERRERA F. C., FLANIGAN W. J. The effect of Ca and antidiuretic hormone on Na transport across frog skin. II. Sites and mechanisms of action. J Gen Physiol. 1963 May;46:1011–1027. doi: 10.1085/jgp.46.5.1011. [DOI] [PMC free article] [PubMed] [Google Scholar]
- FINKELSTEIN A. ELECTRICAL EXCITABILITY OF ISOLATED FROG SKIN AND TOAD BLADDER. J Gen Physiol. 1964 Jan;47:545–565. doi: 10.1085/jgp.47.3.545. [DOI] [PMC free article] [PubMed] [Google Scholar]
- FINKELSTEIN A. Electrical excitability of isolated frog skin. Nature. 1961 Jun 17;190:1119–1120. doi: 10.1038/1901119a0. [DOI] [PubMed] [Google Scholar]
- Farquhar M. G., Palade G. E. Adenosine triphosphatase localization in amphibian epidermis. J Cell Biol. 1966 Aug;30(2):359–379. doi: 10.1083/jcb.30.2.359. [DOI] [PMC free article] [PubMed] [Google Scholar]
- KOEFOED-JOHNSEN V., USSING H. H. The nature of the frog skin potential. Acta Physiol Scand. 1958 Jun 2;42(3-4):298–308. doi: 10.1111/j.1748-1716.1958.tb01563.x. [DOI] [PubMed] [Google Scholar]
- LINDLEY B. D., HOSHIKO T. THE EFFECTS OF ALKALI METAL CATIONS AND COMMON ANIONS ON THE FROG SKIN POTENTIAL. J Gen Physiol. 1964 Mar;47:749–771. doi: 10.1085/jgp.47.4.749. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Noble D. Applications of Hodgkin-Huxley equations to excitable tissues. Physiol Rev. 1966 Jan;46(1):1–50. doi: 10.1152/physrev.1966.46.1.1. [DOI] [PubMed] [Google Scholar]
- Snell F. M., Chowdhury T. K. Contralateral effects of sodium and potassium on the electrical potential in frog skin and toad bladder. Nature. 1965 Jul 3;207(992):45–46. doi: 10.1038/207045a0. [DOI] [PubMed] [Google Scholar]
- WHITTEMBURY G. ELECTRICAL POTENTIAL PROFILE OF THE TOAD SKIN EPITHELIUM. J Gen Physiol. 1964 Mar;47:795–808. doi: 10.1085/jgp.47.4.795. [DOI] [PMC free article] [PubMed] [Google Scholar]