Abstract
The duration of ciliary reversal of Paramecium caudatum in response to changes in external ionic factors was determined with various ionic compositions of both equilibration and stimulation media. The reversal response was found to occur when calcium ions bound by an inferred cellular cation exchange system were liberated in exchange for externally applied cations other than calcium. Factors which affect the duration of the response were (a) initial amount of calcium bound by the cation exchange system, (b) final amount of calcium bound by the system after equilibration with the stimulation medium, and (c) concentration of calcium ions in the stimulation medium. An empirical equation is presented which relates the duration of the response to these three factors. On the basis of these and previously published data, the following hypothesis is proposed for the mechanism underlying ciliary reversal in response to cationic stimulation: Ca++ liberated from the cellular cation exchange system activates a contractile system which is energized by ATP. Contraction of this component results in the reversal of effective beat direction of cilia by a mechanism not yet understood. The duration of reversal in live paramecia is related to the time course of bound calcium release.
Full Text
The Full Text of this article is available as a PDF (979.6 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Gibbons I. R., Rowe A. J. Dynein: A Protein with Adenosine Triphosphatase Activity from Cilia. Science. 1965 Jul 23;149(3682):424–426. doi: 10.1126/science.149.3682.424. [DOI] [PubMed] [Google Scholar]
- HUXLEY A. F. MUSCLE. Annu Rev Physiol. 1964;26:131–152. doi: 10.1146/annurev.ph.26.030164.001023. [DOI] [PubMed] [Google Scholar]
- JAHN T. L. The mechanism of ciliary movement. II. Ion antagonism and ciliary reversal. J Cell Comp Physiol. 1962 Dec;60:217–228. doi: 10.1002/jcp.1030600305. [DOI] [PubMed] [Google Scholar]
- Naitoh Y. Reversal response elicited in nonbeating cilia of paramecium by membrane depolarizatin. Science. 1966 Nov 4;154(3749):660–662. doi: 10.1126/science.154.3749.660. [DOI] [PubMed] [Google Scholar]
- Naitoh Y., Yasumasu I. Binding of Ca ions by Paramecium caudatum. J Gen Physiol. 1967 May;50(5):1303–1310. doi: 10.1085/jgp.50.5.1303. [DOI] [PMC free article] [PubMed] [Google Scholar]