Abstract
Potential recordings made simultaneously from opposite ends of the cell indicate that the cytoplasmic compartment of P. caudatum is nearly isopotential. Measured decrements of the spread of steady-state potentials are in essential agreement with calculated decrements for a short cable model of similar dimensions and electrical constants. Action potentials and passively conducted pulses spread at rates of over 100 µm per msec. In contrast, metachronal waves of ciliary beat progress over the cell with velocities below 1 µm per msec. Thus, electrical activity conducted by the plasma membrane cannot account for the metachronism of ciliary beat. The electrical properties of Paramecium are responsible, however, for coordinating the reorientation of cilia (either beating or paralyzed by NiCl2) which occurs over the entire cell in response to current passed across the plasma membrane. In response to a depolarization the cilia assume an anteriorly directed orientation ("ciliary reversal" for backward locomotion). The cilia over the anterior half of the organism reverse more strongly and with shorter latency than the cilia of the posterior half. This was true regardless of the location of the polarizing electrode. Since the membrane potential was shown to be essentially uniform between both ends of the cell, the cilia of the anterior and posterior must possess different sensitivities to membrane potential.
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Selected References
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- Brokaw C. J. Bend propagation along flagella. Nature. 1966 Jan 8;209(5019):161–163. doi: 10.1038/209161a0. [DOI] [PubMed] [Google Scholar]
- HODGKIN A. L., HUXLEY A. F. A quantitative description of membrane current and its application to conduction and excitation in nerve. J Physiol. 1952 Aug;117(4):500–544. doi: 10.1113/jphysiol.1952.sp004764. [DOI] [PMC free article] [PubMed] [Google Scholar]
- HODGKIN A. L. Ionic movements and electrical activity in giant nerve fibres. Proc R Soc Lond B Biol Sci. 1958 Jan 1;148(930):1–37. doi: 10.1098/rspb.1958.0001. [DOI] [PubMed] [Google Scholar]
- Hodgkin A. L. Evidence for electrical transmission in nerve: Part I. J Physiol. 1937 Jul 15;90(2):183–210. doi: 10.1113/jphysiol.1937.sp003507. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kinosita H., Murakami A. Control of ciliary motion. Physiol Rev. 1967 Jan;47(1):53–82. doi: 10.1152/physrev.1967.47.1.53. [DOI] [PubMed] [Google Scholar]
- Naitoh Y. Control of the orientation of cilia by adenosinetriphosphate, calcium, and zinc in glycerol-extracted Paramecium caudatum. J Gen Physiol. 1969 May;53(5):517–529. doi: 10.1085/jgp.53.5.517. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Naitoh Y., Eckert R. Ciliary orientation: controlled by cell membrane or by intracellular fibrils? Science. 1969 Dec 26;166(3913):1633–1635. doi: 10.1126/science.166.3913.1633. [DOI] [PubMed] [Google Scholar]
- Naitoh Y., Eckert R. Ionic mechanisms controlling behavioral responses of paramecium to mechanical stimulation. Science. 1969 May 23;164(3882):963–965. doi: 10.1126/science.164.3882.963. [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]
- Sleigh M. A. The co-ordination and control of cilia. Symp Soc Exp Biol. 1966;20:11–31. [PubMed] [Google Scholar]