Abstract
The action potential which elicits luminescence in Noctiluca is recorded from the flotation vacuole as a transient all-or-none hyperpolarization in response to either local or general application of inward (bath to vacuole) current. Experiments were performed to determine whether the unorthodox polarities of both the stimulus current and the potential response resulted from uncommon bioelectric mechanisms or from special morphological features of this species. The findings all indicate that the action potential belongs to the familiar class of responses which have their origin in voltage- and time-dependent selective increases in membrane permeability, and that morphological factors account for the observed deviations from normal behavior. Both the stimulus and the response have orthodox polarities provided the vacuole is designated as an "external" extracytoplasmic compartment. Differential recording between vacuole and cytoplasm showed that the action potential occurs across the vacuolar membrane, with the cytoplasmic potential, which at rest is negative with respect to the vacuole, overshooting zero and reversing sign to become transiently electropositive. The rising phase of the action potential therefore depends on active current flow through the vacuolar membrane from the vacuole into the cytoplasm. Propagation of the action potential over the subspherical cell from the locus of stimulation is thought to depend largely on the core conductor properties of the thin perivacuolar shell of cytoplasm which is bounded on its inner surface by the excitable membrane and on its outer surface by inexcitable membranes.
Full Text
The Full Text of this article is available as a PDF (1.4 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- CHANG J. J. Electrophysiological studies of a non-luminescent form of the dinoflagellate Noctiluca miliaris. J Cell Comp Physiol. 1960 Aug;56:33–42. doi: 10.1002/jcp.1030560106. [DOI] [PubMed] [Google Scholar]
- EYZAGUIRRE C., KUFFLER S. W. Processes of excitation in the dendrites and in the soma of single isolated sensory nerve cells of the lobster and crayfish. J Gen Physiol. 1955 Sep 20;39(1):87–119. doi: 10.1085/jgp.39.1.87. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Eckert R. I. Specific Nature of Triggering Events. Science. 1965 Mar 5;147(3662):1140–1142. doi: 10.1126/science.147.3662.1140. [DOI] [PubMed] [Google Scholar]
- Eckert R. II. Asynchronous Flash Initiation by a Propagated Triggering Potential. Science. 1965 Mar 5;147(3662):1142–1145. doi: 10.1126/science.147.3662.1142. [DOI] [PubMed] [Google Scholar]
- Eckert R., Reynolds G. T. The subcellular origin of bioluminescence in Noctiluca miliaris. J Gen Physiol. 1967 May;50(5):1429–1458. doi: 10.1085/jgp.50.5.1429. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Eckert R., Sibaoka T. Bioelectric regulation of tentacle movement in a dinoflagellate. J Exp Biol. 1967 Dec;47(3):433–446. doi: 10.1242/jeb.47.3.433. [DOI] [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]
- GRAY J. A., SATO M. Properties of the receptor potential in Pacinian corpuscles. J Physiol. 1953 Dec 29;122(3):610–636. doi: 10.1113/jphysiol.1953.sp005025. [DOI] [PMC free article] [PubMed] [Google Scholar]
- HISADA M. Membrane resting and action potentials from a protozoan, Noctiluca scintillans. J Cell Physiol. 1957 Aug;50(1):57–71. doi: 10.1002/jcp.1030500105. [DOI] [PubMed] [Google Scholar]
- JENERICK H. PHASE PLANE TRAJECTORIES OF THE MUSCLE SPIKE POTENTIAL. Biophys J. 1963 Sep;3:363–377. doi: 10.1016/s0006-3495(63)86827-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
- KATZ B. Depolarization of sensory terminals and the initiation of impulses in the muscle spindle. J Physiol. 1950 Oct 16;111(3-4):261–282. doi: 10.1113/jphysiol.1950.sp004479. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lindemann B., Thorns U. Fast potential spike of frog skin generated at the outer surface of the epithelium. Science. 1967 Dec 15;158(3807):1473–1477. doi: 10.1126/science.158.3807.1473. [DOI] [PubMed] [Google Scholar]
- REUBEN J. P., WERMAN R., GRUNDFEST H. The ionic mechanisms of hyperpolarizing responses in lobster muscle fibers. J Gen Physiol. 1961 Nov;45:243–265. doi: 10.1085/jgp.45.2.243. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sibaoka T., Eckert R. An electrophysiological study of the tentacle-regulating potentials in Noctiluca. J Exp Biol. 1967 Dec;47(3):447–459. doi: 10.1242/jeb.47.3.447. [DOI] [PubMed] [Google Scholar]