Abstract
Removing the glial cells that encase Limulus ventral photoreceptors allows direct observation of the cell surface. Light microscopy of denuded photoreceptors reveals a subdivision of the cell body into lobes. Often one lobe, but sometimes several, is relatively clear and translucent (the R lobes). The lobe adjacent to the axon (the A lobe) has a textured appearance. Scanning electron microscopy shows that microvilli cover the surface of R lobes and are absent from the surface of A lobes. When a dim spot of light is incident on the R lobe, the probability of evoking a single photon response is two to three orders of magnitude higher than when the same spot is incident on the A lobe. We conclude that the sensitivity of the cell to light is principally a function of the R lobe.
Full Text
The Full Text of this article is available as a PDF (2.8 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Brown J. E., Harary H. H., Waggoner A. Isopotentiality and an optical determination of series resistance in Limulus ventral photoreceptors. J Physiol. 1979 Nov;296:357–372. doi: 10.1113/jphysiol.1979.sp013010. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Clark A. W., Millecchia R., Mauro A. The ventral photoreceptor cells of Limulus. I. The microanatomy. J Gen Physiol. 1969 Sep;54(3):289–309. doi: 10.1085/jgp.54.3.289. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Coles J. A., Tsacopoulos M. Ionic and possible metabolic interactions between sensory neurones and glial cells in the retina of the honeybee drone. J Exp Biol. 1981 Dec;95:75–92. doi: 10.1242/jeb.95.1.75. [DOI] [PubMed] [Google Scholar]
- Dodge F. A., Jr, Knight B. W., Toyoda J. Voltage noise in Limulus visual cells. Science. 1968 Apr 5;160(3823):88–90. doi: 10.1126/science.160.3823.88. [DOI] [PubMed] [Google Scholar]
- FUORTES M. G., YEANDLE S. PROBABILITY OF OCCURRENCE OF DISCRETE POTENTIAL WAVES IN THE EYE OF LIMULUS. J Gen Physiol. 1964 Jan;47:443–463. doi: 10.1085/jgp.47.3.443. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fain G. L., Lisman J. E. Membrane conductances of photoreceptors. Prog Biophys Mol Biol. 1981;37(2):91–147. doi: 10.1016/0079-6107(82)90021-9. [DOI] [PubMed] [Google Scholar]
- Fein A., Charlton J. S. Local adaptation in the ventral photoreceptors of Limulus. J Gen Physiol. 1975 Dec;66(6):823–836. doi: 10.1085/jgp.66.6.823. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fein A., Charlton J. S. Local membrane current in Limulus photoreceptors. Nature. 1975 Nov 20;258(5532):250–252. doi: 10.1038/258250a0. [DOI] [PubMed] [Google Scholar]
- Fein A., Lisman J. Localized desensitization of Limulus photoreceptors produced by light or intracellular calcium ion injection. Science. 1975 Mar 21;187(4181):1094–1096. doi: 10.1126/science.1114339. [DOI] [PubMed] [Google Scholar]
- Lasek R. J., Tytell M. A. Macromolecular transfer from glia to the axon. J Exp Biol. 1981 Dec;95:153–165. doi: 10.1242/jeb.95.1.153. [DOI] [PubMed] [Google Scholar]
- Lisman J. E., Brown J. E. Effects of intracellular injection of calcium buffers on light adaptation in Limulus ventral photoreceptors. J Gen Physiol. 1975 Oct;66(4):489–506. doi: 10.1085/jgp.66.4.489. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lisman J. E., Brown J. E. The effects of intracellular iontophoretic injection of calcium and sodium ions on the light response of Limulus ventral photoreceptors. J Gen Physiol. 1972 Jun;59(6):701–719. doi: 10.1085/jgp.59.6.701. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Waterman T. H., Pooley A. S. Crustacean eye fine structure seen with scanning electron microscopy. Science. 1980 Jul 11;209(4453):235–240. doi: 10.1126/science.209.4453.235. [DOI] [PubMed] [Google Scholar]