Summary
The photoreceptors of the planarian Dugesia dorotocephala were studied by light microscopy and electron microscopy. The eye was found to be rhabdomeric; it is composed of approximately 25 visual cells and a monolayered cup of pigment cells enclosing the light sensitive rhabdome. The pigment cell gave the appearance of having a phagocytic function in addition to regulating the light entering the rhabdome. Extensions of these pigment cells were shown to be the “membranous structure” seen by light microscopy in the open area of the eye. The bipolar visual cell consisted of a perikaryon, axon and a dendritic extension comprised of a stalk, conical body and microvillous rhabdomere. Efferent nerve fibers formed synapses with dendritic spines protruding from receptor stalks. A specialized structure at the transition area between neurotubules and neurofilaments was observed in the conical body. A dense intercellular space occurred between all regions of adjoining visual cells.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Brown, H. M.: Some characteristics of the light-evoked electrical response of the planarian eyecup. In: Chemistry of learning, W. C. Corning and S. C. Ratner, ed., p. 164–165. New York: Plenum Press 1967
Brown, H. M., Ogden, T. E.: Some characteristics of electrical activity evoked in the eyecup of the planarian Dugesia tigrina. Physiologist 8, 124 (1965)
Brown, H. M., Ogden, T. E.: Electrical response of the planarian eyecup in different states of light adaptation. Physiologist 9, 145 (1966)
Carpenter, K. S., Morita, M.: Changes in light and dark adapted planarian photoreceptors. Proc. 30th Ann. EMSA 42–43 (1972)
Carpenter, K. S., Morita, M., Best, J. B.: Ultrastructure of the photoreceptor of the planarian Dugesia dorotocephala. II. Changes induced by darkness and light. Cytobiologie (In press) 1974
Clark, A. W., Millecchia, R., Mauro, A.: The ventral photoreceptor cells of Limulus. I. The microanatomy. J. gen. Physiol. 54, 289–309 (1969)
Curtis, D. J.: The fine structure of photoreceptors in Mitopus morio (Phalangida). J. Cell Sci. 4, 327–351 (1969)
Eakin, R. M.: Lines of evolution of photoreceptors. In: General physiology of cell specialization D. Mazia and A. Tyler, eds. New York: McGraw-Hill Book Co. 1963
Eakin, R. M.: Evolution of photoreceptors. In: Evolutionary biology II. T. Dobzhansky, M. K. Hecht and W. C. Steere, eds. New York: Appleton-Century-Crofts 1968
Eakin, R. M., Brandenburger, J. L.: Localization of vitamin A in the eye of a pulmonate snail Proc. nat. Acad. Sci. (Wash.) 60, 141–145 (1968)
Eakin, R. M., Kuda, A.: Ultrastructure of sensory receptors in ascidian tadpoles. Z. Zellforsch. 112, 287 (1971)
Eguchi, E., Waterman, T. H.: Changes in retinal fine structure induced in the crab, Libidina, by light and dark adaptation. Z. Zellforsch. 79, 209–229 (1967)
Eguchi, E., Waterman, T. H.: Cellular basis for polarized light perception in the spidercrab, Libidina. Z. Zellforsch. 84, 87–101 (1968)
Fahrenbach, W. H.: The fine structure of a Nauplius eye. Z. Zellforsch. 62, 182–197 (1964)
Fahrenbach, W. H.: The morphology of the eyes of Limulus II. Z. Zellforsch. 93, 451–483 (1969)
Fahrenbach, W. H.: The morphology of the Limulus visual system III. Z. Zellforsch. 105, 303–316 (1970)
Ishikawa, T., Yamada, E.: The degradation of the photoreceptor outer segment within the pigment epithelial cell of rat retina. J. Elec. Micros. 19, 85–91 (1970)
Kishida, Y.: Electron microscopy studies on the planarian eye I. Sci. Rep. Kanazawa Univ. 12. 75–110 (1967a)
Kishida, Y.: Electron microscopy studies on the planarian eye II. Sci. Rep. Kanazawa Univ. 12, 111–142 (1967b)
Lasansky, A.: Cell junctions in Ommatidia of Limulus. J. Cell Biol. 33, 365–383 (1967)
Loewenstein, W. R., Kanno, Y.: Studies on the epithelial (T) gland cell function. I. Modifications of surface membrane permeability. J. Cell Biol. 22, 565 (1964)
MacRae, E. K.: Observations on the fine structure of photoreceptor cells in the planarian Dugesia tigrina. J. Ultrastruct. Res. 10, 334–349 (1964)
MacRae, E. K.: Fine structure of photoreceptors in a marine flatworm. Amer. Zool. 5, 247 (1966a)
MacRae, E. K.: The fine structure of photoreceptors in a marine flatworm. Z. Zellforsch. 75, 469–484 (1966b)
Melamed, J., Trujillo-Cenóz, O.: The fine structure of the visual system of Lycosa. I. Z. Zellforsch. 74, 12–31 (1966)
Morita, M., Best, J. B.: In preparation. Electron microscopic studies of planarian regeneration. III. Observations on the Blastema formation in Dugesia dorotocephala. In preparation
Morita, M., Best, J. B., Noel, J.: Electron microscopic studies of planarian regeneration. I. Fine structure of neoblasts in Dugesia dorotocephala. J. Ultrastruct. Res. 27, 7–23 (1969)
Perrelet, A.: The fine structure of the retina of the honeybee drone. Z. Zellforsch. 108, 530–562 (1970)
Perry, M. M.: Further studies on the development of the eye of Dorosophila melanogaster I. J. Morph. 124, 227–247 (1968)
Pigon, A., Morita, M., Best, J. B.: Cephalic mechanism for social control of fissioning in planarians. II. Localization and identification of the receptors by electron micrographic and ablation studies. Jour. Neurobiol. (In press) (1974)
Press, N.: Electron microscopy study of the distal portion of a planarian retinula cell. Biol. Bull. 117, 511–517 (1959)
Reynolds, E. S.: The use of lead citrate at high pH as an electron-opaque stain in electron microscopy. J. Cell Biol. 17, 208–213 (1963)
Röhlich, P.: Sensitivity of regeneration and degenerating planarian photoreceptors to osmium fixation. Z. Zellforsch. 73, 165–173 (1966)
Röhlich, P., Török, L. J.: Elektronenmikroskopische Untersuchungen des Auges von Planarien. Z. Zellforsch. 54, 362–381 (1981)
Schmitt, F. O., Samson, F. E. Jr.: Neuronal fibrous proteins; a review based on two NRP conferences. Neurosciences Research Program Bulletin 6, 113–219 (1968)
Stewart, A.: Ultrastructure of the eyes in three freshwater triclad worms. Amer. Zool. 6, 615–616 (1966)
Tasaki, K., Karita, K.: Discrimination of horizontal and vertical planes of polarized light by the cephalopod retina. Jap. J. Physiol. 16, 205–216 (1966)
Thurm, U.: General organization of sensory receptors, p. 44–68. In: Proceedings of the International School of Physics Course XLIII. W. Reichardt, ed. New York: Academic Press (1969)
Tonosaki, A.: Fine structure of the retina in Haliotis discus. Z. Zellforsch. 79, 469–480 (1967)
Varela, F. G., Porter, K. R.: Fine structure of the visual system of the honeybee. I. The retina. J. Ultrastruct. Res. 29, 236–259 (1969)
Young, R. W.: The renewal of photoreceptor cell outer segments. J. Cell Biol. 33, 61–72 (1967)
Young, R. W.: The renewal of rod and cone outer segments in the Rhesus Monkey. J. Cell Biol. 49, 303–318 (1971)
Author information
Authors and Affiliations
Additional information
This work was supported by National Institute of Mental Health Grant Number 2 R01-MH07603 and General Research Support Grant 5 S01-RR05458-9 given to the Dean of the College of Veterinary Medicine and Biomedical Sciences, Colorado State University.
The authors wish to acknowledge the valuable technical assistance of Les Brown in these studies.
Rights and permissions
About this article
Cite this article
Carpenter, K.S., Morita, M. & Best, J.B. Ultrastructure of the photoreceptor of the planarian Dugesia dorotocephala . Cell Tissue Res. 148, 143–158 (1974). https://doi.org/10.1007/BF00224579
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00224579