Summary
Electron microscopy was employed in a study of the pineal gland of the Mongolian gerbil (Meriones unguiculatus). It was determined that the gerbil pineal gland contains pinealocytes and glial cells with the pinealocytes being the predominant cell type. The pinealocytes contain numerous organelles traditionally considered as being either synthetic or secretory in function such as an extensive Golgi region, smooth (SER) and rough (RER) endoplasmic reticulum, secretory vesicles and microtubules. Other cytoplasmic components are also present in the pinealocytes (synaptic ribbons, subsurface cisternae) for which no function has been assigned. Dense-cored vesicles are rare. Vacuolated pinealocytes are present and appear to be intimately associated with the formation of the pineal concertions. Evidence presented supports the proposal that the concretions form within the vacuoles. Once the concretions reach an enlarged state, the vacuolated pinealocytes break down and the concretions are thus extruded into the extracellular space where they apparently continue to increase in size. The morphology of the glial cells was interpreted as indicative of a high synthetic activity. The glial cells contain predominantly the rough variety of endoplasmic reticulum and form an expansion around the wide perivascular area.
Similar content being viewed by others
References
Blitz, A.L., Fine, R.E., Toselli, P.A.: Evidence that coated vesicles isolated from brain are calcium-sequestering organelles resembling sarcoplasmic reticulum. J. Cell Biol. 75, 135–147 (1977)
Clabough, J.: Ultrastructural features of the pineal gland in normal and light deprived golden hamsters. Z. Zellforsch. 114, 151–164 (1971)
Gregorek, J.C.: The ultrastructure of the pineal gland of normal and enucleated gerbils. Anat. Rec. 175, 333 (1973)
Hopsu, V.K., Arstila, A.U.: An apparent somato-somatic synaptic structure in the pineal gland of the rat. Exp. Cell Res. 35, 484–487 (1964)
Ito, T., Matsushima, S.: Electron microscopic observations on the mouse pineal, with particular emphasis on its secretory nature. Arch. histol. jap. 30, 2–15 (1968)
Japha, J.L., Eder, T.J., Goldsmith, E.D.: Calcified inclusions in the superficial pineal gland of the Mongolian gerbil, Meriones unguiculatus. Acta anat. (Basel) 95, 533–544 (1976)
Japha, J.L., Eder, T.J., Goldsmith, E.D.: A histochemical study of aldehyde fuchsin-positive material and “high-esterase cells” in the pineal gland of the Mongolian gerbil. Amer. J. Anat. 149, 23–38 (1977)
Karasek, M.: Quantitative changes in number of “synaptic” ribbons in rat pinealocytes after orchidectomy and in organ culture. J. Neural Trans. 38, 149–157 (1976)
Karnovsky, M.J.: A formaldehyde glutaraldehyde fixative of high osmolality for use in electron microscopy. J. Cell Biol. 27, 137A (1965)
Karnovsky, M.J.: Use of ferrocyanide-reduced osmium tetroxidein electron microscopy. Abs. Am. Soc. Cell Biol., p. 146 (1971)
Krstic, R.: Ultracytochemistry of the synaptic ribbons in the rat pineal organ. Cell Tiss. Res. 166, 135–143 (1976)
Krstic, R., Golaz, J.: Ultrastructural and X-ray microprobe comparison of gerbil and human pineal acervuli. Experientia (Basel) 33, 507–508 (1977)
Lin, H.-S.: Transformation of centrioles in pinealocytes of adult guinea pigs. J. Neurocytology 1, 61–68 (1972)
Lukaszyk, A., Reiter, R.J.: Histophysiological evidence for the secretion of polypeptides by the pineal gland. Amer. J. Anat. 143, 451–464 (1975)
Matsushima, S., Reiter, R.J.: Ultrastructural observations of pineal gland capillaries in four rodent species. Amer. J. Anat. 143, 265–281 (1975a)
Matsushima, S., Reiter, R.J.: Comparative ultrastructural studies of the pineal gland of rodents. In: Electron microscopic concepts of secretion: Ultrastructure of endocrine and reproductive organs (Hess, M., ed.), pp. 335–356. New York: Wiley 1975b
Møller, M.: The ultrastructure of the human fetal pineal gland. I. Cell types and blood vessels. Cell Tiss. Res. 152, 13–30 (1974)
Oksche, A.: Sensory and glandular elements of the pineal organ. In: The pineal gland (Wolstenholme, G.E.W. and Knight, J., eds.), pp. 127–146. Edinburgh-London: Churchill Livingstone 1971
Pevet, P.: The pineal gland of the mole (Talpa europaea L.). I. The fine structure of the pinealocytes. Cell Tiss. Res. 153, 277–292 (1974)
Pevet, P.: Correlations between pineal gland and sexual cycle. An electron microscopical and histochemical investigation on the pineal gland of the hedgehog, mole, mole-rat and white rat. Amsterdam: Thesis 1976
Pevet, P.: On the presence of different populations of pinealocytes in the mammalian pineal gland. J. Neural Trans. 40, 289–304 (1977)
Pevet, P., Ariëns Kappers, J., Voute, A.M.: The pineal gland of nocturnal mammals. I. The pinealocytes of the bat (Nyctalus noctula, Schreber). J. Neural Trans. 40, 47–68 (1977)
Reinharz, A.C., Vallotton, M.B.: Presence of two neurophysins in the human pineal gland. Endocrin. 100, 994–1001 (1977)
Reiter, R.J.: Comparative physiology: pineal gland. Ann. Rev. Physiol. 35, 305–328 (1973)
Reiter, R.J., Welsh, M.G., Vaughan, M.K.: Age-related changes in the intact and sympathetically denervated gerbil pineal gland. Amer. J. Anat. 146, 427–432 (1976)
Reynolds, E.S.: The use of lead citrate at high pH as an electron-opaque stain in electron microscopy. J. Cell Biol. 17, 208–212 (1963)
Rodin, A.E., Turner, R.A.: The perivascular space of the pineal gland. Tex. Rep. Biol. Med. 24, 153–163 (1966)
Romijn, H.J.: Structure and innervation of the pineal gland of the rabbit, Oryctolagus cuniculus (L.). II. An electron microscopic investigation of the pinealocytes. Z. Zellforsch. 141, 545–560 (1973)
Sheridan, M.N.: Pineal gland fine structure: Dense-cored vesicles. In: Brain-endocrine interaction. The ventricular system in neuroendocrine mechanisms (K.M. Knigge, D.E. Scott, H. Kobayashi, S. Ishii, eds.) Basel: Karger 1975
Sheridan, M.N., Reiter, R.J.: The fine structure of the pineal gland in the pocket gopher (Geomys bursarius L.). Amer. J. Anat. 135, 363–382 (1973)
Sheridan, M.N., Sladek, J.R., Jr.: Histofluorescence and ultrastructural analysis of hamster and monkey pineal. Cell Tiss. Res. 164, 145–152 (1975)
Spurr, A.R.: A low-viscosity epoxy resin embedding medium for electron microscopy. J. Ultrastruct. Res. 26, 31–43 (1969)
Thorn, N.A.: Cellular transport of calcium. Calcium transport processes and their regulation in endocrine cells. In: Calcified tissues (S. Pors Nielsen and E. Hjørting-Hansen, eds.) Copenhagen: Fadl 1976
Trump, B.F., Bulger, R.E.: New ultrastructural characteristics of cells fixed in a glutaraldehyde-osmium tetroxide mixture. Lab. Invest. 15, 368–379 (1969)
Vollrath, L.: Synaptic ribbons of a mammalian pineal gland circadian changes Z. Zellforsch. 145, 171–183 (1973)
Welsh, M.G., Reiter, R.J.: The ultrastructure of the gerbil pineal gland under normal and experimental conditions. Proc. Electron Microsc. Soc. Amer., 34th Ann. Mtg., pp. 122–123 (1976)
Wolfe, D.E.: The epiphysial cell: an electron-microscopic study of its intercellular relationships and intracellular morphology in the pineal body of the albino rat. Prog. Brain Res. 10, 332–376 (1965)
Author information
Authors and Affiliations
Additional information
Supported by NSF grant PCM 77-05734
Rights and permissions
About this article
Cite this article
Welsh, M.G., Reiter, R.J. The pineal gland of the gerbil, Meriones unguiculatus . Cell Tissue Res. 193, 323–336 (1978). https://doi.org/10.1007/BF00209044
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00209044