Summary
Pinealocyte ultrastructure has been studied in four sterile, four pregnant and three fertile but non-pregnant females, and also in three reproductively active male pigmented Duncan Hartley guinea pigs. Synaptic ribbons are dense, rod-like structures with a linear arrangement of clear vesicles periodically spaced on both sides of the rodlet. Although these structures were observed in the pinealocytes of all of the animals studied, they were scarce and difficult to locate in tissue from the fertile, non-pregnant females and from the reproductively active males. They were numerous in the pineal glands of the pregnant and sterile females. Typically they lie perpendicular to the cell membrane of the pinealocyte polar process and in close proximity to a polar process of a neighboring cell. The increased incidence of synaptic ribbons in pinealocytes which appear to be in a heightened state of activity strongly suggests a function for this structure. Synaptic ribbons are also present in sensory systems such as rods and cones of the retina, hair cells of the organ of Corti and hair cells of the vestibular apparatus. This fact, plus the photoreceptor function of pinealocytes in lower vertebrates, lends credence to the possibility that this structure may serve a sensory or receptor function in the guinea pig gland.
Similar content being viewed by others
References
Arstila, A. U. Electron microscopic studies on the structure and histochemistry of the pineal gland of the rat. Neuroendocrinology, Suppl.2, 1–101 (1967).
Draper, R. L. The prenatal growth of the guinea-pig. Anat. Rec.18, 369–392 (1920).
Hopsu, V. K., Arstila, A. U. An apparent somato-somatic synaptic structure in the pineal gland of the rat. Exp. Cell Res.37, 484–487 (1964).
Karasek, M. Quantitative changes in number of “synaptic” ribbons in rat pinealocytes after orchidectomy and in organ culture. J. Neural Transm.38, 149–157 (1976).
Kolmer, W., Loewy, R. Beiträge zur Physiologie der Zirbeldrüse. Pflügers Arch. Ges. Physiol.196, 1–14 (1922).
Krapp, C. The ependyma on the pineal of the guinea pig (Cavia cobaya). Anat. Embrol.152, 217–222 (1978).
Kurumado, K., Mori, W. Synaptic ribbon in the human pinealocyte. Acta Path. Jap.26, 381–384 (1976).
Ladman, A. J. The structure of the rod-bipolar cell synapse in the retina of the albino rat. J. Biophys. Biochem. Cytol.4, 459–466 (1958).
Lerner, A. B., Case, J. D., Heinzelman, R. V. Structure of melatonin. J. Amer. Chem. Soc.81, 6084 (1959).
Lues, G. Die Feinstruktur der Zirbeldrüse normaler, trächtiger und experimentell beeinflußter Meerschweinchen. Z. Zellforsch.114, 38–60 (1971).
Miline, R., Devecerski, V., Sijacki, N., Krstic, R. Pineal gland behavior as affected by cold. Hormones1, 321–331 (1970).
Pevet, P., Ariëns Kappers, J., Voute, A. M. Morphologic evidence for differentiation of pinealocytes from photoreceptor cells in the adult noctule bat (Nyctalus noctula, Schreiber). Cell Tissue Res.182, 99–109 (1977).
Quay, W. B. Pineal blood content and its experimental modification. Amer. J. Physiol.195, 391 (1958).
Sjöstrand, F. S. Ultrastructure of retinal rod synapses of the guinea-pig eye as revealed by three-dimensional reconstructions from serial sections. J. Ultrastruct. Res.2, 122–170 (1958).
Vollrath, L. Light and dark induced changes of epiphysial synaptic ribbons. Cell Tissue Res.165, 383–390 (1976).
Vollrath, L., Huss, H. The synaptic ribbons of the guinea pig pineal gland under normal and experimental conditions. Z. Zellforsch.139, 417–429 (1973).
Wartenberg, H. The mammalian pineal organ: Electron microscopic studies on the fine structure of pinealocytes, glial cells and on the perivascular compartment. Z. Zellforsch.86, 74–97 (1968).
Wolfe, D. E. The epiphyseal cell: An electron microscopic study of its intercellular relationships and intracellular morphology in the pineal body of the albino rat. Prog. Brain Res.10, 332–386 (1965).
Zimmerman, B. L., Tso, M. O. M. Morphologic evidence of photoreceptor differentiation of pinealocytes in the neonatal rat. J. Cell Biology66, 60–75 (1975).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
McNeill, M.E., Whitehead, D.S. The synaptic ribbons of the guinea pig pineal gland in sterile, pregnant and fertile but non-pregnant females and in reproductively active males. J. Neural Transmission 45, 149–164 (1979). https://doi.org/10.1007/BF01250090
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF01250090