Showing papers on "Pinealocyte published in 1977"
TL;DR: The different categories of cells described by many authors in the pineal gland of mammals have been critically considered and secretory processes present in some mammalian species, including the mole, the hedgehog, and the rat, are considered.
Abstract: The different categories of cells described by many authors in the pineal gland of mammals have been critically considered. In some mammalian species, two different populations of pinealocytes have been observed. To each of these populations a specific secretory process can be attributed. One is characterized by the formation of granular vesicles originating from the Golgi apparatus, the other by the formation of material directly from the cisterns of the granular endoplasmic reticulum. Both of these secretory processes appear to be also present in the pineal of the mole, the hedgehog, and the rat, mammals in which generally only one population of pinealocytes has been described. The physiological consequences of these findings have been discussed.
90 citations
TL;DR: In this article, the number of dense-cored or granulated vesicles present in the polar terminals of pinealocytes were quantitated in thin cross sections through pericapillary areas.
Abstract: Adult, Charles River CD-1, male mice were housed in an environmental control chamber under strict conditions of controlled light (12D/12L) and temperature. The mice were sacrificed at various times throughout the twenty-four hour clock and their pineals prepared routinely for electron microscopy. The number of dense-cored or granulated vesicles present in the polar terminals of pinealocytes were quantitated in thin cross sections through pericapillary areas. A distinct circadian rhythm was observed in the number of granulated vesicles with a three- to four-fold difference between late photoperiod maximum and late dark period minimum. The rhythm was abolished by bilateral superior cervical ganglionectomy. These results are consistent with the hypothesis that the granulated vesicles are synthesized and stored in the pinealocytic cytoplasm during the photoperiod under the tropic influence of norepinephrine, and are released during the dark period when melatonin synthesis is greatest. Melatonin, administered as daily intraperitoneal doses of 50 μg over a period of five days, was observed to increase markedly the number of pinealocytic granulated vesicles during the light period, but led during the dark period to a decrease in their numbers to levels below that of diluent-treated controls. It may be that melatonin stimulates the synthesis and/or release of granulated vesicles which represent the packaged form of a major secretory product.
68 citations
TL;DR: The data from cytologically pineal glands taken from rats seem to confirm a circadian function in the pineal gland in mammals, and are similar to those of Vollrath from the pineapple gland of a guinea pig.
Abstract: To seek a morphological expression of circadian rhythm, we investigated cytologically pineal glands taken from rats every 2 to 4 h under a lighting regime of 12 h of illumination (6:00 to 18:00) and 12h of darkness. The changes in the number of synaptic ribbons and ribbon fields was observed by electron microscopy. The number of these intracellular elements was greatest at 2:00 and lowest at 14:00, the difference being statistically significant. There were no significant local differences in numbers with respect to the part of the pineal gland examined. The data are similar to those of Vollrath from the pineal gland of a guinea pig, and seem to confirm a circadian function in the pineal gland in mammals.
64 citations
49 citations
TL;DR: The ultrastructure of the pinealocytes of noctule bats, mammals which live most of the time in darkness or very low light intensities, was examined and compared with the pineAlocytes of other mammals.
Abstract: The ultrastructure of the pinealocytes of noctule bats, mammals which live most of the time in darkness or very low light intensities, was examined and compared with the pinealocytes of other mammals. Two different populations of pinealocytes (I and II) were observed. They differ in general aspect, in location and especially in their content of cell organelles involved in synthetic processes. Mitochondria, ribosomes, lysosomes and lipid inclusions were present in the perikaryon of pinealocytes of both populations. In the pinealocytes of population I some granular vesicles, of presumed Golgi origin, and some other structures were observed. Pinealocytes of population II are characterized by many glycogen granules, more or less associated with a large vacuolar system. Moreover, some small vacuoles originating from cisterns of the granular endoplasmic reticulum and containing flocculent material of a moderate electron density are described. The possibility is discussed that these small vacuoles are involved in one of the secretory processes of the pineal gland while the granular vesicles of the pinealocyte of the population I are the products of another.
48 citations
TL;DR: An attempt was made to demonstrate melatonin in the rat pineal gland by means of immunohistochemistry, and specific fluorescence was demonstrable only in pineals from rats killed during the night, when melatonin formation is high.
Abstract: In the present study an attempt was made to demonstrate melatonin in the rat pineal gland by means of immunohistochemistry. The anti-body used was raised against 5-methoxy-N-acetyltryptophan which is chemically similar to melatonin. Specific fluorescence was demonstrable only in pineals from rats killed during the night, when melatonin formation is high. It was restricted to parenchymal cells lying in a marginal zone of the organ. These results are discussed in relation to a subdivision of the pineal parenchyma into cortical and medullary areas.
39 citations
TL;DR: An electron microscopical investigation of the pineal gland of the adult noctule bat revealed the presence of some peculiar ciliary derivatives, similar to the club-shaped outer segment of rudimentary photoreceptor cells in the Pineal organ of nonmammalian vertebrates, which reconfirm the concept of the sensory cell line in the vertebrate pineal organ.
Abstract: An electron microscopical investigation of the pineal gland of the adult noctule bat revealed the presence of some peculiar ciliary derivatives, similar to the club-shaped outer segment of rudimentary photoreceptor cells in the pineal organ of nonmammalian vertebrates. The pinealocytes of population I can be classified in several morphological types, one of them displaying morphological features resembling those of rudimentary photoreceptor cells. These results reconfirm the concept of the sensory cell line in the vertebrate pineal organ. The question whether the pinealocytes of population II belong to the same sensory cell line is discussed.
35 citations
TL;DR: The pineal cell cultures were able to support the growth of dispersed cells of rat superior cervical ganglia and to allow neurite outgrowth in these co-cultures, though the presence of nerve growth factor (NGF) in the medium of these cultures could not be detected.
34 citations
TL;DR: Frequency distribution histograms of diameters of granulated and non-granulated vesicles in the adrenergic nerve endings demonstrate that the pineal nerve endings in the chinchilla contain a considerable number of large granulation andNon-granulation vesicle, in contrast to those in the rat and ground squirrel.
Abstract: The ultrastructural features of the adrenergic nerve fibers in the pineal glands of the rat, ground squirrel and chinchilla are described. Frequency distribution histograms of diameters of granulated and non-granulated vesicles in the adrenergic nerve endings demonstrate that the pineal nerve endings in the chinchilla contain a considerable number of large granulated and non-granulated vesicles, in contrast to those in the rat and ground squirrel. Synaptic ribbons seen in the pinealocytes of the ground squirrel were often localized near that plasma membrane which lay in close proximity to the axolemma of adrenergic nerve fibers. This observation may indicate that the synaptic ribbons are involved in the functional interconnection between pinealocytes and adrenergic nerve fibers. Localized dilations of the adrenergic nerve fibers were commonly observed in the pineal glands of all species examined. In addition to a variety of axonal constituents, various forms of inclusion bodies were tightly packed within these axonal dilations. The accumulation of the inclusion bodies may represent degenerative changes which occur in the pineal adrenergic nerve fibers in relation to the functional activity of the pineal gland.
32 citations
TL;DR: The effect of a proteolytic enzyme, pronase, on material present in cisternae of the granular endoplasmic reticulum of mole pinealocytes demonstrates their proteinaceous nature.
Abstract: The effect of a proteolytic enzyme, pronase, on material present in cisternae of the granular endoplasmic reticulum of mole pinealocytes demonstrates their proteinaceous nature.
30 citations
TL;DR: Evidence that secretory activity is maintained from embryonic stages to adulthood is provided and dense core vesicles are located both around the Golgi apparatus and in the basal process.
Abstract: The pineal organ of the chicken was investigated electron microscopically during embryonic and post-hatching development with special regard to photosensory and secretory features. Throughout the developmental period both pinealocytes and supporting cells, of which the pineal parenchyma is composed, were rich in ribosomes, granular endoplasmic reticulum and mitochondria, but lacked agranular endoplasmic reticulum. The outer segments of pinealocytes barely showed formation of lamellar structures (disks) at the 17th and 21st day of incubation. Before and after hatching the follicular lumen was often filled with amorphous material presumed to be derived from outer or inner segments. By 15 days after hatching the whorl-like structures were occasionally connected to bulbous outer segments, and their relation appeared similar to that of the adult. Mitochondria disappeared from the inner segments after 21 days of incubation. Dense core vesicles (about 80–120 nm in diameter), regarded as secretory granules, appeared first at the 10th day of incubation in the supranuclear region of the pinealocyte. With the extending of basal processes the dense core vesicles gradually migrated into these processes, attained maximum number one month after hatching and increased further in the adult; they are located both around the Golgi apparatus and in the basal process. These results provide evidence that secretory activity is maintained from embryonic stages to adulthood.
TL;DR: The apparent stimulation of pinealocytic organelles coupled with the observed decrease in dense-cored vesicles suggest an increased synthesis and release of secretory product.
Abstract: The mammalian pineal is thought to produce an antigonadotropic principle under conditions of reduced photoperiod, constant darkness or blinding by optic enucleation. A number of previous studies on mammalian pineals have suggested that the dense-cored vesicles present in pinealocytes may represent morphological evidence of secretory activity. In the present study the ultrastructure of pinealocytes was studied in adult Charles River CD-1 mice blinded by optical enucleation. By one month following optic enucleation the mean number of dense-cored vesicles in the cytoplasm of pinealocytes adjacent to pericapillary spaces had significantly decreased by 55% when compared with intact controls, and remained at this low level at two months and six months. A relative increase in the proportion of large agranular vesicles and an increased number of large, irregular vacuoles was observed also in the pinealocytic polar processes of blinded mice. When compared to control mice the pinealocytic Golgi regions appeared to be hypertrophied in blinded mice. The apparent stimulation of pinealocytic organelles coupled with the observed decrease in dense-cored vesicles suggest an increased synthesis and release of secretory product.
TL;DR: The pineal organ provides the animal with a "biological clock", which is geared to the lighting environment, which converts a light input (direct in lower vertebrates, via transmitter release by sympathetic fibers in mammals) into a hormonal output.
Abstract: The pineal complex develops from a tubular evagination of the diencephalic roof. In amphibians a proliferation zone is the source of the pinealocytes and of the cells of the subcommissural organ. The pinealocytes are not real nerve cells, but derived likewise from the embryonic neural epithelium. The pinealocytes of lower vertebrates are directly photosensitive; however, the morphological structures for direct light perception are gradually lost in the phylogenetic development and are absent in the pinealocytes of mammals. A secretory function is shown in the pinealocytes of all vertebrates, but it is more pronounced in the pinealocytes of reptiles, birds and mammals; dense-cored vesicles originate in the Golgi complex and are transported to and accumulated in the terminals of the basal processes near the perivascular space. Nerve cells are in synaptic ribbon contact with pinealocytes in lower vertebrates and their axons give a rise to the tractus pinealis. The nerve cells and nervous connection with the brain are absent in the pineal organ of mammals. Only few autonomic fibers reach the pineal organ of lower vertebrates, but the sympathetic and parasympathetic innervation are well developed in the pineal organ of most species of birds and mammals. The transmitter release from the sympathetic fibers is influenced by environmental light; light mediates in this way the activity of hormone producing enzymes in the pinealocytes. The synthesis of indolderivates, like melatonin, is confirmed and the presence of a polypeptide hormone is discussed. Accordingly, the pineal organ functions as a "neuro" chemical, "neuro" endocrine transducer or photo-"neuro" endocrine organ, which converts a light input (direct in lower vertebrates, via transmitter release by sympathetic fibers in mammals) into a hormonal output. The pineal organ thus provides the animal with a "biological clock", which is geared to the lighting environment. The pineal organ is a regulator (or a regulator of regulators) for several body functions. In mammals, the influence on the synchronization of the gonadal activity is best known. The pinealocyte is a hormone producing cell, which shows common features with the liquor contacting neurons and with the neurosecretory cells; after the definition of FUJITA (1976) the pinealocyte is said to be a paraneuron, also.
TL;DR: It is suggested that the synthesis and storage of indoleamines in the rabbit pineal gland do not take place within the conventional membrane-limited cell organelles but more diffusely in the cytosol of the light pinealocytes.
Abstract: In order to localize pineal indoleamine synthesis at the ultrastructural level, an electron microscopic analysis was carried out on rabbit pineal tissue, cultured for several days in a medium containing the inhibitor p-chlorophenylalanine. Furthermore, electron microscopic autoradiography was applied to rabbit pineal tissue cultured in a medium containing the tritium labeled precursor 5-hydroxytryptophan. p-Chlorophenylalanine altered the ultrastructure of the mitochondria in the light pinealocytes only. Incubation with 3H-5-hydroxytryptophan caused a moderate and uniform labeling of the pinealocytes. These data suggest that the synthesis and storage of indoleamines in the rabbit pineal gland do not take place within the conventional membrane-limited cell organelles but more diffusely in the cytosol of the light pinealocytes.
TL;DR: Electron microscopic evidence is given that the small dark granules in the rabbit dark pinealocytes represent glycogen, which is synthesized at the membranes of the rough endoplasmic reticulum to participate then in the conversion of the lysosomes into pigment bodies.
Abstract: Electron microscopic evidence is given that the small dark granules in the rabbit dark pinealocytes represent glycogen. The conception is put forward that this glycogen, synthesized at the membranes of the rough endoplasmic reticulum, is taken up by lysosomes to participate then in the conversion of the lysosomes into pigment bodies.
TL;DR: Staining with AF was markedly reduced after incubation with trypsin, indicating that the AF-positive material is at least partially protein, and it may be that the "high-esterase cells" contain AF- positive material.
Abstract: The pineal gland of the Mongolian gerbil consists of a superficial gland, stalk and deep pineal. The deep pineal differentiates postnatally. Histochemical studies of the superficial pineal gland indicate that it may be involved in the secretion of protein. Presumptive secretory material visualized by aldehyde fuchsin (AF) and chrome hematoxylin was observed along the course of blood vessels and among the pinealocytes. The distribution and texture of the AF-positive material was distinctive. It did not correspond to the pattern and texture of material stained with PAS, Sudan Black or acid orcein. Staining with AF was markedly reduced after incubation with trypsin, indicating that the AF-positive material is at least partially protein. The amount of stainable material increased with age. The AF-positive material was observed in what appeared to be interstitial or glial cells and processes, and in the processes of perivascular cells. Cells and fibrous processes with high non-specific esterase activity ("high-esterase cells") were observed among the pinealocytes and along the course of blood vessels. The distribution of the "high-esterase cells" and the morphology and texture of their esterase-containing processes were remarkably similar to the morphology and distribution of the material that stained with AF. It may be that the "high-esterase cells" contain AF-positive material. The "high-esterase cells" hydrolyzed both alpha-naphthyl acetate and alpha-naphthyl butyrate. The pinealocytes hydrolyzed only alpha-naphthyl acetate. The "high-esterase cells" appear to form a distinct class of cells within the superficial pineal gland. They are tentatively identified as a type of glial cell.
TL;DR: In this article, the number of small granulated vesicles (60nm in diameter) in the pineal gland of the mouse pineal was found to increase at night to reach the maximum level at the beginning of the light period of the day.
Abstract: Quantitative electron microscopic observations on the pineal gland of the mouse were made in order to demonstrate ultrastructural changes in response to various conditions of illumination in sympathetic nerve fibers as well as in pinealocytes and, thus, to establish some morphological correlates of a functional relationship between sympathetic nerves and pinealocytes. The diurnal change in the number of the small granulated vesicles (60nm in diameter) in sympathetic nerve fibers of the mouse pineal is similar to that of the noradrenaline content in the rat pineal; increasing at night to reach the maximum level at the beginning of the light period of the day. A marked decrease of the small granulated vesicles seen after the onset of darkness may be correlated with a release of noradrenaline from the nerve fibers. Since the diurnal change in the number of the granulated vesicles (100nm in diameter) and the glycogen content in the mouse pinealocytes closely resemble each other, the diurnal variation in the number of the granulated vesicles and the amount of glycogen may be influenced by a diurnal rhythm in the release of noradrenaline. The number of the granulated vesicles and the glycogen content in the pinealocytes show another striking similarity in that their remarkable increase is induced by continuous light for relatively short periods. It is speculated that light suppresses the release of noradrenaline from the nerve fibers and, thus, causes an increase of the glycogen content as well as the number of the granulated vesicles in the pinealocytes.
TL;DR: An apparent increase in the number of large mitochondria, membrane whorls and dense-cored secretory vesicles in pinealocytes of melatonin-treated hamsters suggests enhanced pineal gland activity.
Abstract: Weekly subcutaneous implants of melatonin in a beeswax pellet prevented the testicular regression which normally occurs in hamsters exposed to short photoperiod for 8 weeks Normal (14L:10D) hamster testes were indistinguishable from the testes of melatonin-treated (1L:23D) hamsters The exogenous melatonin had varied effects on the fine structure of the golden hamster pineal gland Pinealocyte nuclear characteristics of melatonin-treated hamsters (smaller average diameter, less polymorphism, and more heterochromatin) as well as apparent reductions in the amounts of hypertrophic SER and lipid moieties seemed to indicate that melatonin caused inhibition of pineal gland activity, and in this respect counteracted the effects of short photoperiod However, an apparent increase in the number of large mitochondria, membrane whorls and dense-cored secretory vesicles in pinealocytes of melatonin-treated hamsters suggests enhanced pineal gland activity
TL;DR: In the transplanted tissue obtained 60 and 100 days after the operation the growth cones were scarce, whereas typical nerve endings became numerous, and these endings contained small clear vesicles which reacted positively when the tissue was treated with A-ZIO-4.4.
Abstract: Pineal glands were grafted under the kidney capsule of mature male rats for periods of 20, 40, 60 and 100 days. Each grafted gland was then excised and divided into two halves. One half was processed for conventional electron microscopy and the other was fixed in aldehydes and then incubated in a zinc iodide-osmium tetroxide mixture at pH 4.4 (A-ZIO-4.4). During the forty days following the operation pinealocytes showed the typical ultrastructural features associated with cells with a high protein and/or peptide secretory activity. On the other hand, during this period, the number of granular vesicles decreased progressively. From day 40 on, the grafted pinealocytes lacked granular vesicles. During the second half of the experimental period the ultrastructure of the pinealocytes indicated that their secretory activity was considerably decreased. During the acute phase of the experimental period numerous structures regarded as the tip of growing axons as well as typical nerve fibres appeared around blood vessels and within the parenchyma of the grafted gland. In the transplanted tissue obtained 60 and 100 days after the operation the growth cones were scarce, whereas typical nerve endings became numerous. These endings contained small clear vesicles which reacted positively when the tissue was treated with A-ZIO-4.4. The secretory activity of the grafted pineal gland and the nature of the nerve fibres which innervate the graft are discussed.
TL;DR: The present study resolves the discrepancy in the literature by establishing that the tubular organelle does indeed occur in untreated male rats, but rather rarely.
Abstract: An electron microscopic survey of pinealocytes from normal rats revealed a highly organized arrangement of cytoplasmic tubules. Such tubules had been previously observed in normal rats (Lin, 1967) and in rats after melatonin administration or two weeks exposure to darkness (Freire and Cardinali, 1975). In a later publication the presence of the tubules was attributed to experimental manipulation resulting in infertility (Gusek, 1976). The present study resolves the discrepancy in the literature by establishing that the tubular organelle does indeed occur in untreated male rats, but rather rarely.
TL;DR: It was concluded that the gerbil pineal cells may be more reactive to various hormonal influence than those of the rat.
Abstract: In the pineal bodies of Wistar rats and mongolian gerbils (Meriones unguiculati) the main concentration of adenyl cyclase was found in capillary endothelial cells, their basal laminae, pericapillary amorphous material and in nerve endings. In the intercellular clefts between the rat pineal cells there was no adenyl cyclase activity, but a considerable amount of this enzyme was detected in the gerbils. The adenyl cyclase lacks completely in the pinealocyte cytoplasms of both species. It was concluded that the gerbil pineal cells may be more reactive to various hormonal influence than those of the rat.
TL;DR: In the pineal organ of the lovebird Uroloncha domestica, bulbous, cup-shaped and elongated outer segments of photoreceptor-like pinealocytes are demonstrated by scanning electron microscopy as discussed by the authors.
Abstract: In the pineal organ of the lovebird, Uroloncha domestica, bulbous, cup-shaped and elongated outer segments of photoreceptor-like pinealocytes are demonstrated by scanning electron microscopy These scarce outer segments, 4–11 μm in length, extend into the pineal lumen The present structural observations speak in favor of photosensitive pinealocytes in the pineal organ of Uroloncha domestica The relation of the photoreceptor-like pinealocytes to acetylcholinesterase-positive nerve cells and a nervous connection between the pineal and the brain indicate that the pineal organ of this passeriform species may be the site of neuroendocrine and photoreceptive functions
TL;DR: The pineal glands obtained from two human fetuses were studied morphologically and the most striking finding was cilia formation by the pinealocyte, which would also endorse the sensory nerve origin of the Pineal glands in man.
Abstract: The pineal glands obtained from two human fetuses were studied morphologically. Light microscopic examinations revealed its structure as an organ consisting of tall or cuboidal cells with a lumen at the center. The most striking finding was obtained through electron microscopic observation, which was cilia formation by the pinealocyte. The cilium was seen quite often, definitely of 9+0 pattern, associated by satellite bodies and rootlet structure. These features are considerably different from those in the human adult but quite similar to those of some species of lower animals, which would also endorse the sensory nerve origin of the pineal glands in man. ACTA PATH. JAP. 27: 527–531, 1977.
Journal Article•
TL;DR: Microscopic study of 54 pineal glands shows that the pineal concretions may have a variable origin: the vessel walls, the interlobular connective tissue, and certain pinealocytes that can then be colored by alcian blue.
Abstract: The study of 747 human pineal glands shows that the weight of this organ is extremely variable. This weight shows seasonal variations. The weight of the pineal is identical in cancerous and non cancerous patients. It is lower (the difference being statistically highly significative) in a great majority of hepatic diseases. Microscopic study of 54 of these pineal glands (those obtained 2 to 6 hours after death) shows that the pineal concretions may have a variable origin: the vessel walls, the interlobular connective tissue, and certain pinealocytes that can then be colored by alcian blue.