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Page 184 of 547-
Selective demonstration of a type of synaptic vesicle by phosphotungstic acid staining.
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[Some data from electron microscopy on neurosecretory cells of the supraoptic nucleus in white mice].
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Quantitative ultrastructural study of prolactin cells from lactating mice during a 24-hour period.
A quantitative ultrastructural morphometric study was performed on the prolactin (PRL) cells of lactating mice, at different times in a circadian period. The results showed significant time fluctuations in the percentages of cytoplasmic volume occupied by several organelles. The endoplasmic reticulum appeared more developed during the dark period, indicating a higher synthesis of secretory material in this phase. The Golgi complex, including an increased number of immature granules, was found remarkably enlarged during the light period. Moreover, the release of PRL would be increased during the dark phase, as judged by the diminution of the secretory granules and the higher degree of emiocytotic activity. The present morphometric approach in the detection of circadian variations of PRL secretion in lactating mice is emphasized.
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[Ultrastructural study of the median eminence of the cat].
The electron microscopic study of the median eminence in cats sacrified during the growth period (36 hours to 30 days after-birth) and in adult cats leads to the following conclusions: 1) The external infundibular zone of newborn kittens (36 hours postpartum) shows very few capillary loops and it lacks a palissade appearance. On the seventh day a palissade layer and penetrating capillary loops are observed. 2) There are no myelinated fibers in the fibrillar layer of the median eminence external infundibular zone during the growth-period. The number and size of Herring bodies increase after the seventh day. In adult cats, Herring bodies may be 50 microns long and some show myelinic sheaths. 3) In adult cats, the nerve endings which surround the capillary loops penetrating into the median eminence, are in direct contact with the lamina basalis, while the nerve endings of the palissade layer are always separated from the capillary space of the hypophyseal portal plexus by glial cell prolongations.
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Localization of indoleamine and protein synthesis in the mammalian pineal gland.
In a table, conditions and compounds have been listed either known or suggested to influence pineal function. In the same model, systems and organs and their products are indicated the function or, respectively, the quantity of which are known or suggested to be influenced by pineal secretory substances. Of the latter, indoleamines and polypeptides are mentioned only although it is now known that also other low molecular weight biologically active compounds are produced by the gland. Problems relating to the localization of indoleamine and protein synthesis in the pinealocyte are discussed. The synthesis of indoleamines, at least of serotonin, may occur freely in the cytosol although, especially in non-mammals, the presence of serotonin seems to be preferentially, but perhaps secondarily, related to the secretory dense-core vesicles. Questions concerning the exact function of pineal melatonin are shortly dealt with. The granules of the secretory vesicles probably also contain a proteinaceous substance which, notwithstanding its unknown chemical nature, has been considered the antigonadotropic principle by some authors. Recent investigations on the production of active proteinaceous compounds in cisterns of the endoplasmic reticulum and between the layers of the nuclear envelope are reviewed. These substances are not concentrated in secretory granular vesicles, so scarce in the pinealocyte which proteinaceous active principle is produced in still largely unsolved as is their exact chemical composition.
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Structure of the nongranulated cells in the hypophyseal rostral pars distalis of cyclostomes and actinopterygians.
The structure of the nongranulated cells in the sea lamprey adenohypophysis and similar cells of the rostral pars distalis in a number of actinopterygian fishes was examined with the aim of determining the role(s) of these cells in pituitary function. A number of possible roles are proposed for the nongranulated cells. In salmonids and Amia calva the cells may be involved in the active movement of material into or from the follicle lumina. The structure of the nongranulated cells in in vitro cultured and in in vivo transplanted trout rostral pars distalis also suggests a phagocytotic role for these cell. In teleosts with a non-follicular rostral pars distalis the nongranulated cells and in the subsequent dispersal of the hormone (and/or carrier substance) into the peripheral circulation.
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[Spatial reorganization of the organelles of catecholamine-synthesizing group A1 neurons during emotional stress].
Dynamics of spatial reorganization of organellas in catecholamine-synthesizing neurons of A1 group, that participate in reactions of the cardiovascular control, have been studied under normal conditions and under stimulation of the ventromedial nucleus in the hypothalamus. During transition of the hypertensive reaction into the hypotensive one, concentration of various organellas in the Golgi complex area and in the perinuclear zone is intensively increasing. Deep mutual nucleocytoplasmic invaginations appear. The spatial reorganization of the organellas in the neuron demonstrates that some new integrations take place in its metabolic system and reflects its another qualitative state. This serves as an impulse for structural adaptive modifications of the synaptic apparatus. There is a reason to suppose that one of the ways for organization of the alive system stability to an emotional stress is the way of reorganization of the connections, creation of another physiological architecture of the functional system, that can ensure the adaptive reactions of the organism to emotional overstrains.
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The origin of pituitary cysts in the rostral pars distalis of the nine-spined stickleback, Pungitius pungitius L.
Pituitary cysts in the nine-spined stickleback, Pungitius pungitius L., developed next to blood vessels passing through the prolactin zone of the rostral pars distalis to the connective tissue capsule at its periphery. Cysts were most frequent when pituitaries were large compared with body lengths. However, the incidence of cysts could not be closely related to body length alone. As the rostral pars distalis is more highly vascularised in fish with large pituitaries, and as there was no evidence of accumulating secretion around these blood vessels, it is suggested that cysts develop when vascular demands (or supplies) become excessive. Associated with the greater vascularity of the rostral pars distalis in large pituitaries was a remarkable development of non-granulated cells. Indeed cysts may originate as enlarged intercellular spaces between such cells, as the latter often surround blood vessels. The non-granulated cells are also important in enlarging cyst cavities (by phagocytosing prolactin-cell debris) and perhaps for maintaining their structural integrity. It is suggested that the macrophages within cyst cavities are derived from the non-granulated cells.
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Specific paracrystalline structures of rough endoplasmic reticulum in the follicular (stellate) cells of the dog adenohypophysis.
The fine structure of follicular cells of the adenohypophysis was examined in fetal, neonatal, and adult beagle dogs. Prior to birth, undifferentiated follicular cells are common. At birth mature cells that form follicles are routinely encountered. The fine structural appearance of follicular cells is unchanged between birth and adulthood. Follicular cells of puppies and adults are, however, distinguished by the presence of unusual complexes within distended cisternae of the rough endoplasmic reticulum. These complexes vary greatly in morphology, some appear as a maze of interconnecting tubules while others show a highly organized paracrystalline configuration. The presence of these paracrystalloid structures in follicular cells supports the view that they represent a distinct pituitary cell type.
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Comparative ultrastructural observations on the pineal organ of the pipefish, Syngnatus acus, and the seahorse, Hippocampus hudsonius.
A comparative ultrastructural study was made of the pineal organ of two related species of the Syngnathidae, the pipefish, Syngnathus acus, and the seahorse, Hippocampus hudsonius. Both species have a relatively small pineal organ, which ultrastructurally shows several similarities with the pineal of other teleosts. In the pineal organ of Syngnathus acus, the photoreceptor cells have well-developed outer segments consisting of about 15 to 60 saccules. The pineal supporting cells are characterized by the presence of numerous myeloid bodies. In Hippocampus hudsonius the pineal outer segments are scarce and poorly developed; generally, they show not more than 20 saccules. The apical parts of the supporting cells contain dense-core vesicles with a diameter varying from 100 to 180 nm. Corresponding vesicles were not observed in the pineal organ of Syngnathus acus. Arguments are presented for the suggestion that the pineal organ of the Syngnathidae, in spite of its relatively small size, still has a functional significance. In Syngnathus acus, light reaching the pineal organ directly might have a regulating effect on pineal activity. In Hippocampus hudsonius, however, light acting directly on the pineal organ appears to have minor effect on pineal function.