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Abstract
SUMMARYOur light, and electron microscopic (EM) findings within the hypothalamic supraoptic (SO) and paraventricular (PV) nuclei of the normal female rabbit are in agreement with those reported earlier by other investigators for the same nuclei of the dog and rat. The neurons of these nuclei are the hypothalamic synthesis sites of the neurohypophyseal hormones.With the exception of the arcuate nucleus, none of the hypothalamic nuclei associated with the control of adenohypohpyseal function have been studied extensively with the electron microscope. On the basis of our EM findings within the female rabbit hypothalamus, all neurons observed within the preoptic (PO) and suprachiasmatic (SCH) nuclei of the non-mated control animal were morphologically identical to the conventional neuron as described by Peters, Palay and Webster (1970). However, following coitus, castration and laparotomy, many neurons of these nuclei showed subcellular changes that have been repeatedly associated with enhanced protein synthesis. These large ‘neurosecretory’ neurons were usually located near capillaries and characterized by their well developed Rough endoplasmic reticulum (RER) and Golgi profiles, dense populations of mitochondria and lysosomes and by the presence of a homogeneous population of densecore vesicles (DCV) showing a peak distribution of 120-140 nm. Since similar neurons were not observed within the PO and SCH of the normal control rabbit it is suggested that we were observing functional states of the same type of neuron and that these ultrastructural changes occur in response to endocrine manipulation.Two types of neurons described as ‘pale’ and ‘dark’ were observed within the arcuate nucleus of both the control and experimental female rabbit. Ultrastructurally, these neuron types were identical to those described by other investigators for the rat. It has been suggested that the ‘pale’ and ‘dark’ neurons of this hypothalamic nucleus represent functional states of the same type of cell. However, increases in the ratio of ‘dark’ to ‘pale’ neurons as observed within the arcuate nucleus of the rat following castration, were not seen in the rabbit. Similar findings were also not evident within the arcuate nucleus of the female rabbit following coitus.As far as could be determined, all neurons of the ventromedial (VMN) nuclei of both the control and experimental rabbit were morphologically identical to the smaller, conventional type neuron. Certainly, ultrastructural changes similar to those observed within the PO and SCH nuclei of the female rabbit following coitus, castration or laparotomy, were never observed.The basic zonation and subcellular organization of the female rabbit Median Eminence (ME) is similar to that described for other mammalian species. Our EM findings within the external layer of the rabbit ME, however, are not entirely in agreement with the earlier study of Duffy and Menefeef 1965). These investigators reported only one population of DCV within the axon terminals of the rabbit ME external layer. We feel that we have ultrastructural evidence for the presence of at least two distinct populations of DCV within this layer of the rabbit ME. Furthermore, since these vesicle populations occurred within separate axon profiles and terminals, differences in their content and origin are suggested.Certainly, the relationship between releasing factors (RF) and the various populations of DCV observed within the external layer of the mammalian ME is not well established. The smaller (90 nm - 100 nm) DCV we have observed probably contain the catecholamines, while those of larger (120 nm - 140 nm) diameters may well represent the carriers of the RF associated with gonadotropic activity. The latter view is based primarily on our finding or numerous ‘vesicle ghosts’ within the axon terminals abutting the perivascular space (PVS) of portal capillaries of rabbits sacrificed at 10 minutes post-coitus. The mean diameters of 137±14 nm obtained for these ghosts strongly supports the suggested depletion of only the larger of the two DCV populations. Similar changes were not apparent within the axon terminals containing homogenous populations of only the smaller DCV.Unquestionably, the precise hypothalamic synthesis sites for the RF associated with control of adenohypophyseal function, continues to provoke comment. From the results obtained from countless studies that have employed a variety of neuroendocrinilogical techniques, two main hypothalamic centers of RF synthesis have been suggested: a) the medial basal hypothalamus (MBH) or hypophysiotropic area (HTA) and b) the anterior hypothalamus. The ultrastructural studies carried out to date within this laboratoiy are in favour of the latter for the following reasons:1) — the presence of large DCV and ‘vesicle ghosts’ within the external layer of the rabbit ME with diameters similar to those of the large (120-150 nm) DCV synthesized within the PO and SCH nuclei of the same animal in response to coitus, castration and laparotomy.2) — the absence of evidence for the storage of these large DCV within the somata of PO and SCH nuclei, suggesting their immediate transport toward the ME.3) — the absence of any ultrastructural changes within neuron somata of the rabbit arcuate nuclei which might reflect enhanced neurosecretory activity in response to coitus and/or castration.These ultrastructural findings within the rabbit hypothalamus may, therefore, provide the first evidence of a morphological nature for the actual release of RF from their ME storage sites, as well as their synthesis within certain neurons of the anterior hypothalamus.
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Natale G, Cattano D, Abramo A, Forfori F, Fulceri F, Fornai F, Paparelli A, Giunta F. Morphological Evidence that Xenon Neuroprotects against N-Methyl-DL-Aspartic Acid-Induced Damage in the Rat Arcuate Nucleus: A Time-Dependent Study. Ann N Y Acad Sci 2006; 1074:650-8. [PMID: 17105960 DOI: 10.1196/annals.1369.063] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The hyperactivation of glutamate receptors, especially those of the N-methyl-d-aspartate subtype (NMDA), can induce excess calcium entry into cells, leading to neuronal death. Since the anesthetic gas xenon behaves as an NMDA antagonist, the present article investigated, by distinct morphological approaches and after different times, the possible neuroprotectant effects of this gas in a model of neuronal damage induced by N-methyl-dl-aspartic acid (NMA) on rat arcuate nucleus. Rats were assigned to the following groups: controls; xenon exposure; NMA treatment; or xenon exposure + NMA treatment. Animals were placed in an experimental cage and after 10 min a mixture of xenon (or nitrogen) 70% and oxygen 30% was delivered. After 3 h, 1, 2, 5, or 7 days from gas exposure, rats were euthanized and the whole brain was removed and processed for either transmission electron microscopy or light microscopy. In the arcuate nucleus from NMA-treated animals only 40-60% of cell population survived in all times with several degenerating neurons giving the typical appearance of a "bull's eye." At ultrastructural level, chromatin margination, nuclear shrinkage, mitochondria with matrix dilution, dilated endoplasmic cisternae, and electrondense cytoplasm were detected. Xenon alone did not induce changes, but reduced of about 50% NMA-induced cell loss as well as degenerating neurons, with the maximal neuroprotection at 7 days. These results confirm that in the rat arcuate nucleus NMA can induce a severe neuronal damage that is already marked after 3 h. Xenon significantly reduced the neuronal damage at all times and can be then regarded as a promising neuroprotectant agent.
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Affiliation(s)
- Gianfranco Natale
- Department of Human Morphology and Applied Biology, University of Pisa, Via Roma 55, I-56126 Pisa, Italy.
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Otani M. Fine structural changes in the rat arcuate nucleus by forced running stress. THE JAPANESE JOURNAL OF PSYCHIATRY AND NEUROLOGY 1990; 44:99-110. [PMID: 2362397 DOI: 10.1111/j.1440-1819.1990.tb00447.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The forced running stress in male rats induced some fine structural changes in the arcuate nucleus. By inducing stress for 2 days, the number of multilamellar astrocytic wrappings and endoplasmic reticular (ER) whorls increased significantly. After a stress of 12 days, half of the rats remained inactive for several weeks, and the other half regained their normal activity. In the inactive group, the ER whorls were partially degenerated at 2 weeks after the stress. These degenerative changes remained for 14 weeks after the stress with the increased lysosomes and the disorganization of r-ER. These findings may suggest that long-term stress induces degenerative changes in the arcuate nucleus neurons and that some of these changes persist with some aging-like morphological changes.
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Affiliation(s)
- M Otani
- Department of Psychiatry, Mie University School of Medicine, Tsu, Japan
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Zhu CG, Deng DZ, Lu JH, Liu QY, Shi HB. The ultrastructural characteristics and their functional significance of the arcuate nucleus and median eminence. ACTA ACADEMIAE MEDICINAE WUHAN = WU-HAN I HSUEH YUAN HSUEH PAO 1984; 4:1-7. [PMID: 6700921 DOI: 10.1007/bf02856939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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Ohtsuka M, Hisano S, Daikoku S. Electronmicroscopic study of somatostatin-containing neurons in rat arcuate nucleus with special reference to neuronal regulation. Brain Res 1983; 263:191-9. [PMID: 6132670 DOI: 10.1016/0006-8993(83)90312-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
After an intraventricular administration of colchicine, the arcuate nucleus of rat hypothalamus was examined light and electron microscopically by pre-embedding immunohistochemistry for somatostatin. The arcuate nucleus exhibited numerous immunoreactive cell bodies and dense networks of immunoreactive fibers. The fibers appeared to surround immunonegative cell bodies. The immunoreactive cell bodies were multipolar in shape and projected immunoreactive processes to some extent. The immunoreactive cell bodies and fibers received synaptic contacts by immunonegative fiber terminals containing a large number of synaptic clear vesicles. Similarly, immunoreactive somatostatin fibers appeared to terminate upon other immunonegative cell bodies and fibers. The immunoreactive presynaptic terminals contain several labeled granules and numerous synaptic vesicles. In close proximity to these immunolabeled terminals, non-labeled presynaptic terminals were also observed upon the immunonegative cell bodies and fibers. This suggests that in the arcuate nucleus neurons regulated by somatostatin neurons are also under the control of other types of neurons.
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Matsumoto A, Okada R, Arai Y. Synaptic changes in the hypothalamic arcuate nucleus of old male rats. Exp Neurol 1982; 78:583-90. [PMID: 7173371 DOI: 10.1016/0014-4886(82)90076-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Arai Y, Matsumoto A. Synapse formation of the hypothalamic arcuate nucleus during post-natal development in the female rat and its modification by neonatal estrogen treatment. Psychoneuroendocrinology 1978; 3:31-45. [PMID: 644014 DOI: 10.1016/0306-4530(78)90039-2] [Citation(s) in RCA: 105] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Takeichi M, Noda Y. Light and electron microscope studies on the ventromedial hypothalamic nucleus of the cat, with special reference to the fine structures of neurons and synapses. FOLIA PSYCHIATRICA ET NEUROLOGICA JAPONICA 1974; 28:45-64. [PMID: 4406851 DOI: 10.1111/j.1440-1819.1974.tb02285.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Cuello AC, Weiner RI, Ganong WF. Effect of lateral deafferentation on the morphology and catecholamine content of the mediobasal hypothalamus. Brain Res 1973; 59:191-200. [PMID: 4747751 DOI: 10.1016/0006-8993(73)90260-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Ajika K, Hökfelt T. Ultrastructural identification of catecholamine neurones in the hypothalamic periventricular-arcuate nucleus-median eminence complex with special reference to quantitative aspects. Brain Res 1973; 57:97-117. [PMID: 4123790 DOI: 10.1016/0006-8993(73)90571-4] [Citation(s) in RCA: 139] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Zambrano D, Iturriza FC. Hypothalamic-hypophysial relationships in the South American lungfish Lepidosiren paradoxa. Gen Comp Endocrinol 1973; 20:256-73. [PMID: 4699359 DOI: 10.1016/0016-6480(73)90177-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Peute J. Ultrastructural aspects of the nucleus infundibularis dorsalis in the caudal hypothalamus of Xenopus laevis. ZEITSCHRIFT FUR ZELLFORSCHUNG UND MIKROSKOPISCHE ANATOMIE (VIENNA, AUSTRIA : 1948) 1973; 137:513-20. [PMID: 4348310 DOI: 10.1007/bf00307227] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Adamo NJ. Ultrastructural features of the lateral preoptic area, median eminence and arcuate nucleus of the rat. ZEITSCHRIFT FUR ZELLFORSCHUNG UND MIKROSKOPISCHE ANATOMIE (VIENNA, AUSTRIA : 1948) 1972; 127:483-91. [PMID: 4339921 DOI: 10.1007/bf00306867] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Abraham R, Dougherty W, Golberg L, Coulston F. The response of the hypothalamus to high doses of monosodium glutamate in mice and monkeys. Cytochemistry and ultrastructural study of lysosomal changes. Exp Mol Pathol 1971; 15:43-60. [PMID: 4998013 DOI: 10.1016/0014-4800(71)90018-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Daikoku S, Kotsu T, Hashimoto M. Electron microscopic observations on the development of the median eminence in perinatal rats. ZEITSCHRIFT FUR ANATOMIE UND ENTWICKLUNGSGESCHICHTE 1971; 134:311-27. [PMID: 4330890 DOI: 10.1007/bf00519918] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Urano A. Monamine oxidase in the hypothalamo-hypophysial region of the teleosts, Anguilla japonica and Oryzias latipes. ZEITSCHRIFT FUR ZELLFORSCHUNG UND MIKROSKOPISCHE ANATOMIE (VIENNA, AUSTRIA : 1948) 1971; 114:83-94. [PMID: 5541845 DOI: 10.1007/bf00339467] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Sousa-Pinto A. Electron microscopic observations on the possible retinohypothalamic projection in the rat. Exp Brain Res 1970; 11:528-38. [PMID: 5490691 DOI: 10.1007/bf00233973] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Zambrano D. The nucleus lateralis tuberis system of the gobiid fish Gillichthys mirabilis. I. Ultrastructural and histochemical characterization of the nucleus. ZEITSCHRIFT FUR ZELLFORSCHUNG UND MIKROSKOPISCHE ANATOMIE (VIENNA, AUSTRIA : 1948) 1970; 110:9-26. [PMID: 5471204 DOI: 10.1007/bf00343982] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Vigh-Teichmann I, Vigh B, Korits�nszky S, Aros B. Liquorkontaktneurone im Nucleus infundibularis. Cell Tissue Res 1970. [DOI: 10.1007/bf00335940] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Ultrastructural changes in the median eminence of the rat following deafferentation of the basal hypothalamus. ZEITSCHRIFT FUR ZELLFORSCHUNG UND MIKROSKOPISCHE ANATOMIE (VIENNA, AUSTRIA : 1948) 1970; 105:1-32. [PMID: 4910949 DOI: 10.1007/bf00340562] [Citation(s) in RCA: 84] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Adinolfi AM. The fine structure of neurons and synapses in the entopeduncular nucleus of the cat. J Comp Neurol 1969; 135:225-48. [PMID: 5780529 DOI: 10.1002/cne.901350207] [Citation(s) in RCA: 42] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Oehmke HJ, Priedkalns J, Vaupel-von Harnack M, Oksche A. Fluoreszenz- und elektronenmikroskopische Untersuchungen am Zwischenhirn-Hypophysensystem von Passer domesticus. Cell Tissue Res 1969. [DOI: 10.1007/bf00319272] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Vaccarezza OL, Saavedra JP. Granulated vesicles in mitral cells and synaptic terminals of the monkey olfactory bulb. ZEITSCHRIFT FUR ZELLFORSCHUNG UND MIKROSKOPISCHE ANATOMIE (VIENNA, AUSTRIA : 1948) 1968; 87:118-29. [PMID: 4974252 DOI: 10.1007/bf00326564] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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25
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Zambrano D. The arcuate complex of the female rat during the sexual cycle. An electron microscopic study. ZEITSCHRIFT FUR ZELLFORSCHUNG UND MIKROSKOPISCHE ANATOMIE (VIENNA, AUSTRIA : 1948) 1968; 93:560-70. [PMID: 5815137 DOI: 10.1007/bf00338538] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Zambrano D, De Robertis E. The effect of castration upon the ultrastructure of the rat hypothalamus. II. Arcuate nucleus and outer zone of the median eminence. ZEITSCHRIFT FUR ZELLFORSCHUNG UND MIKROSKOPISCHE ANATOMIE (VIENNA, AUSTRIA : 1948) 1968; 87:409-21. [PMID: 5707309 DOI: 10.1007/bf00333690] [Citation(s) in RCA: 51] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Zambrano D, De Robertis E. Ultrastructure of the peptidergic and monoaminergic neurons in the hypothalamic neurosecretory system of anuran batracians. ZEITSCHRIFT FUR ZELLFORSCHUNG UND MIKROSKOPISCHE ANATOMIE (VIENNA, AUSTRIA : 1948) 1968; 90:230-44. [PMID: 5749466 DOI: 10.1007/bf00339431] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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