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Y Ibata

Publications and source records attributed to Y Ibata.

At least 181 records · Page 10Linked to original sources
PubMed1981

Morphological studies on neuroglia. III. Macrophage response and "microgliocytosis" in kainic acid-induced lesions.

Light- and electron-microscopic investigations of kainic acid-induced lesions revealed a marked macrophage response and "microgliocytosis". The hematogenous origin of reactive elements, such as brain macrophages and "'microglia-like reactive cells", was demonstrated when blood phagocytes were labeled with carbon particles or horseradish peroxidase prior to induction of the kainic acid-lesion. The induced lesion showed a proliferation of microglial cells, which led to a state of "microgliocytosis" in the later stage of lesioning. Since it is now generally accepted that microglial cells in the state of "microgliocytosis" are derived from the "microglia-like reactive cells", proliferated microglial cells in the brain lesions are probably of hematogenous origin. The relationships among the brain macrophages, the "microglia-like reactive cells" and the intrinsic microglial cells are discussed.

Animals↗
PubMed1981

Correlative ontogenetic development of catecholamine- and LHRH-containing nerve endings in the median eminence of the rat.

The ontogenetic development of catecholamine (CA)- and LHRH-containing nerve endings in the median eminence of the rat was investigated by combining fluorescence histochemistry and immunohistochemistry in the same tissue section. LHRH-terminals appeared earlier than CA-terminals and were already detectable in the lateral part of the external layer of the central ME on the first day after birth. CA-nerve endings were first seen in a corresponding region of the ME on the seventh postnatal day. At this stage both types of terminals showed the earliest manifestation of a correlative pattern of their distribution. Subsequently the development of both types of nerve endings proceeded rapidly, and at 14 days their distribution pattern corresponded to that in adult animals. The authors conclude that at this stage the CA-neurons play a constant and significant role in the release of LHRH into the portal capillaries. The correlation between both types of nerve endings and the ontogenetic development of the capillary plexuses of the hypophysial portal system is discussed.

Age Factors↗
PubMed1981

Morphological studies on neuroglia. II. Response of glial cells to kainic acid-induced lesions.

The cellular response of non-neuronal elements of the pyramidal cell layer of the rat hippocampus, especially the area CA3, was observed electron microscopically following destruction of this formation by means of intraventricular administration of kainic acid (KA). The neuroglial cell types responding to the KA-induced lesion included astrocytes and the "microglia-like reactive cells". In addition, numerous brain macrophages appeared in the damaged area CA3. Oligodendrocytes and pericytes revealed no morphological changes. Swollen astrocytes were seen in the KA-induced lesion during the early stage. Glial filaments gradually developed in the soma and cell processes of these cells. Brain macrophages were seen in the KA-induced lesion during the early stage; they gradually decreased in number with time. Numerous small cells displaying a dark nucleus appeared in the damaged area CA3 during the first two days after the KA-administration, and gradually increased in number. During the later stage this cell type could hardly be distinguished from the intrinsic microglial cells. It is open to discussion whether this cell type originates from the intrinsic microglial cells or from the hematogenic monocytes; therefore it is designated as "microglia-like reactive cell" in the present study.

Animals↗
PubMed1981

The effect of small doses of kainic acid on the area CA3 of the hippocampal formation. An electron microscopic study.

The toxic effect on area CA3 of the hippocampus of the rat of small doses of kainic acid (KA) injected into the lateral ventricles was examined by electron microscopy. The most characteristic feature revealed was degeneration in the pyramidal cell somata and in their dendrites from as early as 3 hr after injection. We found four types of degenerating pyramidal cells probably corresponding to their susceptibility to KA intoxication. We also detected degenerating preterminal axons and terminals in addition to degenerating pyramidal cells and dendrites. Temporary structural alterations of the mossy fiber endings and intimate adhesional contacts the mossy fiber endings were also observed. The response of the glia to the damage area CA3 was an increase in the number of astroglia and macrophages in the early stage followed later by mobilization of microglia and astroglia for the formation of scar tissue.

Animals↗
PubMed1980

Electron-microscopic observation of adrenergic innervation in guinea pig Eustachian tube.

The precise locations of adrenergic nerve terminals in the Eustachian tube of guinea pigs have, for the first time, been demonstrated by electron microscopy, with application of a false transmitter (5-OHDA). Adrenergic nerve terminals were found in abundance near the arteries in each area of the Eustachian tube. In particular, these terminals were observed just beneath the smooth muscle layer of the arteries. The exact locations of adrenergic nerve terminals in the submucous and gland region are also discussed.

Adrenergic Fibers↗
PubMed1980

Dopamine and alpha-endorphin are contained in different neurons of the arcuate nucleus of hypothalamus as revealed by combined fluorescence histochemistry and immunohistochemistry.

An attempt was made to demonstrate dopamine and alpha-endorphin neurons in the same sections of the arcuate nucleus by combining the techniques of fluorescence histochemistry and immunohistochemistry. Dopamine neurons were found mainly in the medial part near the wall of the third ventricle and alpha-endorphin neurons in the lateral part. We failed to detect any neurons showing simultaneous dopamine fluorescence and alpha-endorphin positive immunoreactivity. We conclude therefore that dopamine synthesizing neurons are probably different from alpha-endorphin synthesizing neurons in the arcuate nucleus.

Animals↗
PubMed1980

Comparison of cardiac lesions induced in rats by isoproterenol and by repeated stress of restraint and water immersion with special reference to etiology of cardiomyopathy.

Cardiac lesions induced in rats by isoproterenol, a potent beta-agonist, and by repeated stress of restraint and water immersion, in which sensitization of beta-adrenergic receptors would be expected to be induced, were investigated morphologically and following facts were revealed. 1) Cardiac lesions induced by isoproterenol, characteristic findings of which were myocardial hypertrophy, myocardial degeneration and myocardial necrosis replaced by interstitial fibrosis, were more analogous to cardiomyopathy than myocardial infarction or cardiac hypertrophy. 2) Cardiac lesions induced by repeated stress of restraint and water immersion, characteristic findings of which were myocardial hypertrophy, myocardial degeneration and myocardial necrosis replaced by interstitial fibrosis, were similar to those induced by isoproterenol. These results suggest that the endogenously induced dominant beta-adrenergic stimulating action during stress may play an important role in the pathogenesis of cardiomyopathy, the specific etiology of which is not yet known.

Adrenal Glands↗
PubMed1979

The location of LH-RH neurons in the rat hypothalamus and their pathways to the median eminence. Experimental immunohistochemistry and radioimmunoassay.

The location of the perikarya of LH-RH neurons in the rat hypothalamus and their pathways to the median eminence were studied by immunohistochemistry and radioimmunoassay after placing stereotaxic electrolytic lesions in several parts of the hypothalamus. The principal location of the cell somata was found to be in the ventral part of the medial preoptic area; their pathways were classified into a main baso-lateral pathway and an accessory descending pathway branching off from the former. The main pathway was found to cross in the vicinity of the corresponding neuronal perikarya. The central median eminence and the dorsal and ventral walls of the tubero-infundibular sulcus of the caudal part of the median eminence are innervated mainly by the baso-lateral pathway. On the other hand, the rostral and most caudal protions of the median eminence are innervated principally by the descending pathway and have a subsidiary dual innervation. The projection of LH-RH neurons to the OVLT is believed to originate from perikarya adjacent to this circumventricular organ.

Animals↗
PubMed1979

Detection of catecholamine and luteinizing hormone-releasing hormone (LH-RH) containing nerve endings in the median eminence and the organon vasculosum laminae terminalis by fluorescence histochemistry and immunohistochemistry on the same microscopic sections.

Distribution of catecholamine (CA) and LH-RH nerve endings in the median eminence (ME) and the organon vasculosum laminae terminalis (OVLT) of the rat was investigated by application of fluorescence histochemistry and immunohistochemistry on the same sections of the tissue. In the ME, those two kinds of endings coexisted in the lateral portion of the middle part of ME, and in the wall of tuberoinfundibular sulcus, where they might be considered to have functional correlation. In the OVLT they were also distributed in fairly near distance, but they were not so closely associated as observed in the ME.

Animals↗
PubMed1979

LH-RH neuron system of the newt by immunohistochemical study.

The location of LH-RH producing neurons, the pathways and terminal distributions of their fibers in the newt, Cynops pyrrhogaster were studied immunohistochemically. The LH-RH positive perikarya are located in the nucleus of the diagonal band of Broca and the medial septal nucleus. No LH-RH immunoreactive neuronal perikarya could be detected in the diencephalon. The pathways of fibers originating from the LH-RH reactive neurons were classified into three groups: the first project to the median eminence, the second to the olfactory bulb and the third to the habenular nucleus. The latter two pathways are extrahypothalamic, similar to those in mammals. These observations are briefly discussed and compared with those in other amphibian and mammalian species.

Animals↗
PubMed1978

Distribution of LH-RH nerve endings in the median eminence of proestrus female rats: fluorescence and peroxidase anti-peroxidase (PAP) immunohistochemistry.

The morphological distribution of the nerve terminals containing LH-RH in the hypothalamus especially in the median eminence of the proestrus female rat was demonstrated by immunohistochemistry, using FITC and peroxidase antibody. The terminals containing LH-RH were classified into four groups on the topographic relationship. LH-RH nerve processes terminated mainly in the infurdibular radix within an elliptical zone surrounding the bases of the infundibular recessus. The heaviest concentration of LH-RH terminals immunohistochemically demonstrated lay on each side of the region extending from the dorsal part of tuberoinfundibular sulcus to the lateral part of the external layer of the superior labium of the infundibulum. We were unable to detect any neuronal soma with the immunoreactivity to LH-RH in the hypothalamic gray matter. The distributional patterns of LH-RH, GH-RIH and monoamine in the median eminence as well as their relationships were briefly discussed.

Animals↗
PubMed1977

Direct projection from the medial preoptic area to the median eminence of the cat.

The projection from the medial preoptic area to the median eminence of the cat was clarified by electron microscopy. After placing the electrolytic lesion in the preoptic area several kinds of degenerating neuronal processes and terminals were observed in the external layer of the median eminence. The one was dark shrunk terminals containing dense cored vesicles, the other was the dark ones containing myeline figure-like structure. The relationship between catecholamine-containing nerve endings and RH/IH-containing endings in the external layer of the median eminence was discussed.

Animals↗
PubMed1977

A morphological survey of the median eminence: fluorescence histochemistry, electron microscopy and immunohistochemistry.

This review is a morphological survey of the median eminence of the rat as revealed by fluorescence histochemistry, electron microscopy and immunohistochemistry. Strong catecholamine fluorescence was diffusely distributed in the external layer of the median eminence especially around the primary capillaries of the portal vessels. In the internal layer, there was a scattering of varicosities or strands with catecholamine fluorescence. The origin of these catecholamine nerve fibers and the function of dopamine (DA) nerve fibers in the external layer were discussed. In the external layer of the median eminence, a large number of nerve endings and processes of various sizes ranging from 0.5 to 2.0 micrometer in diameter were found around pericapillary spaces of the hypophyseal portal system. These nerve endings have been classified into three types according to the morphological features of the vesicles contained in them. Small and large dense cored vesicles (40-60 nm, 70-100 nm in diameter) with very high electron density appeared in the first type nerve endings after 5-OHDA treatment; these endings were regarded as monoaminergic, and more specifically, catecholaminergic. Topographical distribution of luteinizing hormone-releasing hormone (LH-RH) nerve fibers in the median eminence was revealed by immunohistochemistry using the peroxidase antiperoxidase (PAP) method. LH-RH nerve processes and terminals appeared as brown beaded strands and dots in the PAP method. LH-RH terminals in the median eminence were seen to be encircling the infundibular radix. However, they were not evenly distributed; the most notable accumulation of LH-RH reactive dots were located in the region extending from the dorsal part of the tuberoinfundibular sulcus to the lateral part of external layer of the superior infundibular labium at the infundibular radix. Considering the distribution of LH-RH, the growth hormone-release inhibiting hormone (GIH) and the monoamine nerve endings in the median eminence, the function of the anterior pituitary appeared to be regulated by a delicate interrelationship of nerve endings.

Animals↗
PubMed1977

Experimental hydrocephalus of the rat, produced by cisternal injection of kaolin-solution (author's transl).

Experimental hydrocephalus was produced in rats in high percentage, by direct injection of kaolin-solution into the cisterna magna under a operating microscope. Rats with hydrocephalus showed retarded development of the body. The skull enlarged round and became so thin, that the cortical vessels were observed through the skull. The brain showed marked internal hydrocephalus, retaining cerebrospinal fluid passage in the ventricular system, but there was an obstruction at the ambient cistern and the basal cistern. Review of the literature dealing with the methods to produce acquired hydrocephalus showed that this is the first report of experimental hydrocephalus of the rat produced by injecting kaolin-solution.

Animals↗
PubMed1976

The zinc iodide-osmium tetroxide (ZIO) reaction on nerve endings in the median eminence of the rat under normal and experimental conditions.

The reaction of nerve endings in the median eminence of the rat to zinc iodide-osmium tetroxide (ZIO) staining was examined electron microscopically under normal and experimental conditions. The experimental condition of catecholamine exhaustion in the nerve endings was induced by the administration of H44/68 and reserpine. Vesicles in the terminals of catecholaminergic nerves reacted similarly to ZIO staining in both normal and experimental material. The majority of synaptic vesicles in various terminals gave a positive ZIO reaction. The neurosecretory elementary granules, however, failed to react with ZIO. On the other hand, some nerve terminals in the external layer of the median eminence showed a strong positive reaction in the cytoplasmic matrix, in mitochondria as well as in synaptic vesicles. These findings strongly suggest that the ZIO-positive substance in nerve terminals is not the transmitter itself, i.e. the monoamine, but rather represents a range of substances commonly found in various kinds of synaptic vesicles and is probably proteinaceous in nature. A brief discussion is also given on the difference in ZIO reactivity between neurosecretory elementary granules and small vesicles in the hypothalamo-hypophyseal tract.

Animals↗