PubMed Health⌕ Search

Biomedical subjects

S Deura

Publications and source records attributed to S Deura.

At least 19 recordsLinked to original sources
PubMed1995

Bilateral projections from the superior colliculus to the suprageniculate nucleus in the cat: a WGA-HRP/double fluorescent tracing study.

Following WGA-HRP injection into the right suprageniculate nucleus of the cat brain, retrogradely-labeled neurons were found not only in the ipsilateral, but also in the contralateral superior colliculi. After WGA-HRP injection into the unilateral superior colliculus, anterogradely-labeled axon terminals were observed in the bilateral suprageniculate nuclei, and electron microscopic examination revealed that these were large terminals which made asymmetric synaptic contacts with dendrites. When a different kind of fluorescent tracer was injected into each suprageniculate nucleus (Fast blue and Nuclear yellow), double-labeled neurons were observed in the rostral and middle portions of both superior colliculi. These results suggest that there are direct bilateral projections from the superior colliculus to the suprageniculate nuclei, and that some of these projections originate from branching colliculo-suprageniculate axons.

Animals↗
PubMed1994

Protein products of the bacterial reporter gene are found within axon terminals in the brain of transgenic mice.

The aim of this study is to examine whether protein products of the bacterial reporter gene are localized within axon terminals in transgenic mice. We have previously created transgenic mice carrying a chimeric gene composed of the human tyrosine hydroxylase gene promoter and the bacterial gene encoding chloramphenicol acetyltransferase (CAT). In the present study, we used an antiserum that detects specifically CAT, and examined immunocytochemically the brain of the transgenic mice. At a light microscopic level, CAT immunoreactivity was found in a dense plexus of fibers in the central nucleus of the amygdala, and in cell bodies of the ventral tegmental area. At an electron microscopic level, in the central nucleus of the amygdala, CAT immunoreactivity was observed in axon terminals. In the ventral tegmental area, the immunoreactivity was found in the perikaryal cytoplasm and on the microtubule of dendrites. The present findings suggest that protein products of the bacterial gene may be transported in axons up to their terminals, and also moved along the microtubules of dendrites.

Amygdala↗
PubMed1994

Heterogeneity in calbindin-D28k expression in oxytocin-containing magnocellular neurons of the rat hypothalamus.

We have used a double-labeling immunofluorescence method to examine whether oxytocin-containing magnocellular neurons possess a calcium-binding protein, calbindin-D28k, in the hypothalamus of the rat. In the supraoptic nucleus, most oxytocin-immunoreactive cells were also stained for calbindin-D28k. However, in the magnocellular part of the paraventricular nucleus nearly all oxytocin-labeled cells were devoid of calbindin-D28k. In the anterior commissural nucleus, approximately one-third of oxytocin-stained cells were also calbindin-D28k-immunoreactive, but the other cells were negative for calbindin-D28k. This study indicates that there may be distinct chemical features between oxytocin-containing magnocellular neurons of the supraoptic nucleus compared to those of the paraventricular nucleus.

Animals↗
PubMed1994

Distribution of calretinin, calbindin-D28k, and parvalbumin in the rat thalamus.

The localization of three calcium-binding proteins, calretinin, calbindin-D28k, and parvalbumin, in the rat thalamus was immunohistochemically examined. a) Some thalamic regions revealed cells almost exclusively containing one of the calcium-binding proteins. For example, almost only calretinin-stained cells were found in the central medial and paraventricular nuclei. Calbindin-D28k-stained cells were mostly found in the centrolateral, interanteromedial, anteromedial, and posterior nuclei. Only parvalbumin-positive cells were found in the central part of the reticular nucleus. b) Other regions expressed overlap between the distributions of two cell components composed of different calcium-binding proteins. For example, both calretinin-stained cells and calbindin-D28k-labeled cells were found in the lateroposterior, intermediodorsal, rhomboid, and reuniens nuclei. c) Other regions showed no cells stained for any of the calcium-binding proteins. For example, generally no calcium-binding protein was detected in neurons of the anterodorsal, anteroventral, ventrolateral, ventral posterolateral, ventral posteromedial, or gelatinosus nuclei, or of the central part of the mediodorsal nucleus. These three proteins serve as useful marker for localizing subpopulations of neurons within the thalamus.

Animals↗
PubMed1993

Colocalization of calbindin-D28k with vasopressin in hypothalamic cells of the rat: a double-labeling immunofluorescence study.

By use of a double-labeling immunofluorescence method, we examined whether vasopressin-containing cells possess a calcium-binding protein, calbindin-D28k, in the hypothalamus of the rat. Subpopulations of vasopressin-containing cells varied in their ability to possess calbindin-D28k immunoreactivity in different regions. In the supraoptic nucleus, most vasopressin-immunoreactive cells were also stained for calbindin-D28k. By contrast, in the magnocellular part of the hypothalamic paraventricular nucleus, all vasopressin-labeled cells lacked calbindin-D28k. In the suprachiasmatic nucleus, no calbindin-D28k was found in vasopressin-stained cells. This study shows a further characterization of vasopressin-containing cells of the rat hypothalamus.

Animals↗
PubMed1993

Evidence for localization of the transgene product within axon terminals in the dentate gyrus of transgenic mice expressing human phenylethanolamine N-methyltransferase. A light and electron microscopic immunocytochemical study.

The aim of this study was to examine whether protein products of a transgene are localized within axon terminals in transgenic mice. We have previously created transgenic mice containing a chimeric gene composed of the human dopamine beta-hydroxylase gene promoter and the human phenylethanolamine N-methyltransferase (PNMT) cDNA. In the present study, we used an antiserum that detects specifically human PNMT but not mouse PNMT, and examined immunocytochemically the hippocampal formation of the transgenic mice. At a light microscopic level, immunoreactivity of human PNMT was found in fiber plexuses in the outer molecular layer of the dentate gyrus, and in cell bodies of layer 2 of the entorhinal cortex. At an electron microscopic level, in the outer molecular layer of the dentate gyrus, human PNMT immunoreactivity was observed in axon terminals that formed synapses with dendritic spines. The present study provides the evidence for localization of the transgene's protein products in axon terminals, suggesting axonal transport of the products.

Animals↗
PubMed1993

Immunohistochemical localization of calretinin-, calbindin-D28k- and parvalbumin-containing cells in the hypothalamic paraventricular and supraoptic nuclei of the rat.

The localization of three calcium-binding proteins, calretinin, calbindin-D28k and parvalbumin, in the hypothalamic paraventricular and supraoptic nuclei of the rat was immunohistochemically examined on adjacent sections and their distribution patterns were compared. Overlap between the distribution of calretinin-immunoreactive cells and that of calbindin-D28k-immunostained cells was found in the rostrodorsal part of the supraoptic nucleus, and the caudoventral part of this nucleus contained predominantly calbindin-D28k-stained cells. Cells of the medial and lateral magnocellular subdivisions of the paraventricular nucleus were almost devoid of the calcium-binding proteins examined. No parvalbumin-immunostained cells were observed in either nucleus. This study provides a further characterization of cell bodies in the hypothalamic paraventricular and supraoptic nuclei.

Animals↗
PubMed1993

Direct projections from the cerebellar fastigial nucleus to the thalamic suprageniculate nucleus in the cat studied with the anterograde and retrograde axonal transport of wheat germ agglutinin-horseradish peroxidase.

Axonal transport of WGA-HRP injected into (1) the suprageniculate nucleus or (2) the fastigial nucleus, was investigated. Retrogradely labeled neurons were found in the caudal part of the bilateral fastigial nucleus following injection 1, and anterograde labeled axon terminals were observed in the bilateral suprageniculate nucleus following injection 2. Electron microscopic observations of these terminals revealed that they were large terminals making asymmetric synaptic contacts with dendrites. These results suggest that some neurons in the fastigial nucleus send their axons to the suprageniculate nucleus.

Animals↗
PubMed1993

Ultrastructural localization of calretinin immunoreactivity in lobule V of the rat cerebellum.

Ultrastructural localization of a calcium-binding protein, calretinin, in the cerebellar cortex of the rat was examined with an immunoperoxidase method. The cerebellar lobule V was investigated in detail. In the molecular layer, calretinin immunoreactivity was found in parallel fibers and in their varicosities that formed synapses with unlabeled Purkinje cell dendritic thorns and Golgi cell dendrites. In the granular layer, most granule cells were immunostained for calretinin. Within immunostained granule cells, the labels were found in the cytoplasmic matrix of both the perikaryon and primary dendrite, and in euchromatin patches of the nucleus. Some mossy fiber terminals also stained for calretinin. In the white matter, a few axons were labeled for calretinin and surrounded by unstained myelin sheath. It is suggested that calretinin may play a role at the presynaptic sites of the parallel and mossy fiber terminals.

Animals↗
PubMed1993

Appearance of calretinin-immunoreactive neurons in the upper layers of the rat superior colliculus after eye enucleation.

The effects of retinal deafferentation on a calcium-binding protein, calretinin, in the upper layers (superficial gray layer and optic nerve layer) of the rat superior colliculus were examined. In intact rats and on the ipsilateral side of unilaterally eye-enucleated rats, the superficial gray layer and optic nerve layer contained a few dispersed calretinin-immunoreactive cells. On the contralateral side to the enucleation, the number of immunostained cells in the superficial gray layer and optic nerve layer was increased. These findings suggest that retinal deafferentation results in an increase in contents of calretinin in some cell bodies within the upper layers of the superior colliculus.

Afferent Pathways↗
PubMed1990

Modification of noradrenergic innervation in the cerebellum of mutant rats with Purkinje cell degeneration (jaundiced Gunn rats).

In heterozygous (Jj) and homozygous Gunn rats (jj), cerebellar noradrenergic innervation was examined using immunohistochemical, neurochemical and electrophysiological techniques. Immunohistochemical analysis using an antiserum against tyrosine hydroxylase (TH) revealed a marked enhancement in immunoreactivity largely in the granular layer and the whole nuclei in the jj cerebellum, resulting from an increase in TH-immunoreactive varicose fibers forming synapse-like structures on the somata and dendrites of granule cells or nuclear neurons. The concentration of norepinephrine in both the cortical and nuclear regions of the jj cerebellum was significantly higher than that in the control, whereas no significant difference of this total amount was observed between the jj and Jj cerebella. Injection of norepinephrine into the Jj cerebellar nuclei reduced the firing rate of spontaneous unitary discharges of neurons in the interpositus nucleus. These findings suggest that the the jj cerebellum causes an enhancement of the noradrenergic innervation which may possibly be one of its characteristic alterations.

Animals↗
PubMed1989

[Difference in the postnatal development of the layer structures in the phylogenetically different cat cerebellar cortices].

Although it has long been accepted that the structure of the cerebellar cortex is the same all over its areas, some of the recent studies indicated that there are regional differences in the time course of development of the cortical layer structures as well as in its cytoarchitecture. The cerebellum consists of 3 phylogenetically different areas; archi-, paleo- and neocerebellum, which deals with vestibular, spinal cord and cerebral cortical activities respectively. The development of the structures of cerebellar cortex occurs mostly after birth in the altrical animals, and the control of the posture and movement takes place faster in the trunk than in the extremities in such animals. It could be expected that the postnatal development occurs faster in the phylogenetically older parts than in the newer ones. To elucidate the above mentioned assumption, post-natal development of the cerebellar cortical structures was studied, cytoarchitectonically and cell morphologically, using cats from birth to the adult state. The external granular layer increased in thickness from birth to 2-9th postnatal days, then decreased gradually, and almost disappeared by the 63rd postnatal day. While the molecular and the internal granular layers increased in thickness gradually after birth, and reached the adult level by the 63rd postnatal day. Cytoarchitectonically, postnatal development took place faster in the archicerebellum, next in the paleocerebellum and slowest in the neocerebellum. Silver impregnation study showed the first dendritic arborization of the Purkinje cell appeared on the 7th postnatal day in the arch- and paleocerebellum, while the same phenomenon was observed on the 14th postnatal day in the neocerebellum. The above observations confirmed our assumption that phylogenetically older parts of the cerebellar cortex have faster postnatal development than the newer ones. This is in agreement with the fact that the function of the neuronal activity in these phylogenetically older parts occurs earlier than in the newer parts.

Animals↗
PubMed1988

Cyclic AMP-dependent protein phosphorylation is involved in activation of the potassium current associated with endogenous cellular calcium in Euhadra neurons.

Intracellular injection of the catalytic subunit of cAMP-dependent protein kinase stimulated the outward potassium current associated with endogenous cellular Ca2+ which were abolished by either caffeine or cAMP-dependent protein kinase inhibitor. The principal action of this kinase in current activation may be to release calcium from the intracellular reservoir.

Animals↗