Search PubMed⌕ Search

Biomedical subjects

M Araki

Publications and source records attributed to M Araki.

At least 217 records · Page 12Linked to original sources
PubMed1984

Differentiation of monoamine accumulating neuron systems in cultured chick retina: an immunohistochemical and fluorescence histochemical study.

Monoamine-containing neurons (dopamine and serotonin) have been reported to be localized among the cells in the inner nuclear layer (INL) of the chick retina. To examine the development of these neurons and whether they have an ability to synthesize serotonin (5-HT) or dopamine from exogenous precursors, we administered monoamines and their precursors in vitro as well as in situ and examined monoamine neuronal differentiation histochemically. In the chick retina, serotonin-containing neurons were found among amacrine cells. Two other types of serotonin-accumulating neurons were observed in the INL. One also had the ability to take up tryptophan and 5-hydroxytryptophan (5-HTP) and convert them to serotonin. In the monolayer culture from 61/2-day-old chick embryonic retinas, serotonin-containing neurons were observed on the 4th day of culture, increased in number until the 8th day, but had almost disappeared by the 15th day. After incubation of 8 day-cultures with 5-hydroxytryptophan, the number of serotonin-immunoreactive cells was at least twice that seen in untreated cultures. On the 20th day of culture, the same percentage of cells had the capability to take up serotonin, but the number of those which took up 5-hydroxytryptophan and decarboxylated it to serotonin had decreased markedly. Dopaminergic amacrine cells have also been found in the INL and shown to take up exogenously administered L-DOPA. In cultures, no dopamine-containing cells were observed with the present fluorescence histochemistry without prior incubation with DOPA.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Presumptive gamma-aminobutyric acid pathways from the midbrain to the superior colliculus studied by a combined horseradish peroxidase-gamma-aminobutyric acid transaminase pharmacohistochemical method.

A pharmacohistochemical method for gamma-aminobutyric acid transaminase, the key enzyme for gamma-aminobutyric acid metabolism, has been combined with retrograde tracing by horseradish peroxidase, to a study of projections from the midbrain to the superior colliculus. The results indicate projections from the substantia nigra zona reticulata, the zona incerta and the reticular formation of the mesencephalon which are exclusively from neurons staining intensely for gamma-aminobutyric acid transaminase and presumptively gamma-aminobutyric acid as their transmitter. The projection from the ventral lateral geniculate body to the superior colliculus, on the other hand, comes from cells which do not stain for gamma-aminobutyric acid transaminase and therefore do probably not use gamma-aminobutyric acid as their transmitter.

4-Aminobutyrate Transaminase↗
PubMed1984

Immunocytochemical localization of rhodopsin-like immunoreactivity in the outer segments of the rods and single cones of chick retina.

Photoreceptor cells in chick retina consist of a rod and five types of cones. Immunocytochemical techniques have pinpointed rhodopsin-like immunoreactivity in the outer segments of some single cones as well as in rods. The antibody used in our study was raised against bovine rhodopsin purified by SDS-polyacrylamide gel electrophoresis. No rhodopsin-like immunoreactivity was found in the principal and accessory cone. Epon-embedded, semi-thin sections also were treated with potassium hydroxide to remove epoxy resin and then subjected to immunoreaction with the antibody. With this method the same results were obtained repeatedly, and the possibility of staining failure in double cones and some single cones due to insufficient permeability was avoided. Electron microscopy revealed that the oil droplets of stained single cones are slightly smaller and are located in a more vitreal position than those of unstained single cones. The stained single cones are presumed to be types II and III single cones. In the inner segment, especially in the Golgi region and the rER, no staining was seen. Only slight staining was found in the connecting cilium and in the small vesicular or granular structure between the oil droplet and the plasma membrane facing the heavily stained outer segment. This suggests that opsin is incorporated into the plasma membrane in the distal portion of the inner segment.

Animals↗
PubMed1983

Electron microscopic histochemistry of alkaline phosphatase activity in the developing chick retina.

The present paper describes ultrastructural localization of non-specific alkaline phosphatase (ALPase) activity in the chick retina during late embryonic development and after hatching. In the newly-hatched chick retina, intense ALPase activity was found in the outer plexiform layer (OPL), and a less intense reaction was found in the ganglion cell layer and at the outer limiting membrane. Electron microscopic histochemistry revealed that bipolar and horizontal dendrites within the OPL displayed intense reaction product along their plasma membranes. Only horizontal cells showed reaction product on almost their whole circumference. Müller cells also showed reaction product on the plasma membrane in the ganglion cell layer and on the microvilli at their apical portion. The reaction product in the OPL was first recognizable in the retina of the 13- to 14-day-old embryonic chick, and its intensity increased during further development. Little reaction product was found in Müller cells at the embryonic stage. The function of ALPase activity is discussed in relation to the development of the OPL and the nutrient supply for the neural retina.

Alkaline Phosphatase↗
PubMed1983

Dopaminergic cell differentiation in the developing chick retina.

The distribution and morphology of dopaminergic (DA) neurons in the chick retina was studied in the course of development. Fluorescent DA cells were first detected on the 13th day of incubation. They were always found in positions two or three cell rows externally from the junction between the inner plexiform layer (IPL) and inner nuclear layer (INL). On the 14th day, DA cells were found in the innermost row of the INL. Subsequently their processes extended not only bilaterally along the IPL-INL junction but also vertically into the IPL. As a result, three fiber layers were formed as laminae 1, 3 and 5 in the IPL. In the newly-hatched chick retina, a number of growth cone-like fluorescent structures with fine spikes were seen at the IPL-INL junction, indicating that DA fibers were still growing and elongating at least at hatching. On the 4th postnatal day, the ramification of dendritic processes was very prominent and they often showed a spiral configuration.

Animals↗
PubMed1983

Primary monolayer culture of rat ependymal cells: an ultrastructural study.

Dissociated cerebella of newborn rats were cultured in vitro as a monolayer for a long period, and ependymal cell differentiation was investigated by scanning and transmission electron microscopy. Cells with actively beating cilia were recognized on the 3rd day, and gradually increased in number thereafter. At nine months of culturing, a number of areas appeared, some of which consisted of several hundreds of ciliated cells. Cultured ependymal cells showed a striking resemblance in their fine structure to the intact ependyma. They were always found to grow upon the feltwork of astrocytic processes which served as a subependymal structure, as observed in the intact ependyma. It is possible that astrocytes may play some role in ependymal differentiation. Cultured ependymal cells are helpful in understanding the control mechanism for the metachronal cilial movement.

Animals↗