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Biomedical subjects

R Yui

Publications and source records attributed to R Yui.

27 records · Page 2Linked to original sources
PubMed1982

An electron microscopic study on enkephalin-like immunoreactive nerve fibers in the celiac ganglion of guinea pigs.

Enkephalin-like immunoreactive nerve fibers in the celiac ganglion of guinea pigs were characterized by a high population of large granular vesicles mixed with small clear vesicles. The immunoreactive material is confined to the large granular vesicles. The immunoreactive nerve fibers formed many axo-dendritic as well as axo-somatic synapses and also formed a few synapses with presumed preganglionic axons containing numerous vesicles. The immunoreactive fibers were regarded as presynaptic at these synapses. These findings suggest that enkephalin might play a role as a neurotransmitter or neuromodulator in the ganglionic transmission of this prevertebral ganglion.

Animals↗
PubMed1982

On the occurrence and physiological effect of somatostatin in the ciliary ganglion of cats.

Somatostatin-like immunoreactive nerve fibers occurred among and around ganglion cells in the form of punctate structures or varicose processes in the cat ciliary ganglion. The density of the fibers varied greatly from region to region and approximately 25% of the whole population of neuronal soma that appeared in a single section were surrounded by immunoreactive fibers. No somatostatin-positive cell bodies were observed. Application of somatostatin to this ganglion in vitro by superfusion induced membrane hyperpolarization in approximately 60% of the neurons examined. The hyperpolarization was preserved in a low Ca/high Mg medium. This response was associated with a decrease in input membrane resistance and was reversed in polarity at nearly --90 mV. The present findings suggest that somatostatin may play a role as a neurotransmitter or modulator in this parasympathetic ganglion.

Animals↗
PubMed1982

An electron microscopic study on VIP-like immunoreactive nerve fibers in the celiac ganglion of guinea pigs.

An immuno-electron microscopic study revealed that VIP-like immunoreactive nerve fibers in the celiac ganglion of guinea pigs were characterized by a conspicuously numerous large granular vesicles mixed with small clear vesicles. The immunoreactive materials were localized in the core of the large granular vesicles and a distinct halo was recognized between the core and the limiting membrane of the vesicles. These fibers made numerous axo-dendritic and a few axo-somatic synapses with the post-ganglionic principal neurons and also formed some synapses with vesicle-containing neuronal profiles which are presumably preganglionic axons. The immunoreactive fibers were presynaptic at all these synaptic sites. In addition, some synaptic contacts were found between two adjacent immunoreactive nerve fibers. These findings strongly suggests that VIP might be involved in the ganglionic transmission of the prevertebral ganglia.

Animals↗
PubMed1981

An electron microscopic study on substance P-like immunoreactive nerve fibers in the celiac ganglion of guinea pigs.

Substance P-immunoreactive nerve fibers in the celiac ganglion of guinea pigs were revealed with the PAP procedures to contain abundant small clear vesicles mixed with a few large granular vesicles. The immunoreactive materials were localized around cytoplasmic components including vesicles and on the inside of the plasma membrane. The immunoreactive fibers directly apposed to unlabelled dendrites of postganglionic neurons and also to preganglionic axons. Morphological features of synapses could be identified at sites of apposition to unlabelled dendrites: clusters of vesicles in the immunoreactive fibers, intercellular spaces of about 20 nm, and an intermediate density on the postjunctional membrane of unlabelled dendrites. On the other hand, no distinct electron density together with accumulations of vesicles was seen underneath the apposed membrane of unlabelled axons. These findings indicate at the ultrastructural level that substance P-fibers form axo-dendritic synapses on the postganglionic neurons and also suggest the presence of the presynaptic interaction between substance P-fibers and some preganglionic axons in this ganglion.

Animals↗
PubMed1981

Evolutionary aspects of "brain-gut peptides": an immunohistochemical study.

Phylogeny of biogenic peptides and their source cells was studied by immunohistochemistry and electron microscopy. The distribution of the peptide containing neurons and paraneurons in the brain and in the gastroenteropancreatic endocrine system was depicted, especially in the bullfrog as the representative of deuterostomia and in the cockroach and some other insects as the representatives of protostomia. Stress was given to: (1) calcitonin-immunoreactive neurons in bullfrog hypothalamus and PP-reactive neurons in the cockroach protocerebrum as instances of transmissional-hormonal partition of a neuropeptide, (2) open-type endocrine cells in the gut structurally and functionally common to the protostomia and deuterostomia, and (3) phylogeny of the prohormones with special reference to big gastrin and proglucagon (glicentin).

Animals↗
PubMed1981

Immunohistochemical study of the pancreatic endocrine cells of the ray, Dasyatis akajei.

The pancreatic endocrine cells of the ray, Dasyatis akajei was studied by aldehyde-fuchsin-Masson-Goldner's staining and by immunohistochemical methods. The pancreatic endocrine cells of the ray do not form islets by represent the most primitive distribution among elasmobranchs, occupying the outer layer of the double-layered duct epithelium of the pancreas. The endocrine cells showed no evidence of reaching the duct lumen, i. e., they are closed in type. By the use of immunohistochemical techniques, insulin-, glucagon-, somatostatin-and pancreatic polypeptide (PP)-like immunoreactivities were detected in the endocrine cells. The PP-positive cells could not be differentiated from the somatostatin-immunoreactive cells, although the former were smaller in number. The possible reasons for this result were discussed. The present finding supports the view that those four peptides are essential regulatory substances of the endocrine system of the pancreas at a fairy early stage of vertebrate evolution.

Animals↗