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Biomedical subjects

M Tohyama

Publications and source records attributed to M Tohyama.

At least 397 records · Page 22Linked to original sources
PubMed1987

The histaminergic innervation of the mesencephalic nucleus of the trigeminal nerve in rat brain: a light and electron microscopical study.

Histaminergic fibers in the mesencephalic nucleus of the trigeminal nerve of Long-Evans rats were examined by light and electron microscopy after peroxidase-antiperoxidase immunocytochemical staining for histidine decarboxylase (HDC) as a marker. By light microscopy, neurons in the mesencephalic nucleus of the trigeminal nerve were seen to be surrounded by a number of HDC-like immunoreactive (HDCI) fibers, suggesting the presence of axo-somatic contact. This finding was supported by immunoelectron microscopic demonstration of synaptic contact of some HDCI fibers with the soma of the neurons in this nucleus. These findings indicate that histamine is involved in the sensory regulation of movement of the masticatory muscles at the level of the trigeminal mesencephalic nucleus.

Animals↗
PubMed1987

Projections of bombesin-like immunoreactive fibers from the rat stomach to the celiac ganglion revealed by a double-labeling technique.

Gastrofugal bombesin (BOM)-like immunoreactive (BOMI) structures in the rat were studied by immunocytochemistry combined with retrograde labeling. Transection of the mesenteric nerve peripheral to the celiac ganglion resulted in the complete disappearance of BOMI nerve terminals, whereas transection of the splanchnic nerves did not alter the immunoreactivity. Injection of biotinylated wheat germ agglutinin into the celiac ganglion labeled several neurons in the myenteric ganglion of the stomach. Simultaneous staining with antiserum against BOM showed that some of them are BOMI-positive. These findings demonstrate that BOMI neurons in the myenteric ganglion of the rat stomach project to the celiac ganglion.

Afferent Pathways↗
PubMed1987

Transient appearance of calcitonin gene-related peptide-like immunoreactive fibers in the developing cerebellum of the rat.

A plexus of calcitonin gene-related peptide (CGRP)-containing fibers were transiently found in the developing cerebellum of the rat by means of the indirect immunofluorescent method. CGRP-like immunoreactive fibers appeared in the cerebellum by embryonic day 22. Immunoreactive fibers rapidly increased and these made a dense plexus in the Purkinje cell layer by postnatal day 2. However, only a few if any immunoreactive fibers were seen in the Purkinje cell layer or molecular layer of adult rats.

Animals↗
PubMed1987

Neostriatal cholinergic neurons receive direct synaptic inputs from dopaminergic axons.

We used an electron microscopic 'mirror technique' to determine whether cholinergic neurons are in direct synaptic contact with dopaminergic axons in the rat neostriatum. Tyrosine hydroxylase-immunoreactive axons make synaptic contacts with the somata and proximal dendrites of large choline acetyltransferase-immunoreactive striatal neurons which are thought to be interneurons. This provides morphological evidence that nigrostriatal dopaminergic neurons can influence monosynaptically the striatal cholinergic neurons.

Adrenergic Fibers↗
PubMed1987

Demonstration of histaminergic neurons in horizontal cells of guinea pig retina.

The existence of L-histidine decarboxylase (HDC, EC 4.1.1.22)-like immunoreactive (HDC-I) cells in guinea pig retina was demonstrated using antiserum raised against HDC purified from fetal rat liver. The anti-HDC antiserum partially cross-reacted guinea pig L-DOPA decarboxylase (DDC, EC 4.1.1.28), so the histaminergic neurons were carefully identified. Comparison of HDC-I and DDC-like immunoreactive (DDC-I) cell types in adjacent sections revealed that HDC-I structures were found in some horizontal cells and amacrine cells, and double-staining procedures with anti-HDC antiserum and monoclonal anti-DDC antibody showed that HDC-I horizontal cells had no DDC-I structures, but all the HDC-I amacrine cells had DDC-I structures. From the results, some horizontal cells (with HDC-like immunoreactivities but without DDC-like immunoreactivities) were concluded to be histaminergic.

Animals↗
PubMed1987

Hippocampofugal gamma-aminobutyric acid (GABA)-containing neuron system in the rat: a study using a double-labeling method that combines retrograde tracing and immunocytochemistry.

Using a double-labeling method that combines retrograde tracing and immunocytochemistry, we demonstrated the presence of a hippocampofugal gamma-aminobutyric acid (GABA)-like immunoreactive (GABA-LI) neuron system in the rat. As a preliminary experiment, knife-cut of the dorsal fornix was made and it resulted in a remarkable accumulation of GABA-LI fibers caudal to the section. This suggested the presence of a hippocampofugal GABAergic projection. The hypothesis was confirmed by the double-labeling method: injection of the biotinylated wheat germ agglutinin (B-WGA) into the septum resulted in labeling numerous neurons in the hippocampus and some of them also showed GABA-like immunoreactivity by the simultaneous immunostaining with the antiserum against GABA.

Animals↗
PubMed1987

Afferent and efferent enkephalinergic systems of the tegmental nuclei of Gudden in the rat: an immunocytochemical study.

We studied the afferent source of L-enkephalin-like immunoreactive (L-ENKLI) fibers in the ventral tegmental nucleus (VT) of Gudden, and efferent and afferent connections of L-ENKLI structures in the dorsal part of the dorsal tegmental nucleus (DDT) of Gudden in the rat, using immunocytochemistry combined with knife-cut and lesion experiments. The VT had a dense plexus of L-ENKLI fibers but no L-ENKLI cells. Destruction of the dorsal premammillary nucleus and medial mammillary nucleus pars medialis, which contained a large group of L-ENKLI neurons, markedly reduced L-ENKLI fibers in the ipsilateral VT, suggesting that most of these fibers originate in these nuclei. The DDT contained a large collection of L-ENKLI neurons together with dense L-ENKLI fibers. Destruction of the DDT caused a contralateral marked reduction of L-ENKLI fibers in the dorsolateral part of the interpeduncular nucleus (DL), suggesting that L-ENKLI neurons in the DDT project contralaterally to the DL. L-ENKLI fibers in the DDT may be of intrinsic origin.

Animals↗
PubMed1987

Calcitonin gene-related peptide-like immunoreactive sensory fibers form synaptic contact with sympathetic neurons in the rat celiac ganglion.

The present study demonstrates synaptic contact between calcitonin gene-related peptide (CGRP)-like immunoreactive axon terminals and sympathetic neurons in the rat celiac ganglion. Our observations suggest that sensory ganglion neurons directly regulate the sympathetic activity via synapses, because CGRP immunoreactive (CGRPI) fibers in this ganglion are supplied by the sensory ganglia.

Animals↗
PubMed1987

Calcitonin gene related peptide stimulates adenylate cyclase activity in rat striated muscle.

Rat calcitonin gene related peptide (CGRP) and salmon calcitonin (CT) stimulated adenylate cyclase activity in a dose-dependent manner in the rat diaphragm and in the kidney. The ED50 value of rat CGRP was lower and that of salmon CT was higher in the diaphragm than in the kidney. These results suggest that CGRP stimulates adenylate cyclase activity in the striated muscle by reacting with sites distinct from the site in the kidney.

Adenylyl Cyclases↗
PubMed1987

Distribution of substance P-like immunoreactive structures in the brainstem of the adult human brain: an immunocytochemical study.

The distribution of substance P-like immunoreactive (SPI) structures in the brainstem of the adult human was investigated by the avidin-biotinylated peroxidase complex method for immunocytochemistry. SPI structures were widely distributed in the brainstem, and particularly dense in the substantia nigra, peripheral portions of the colliculus inferior, central gray matter, parabrachial area, nucleus dorsalis tegmenti of Gudden, nucleus reticularis tegmenti pontis, nucleus tractus solitarii, nucleus dorsalis motorius nervi vagi, and nucleus tractus spinalis nervi trigemini.

Aged↗
PubMed1987

Immunocytochemical localizations of cytosolic and mitochondrial glutamic oxaloacetic transaminase isozymes in rat primary sensory neurons as a marker for the glutamate neuronal system.

The localization of cytosolic (s-) and mitochondrial (m-) glutamic oxaloacetic transaminase (GOT) was examined in the rat trigeminal, jugular and dorsal root ganglia by means of an indirect immunofluorescence method using antibodies specific for s- and m-GOT. Staining of s-GOT-like immunoreactivity was seen in giant, large, medium and small cells in these ganglia. On the other hand, m-GOT-like immunoreactivity was not seen in them. The distribution of GOT suggests that glutamate may be a transmitter released from primary sensory neurons.

Animals↗
PubMed1987

Analysis of the habenulopetal enkephalinergic system in the rat brain: an immunohistochemical study.

The enkephalinergic afferent system in the rat habenula was examined by the indirect immunofluorescence method with antibodies against leucine-enkephalin. Leucine-enkephalin-like immunoreactive (L-ENKI) fibers were observed in the dorsal portion of the medial habenular nucleus (MHb), the intermediate portion of the lateral habenular nucleus (LHb), and the border zone between the MHb and the LHb (BZHb). Knife-cut studies demonstrated that almost all the fibers were supplied via the stria medullaris. Also two discrete ENKergic afferents to the MHb and the LHb were found by several kinds of lesion studies: the MHb was ipsilaterally innervated from L-ENKI neurons in "septoperiventricular area," which is the junctional area between the ventral supracommissural septum and the rostral thalamic periventricular region. The LHb was ipsilaterally innervated from L-ENKI neurons in the rostral portion of the lateral hypothalamus. Our findings also suggested that the L-ENKI fibers in the BZHb are supplied via the stria medullaris with an ipsilateral predominance and that, at the most caudal level, they arise not only from the ipsilateral stria medullaris but also from the contralateral stria medullaris via the habenular commissure.

Animals↗
PubMed1987

Nigrostriatal dopamine neurons receive substance P-ergic inputs in the substantia nigra: application of the immunoelectron microscopic mirror technique to fluorescent double-staining for transmitter-specific projections.

A direct synaptic contact between nigrostriatal dopamine neurons and substance P axons in the substantia nigra was demonstrated using the immunoelectron microscopic mirror technique combined with the fluorescent double-staining method for transmitter-specific projections. Substance P-immunoreactive terminals were found to make synaptic contact with nigral cells exhibiting tyrosine hydroxylase immunoreactivity and retrograde fluorescent labeling following injection of biotinylated lectin into the neostriatum. It appears that substance P afferents directly affect nigrostriatal dopamine neurons in the substantia nigra via the synaptic contacts.

Animals↗
PubMed1987

Mammillothalamic enkephalinergic pathway in the rat: an immunocytochemical analysis.

We studied the afferent sources of Leu-enkephalin (ENK) -like immunoreactive (ENKI) fibers in the anteroventral thalamic nucleus (AV) of the rat using experimental immunohistochemistry. These fibers were markedly fewer on the operated side after the destruction of the medial mammillary nucleus pars medialis where a number of ENKI cells were observed. This strongly suggests that these ENKI cells project ipsilaterally to the AV. ENKI fibers seemed to reach the AV via the mammillothalamic tract.

Animals↗
PubMed1987

Origin of leucine-enkephalin fibers and their two main afferent pathways in the bed nucleus of the stria terminalis in the rat.

The destruction of the central amygdaloid nucleus (Ce), which contains a large group of neurons with leucine-enkephalin (L-ENK)-like immunoreactivity (L-ENKI), resulted in a marked ipsilateral reduction of these fibers in the bed nucleus of the stria terminalis (BST) suggesting that L-ENKI neurons in the Ce project ipsilaterally to the BST. This was supported by the finding that injection of biotin-wheat germ agglutinin into the BST labeled many neurons in the Ce. Simultaneous staining with antiserum showed that some of these neurons are L-ENKI. The L-ENKI fibers from the Ce reach the BST via two pathways; one from the venral amygdalofugal pathway (VA), which terminate in the ventral subdivision of the BST pars lateralis (BSTL), and the other from the stria terminalis (ST), which terminates in the lateral subdivision of the BSTL, because accumulation of L-ENKI structures appeared in the axons of these two systems on the amygdaloid side, transection or destruction of the ST alone caused only a slight reduction of ENKI fibers in the lateral subdivision of the BSTL ipsilaterally and transection or destruction of VA alone markedly reduced the number of L-ENKI fibers in the ventral subdivision of the ipsilateral BSTL. Thus, the VA L-ENKI fiber system is the major source of L-ENKI fibers in the ventral subdivision, while the ST L-ENKI fiber system is a minor source of the L-ENKI fibers in the lateral subdivision. The presence of an intrinsic L-ENKI system in the BST which may innervate the lateral subdivision was also suggested.

Afferent Pathways↗
PubMed1987

Distribution and origin of calcitonin gene-related peptide in the rat stomach and duodenum: an immunocytochemical analysis.

We studied the three-dimensional distribution of structures with calcitonin gene-related peptide-like immunoreactivity (CGRPI) in the rat stomach and duodenum, including the origins of these structures, using indirect immunofluorescence in both muscle strips and frozen sections. There was a very dense meshwork of CGRPI fibers in the circular and longitudinal muscle layers, and also in the myenteric and submucous plexuses of the stomach and duodenum. No CGRPI neurons were seen in the stomach, even in rats treated with colchicine; in the duodenum, there was a group of CGRPI cells in the myenteric and submucous ganglia. No regional differences were seen in the stomach and duodenum. We found by experimental manipulations that CGRPI fibers in the stomach were exclusively extrinsic in origin; some of such fibers in the duodenum were intrinsic in origin, though most were supplied by CGRPI cells outside the duodenum.

Animals↗