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Biomedical subjects

M Tohyama

Publications and source records attributed to M Tohyama.

At least 577 records · Page 32Linked to original sources
PubMed1981

Demonstration of a substance P-like immunoreactivity in retinal cells of the rat.

The distribution of substance P (SP)-like immunoreactivity in the rat retina was investigated by immunohistochemistry. SP-positive cells were found throughout the retina. The majority of them were located in the proximal portion of the inner nuclear layer and the processes from these cells directed to the inner plexiform layer where they ramified, suggesting that SP-positive cells located in this region probably are amacrine cells. Few SP-positive cells were seen within the ganglion cell layer. They were considered displaced amacrine cells.

Animals↗
PubMed1981

Somatostatin in the auditory system of the rat.

The present study clearly disclosed that the auditory system of the neonatal rat contains a large number of somatostatin (SRIF)-positive structures. Among them, n. cochlearis dorsalis and ventralis, n. ventralis lemnisci lateralis and n. parabrachialis colliculi inferioris contain huge collections of SRIF-positive neurons. Furthermore, the rat auditory system in general contains a number of SRIF-positive fibers.

Animals↗
PubMed1981

On the afferent projections from some meso-diencephalic nuclei to n. raphe magnus of the rat.

Afferent sources from meso-diencephalon to n. raphe magnus (RM) were examined by the HRP method. Following HRP injection into RM, HRP-labeled cell clusters occurred in: (1) n.linealis rostralis; (2) ventrocaudal part of n.parafascicularis; (3) zona incerta; and (4) midbrain reticular formation. As a rule, the axons from (1) and (4) mainly terminate within RM, while those from (2) and (3) seem to project to the inferior olive (IO) as well as RM. The functional significance of these nuclei is briefly discussed.

Afferent Pathways↗
PubMed1981

Experimental and morphological studies of te noradrenaline innervations in the nucleus tractus spinalis nervi trigemini of the rat with special reference to their fine structures.

An attempt was made to elucidate the origins and fine structure of the noradrenaline (NA) terminals in the nucleus tractus spinalis nervi trigemini (Vsp) of the rat. The present study revealed that the NA in the Vsp is supplied from two NA neuron systems; bilateral locus coeruleus (LC) and medullary NA neuron group, on the grounds that: (1) two types of fluorescent fibers (fine and coarse) were identified in the Vsp; and (2) HRP injected in to the Vsp resulted in labeling of neurons of the bilateral LC and bulbal NA areas, particularly the ipsilateral A1 area. The fine structure of the NA terminals in the Vsp was investigated by a modified potassium permanganate fixation method. The NA terminals in this area contained a number of small cored vesicles together with a small number of large cored vesicles. The most frequent feature of the NA terminals found in this area wa axo-dendritic contact. A lesser, but still substantial, number with axo-axonic contact were also noticed, in connection with which, it should be stressed that the non-NA terminals examined in this study were always presynaptic in structure, since the clear vesicles found in the non-NA terminals sometimes aggregated close to the contact membrane, where some of them fused or touched the membrane. As the dendrites showing a close relationship with the NA terminals were relatively large in size and contained a number of cytoplasmic organelles, these dendrites were assumed to be the proximal segments. At the contact zone, although no typical synaptic specialization was identified, the following profiles suggestive of synaptic-like contact were demonstrated: (1) somewhat dense material between contact membranes (intersynaptic filaments); (2) a slight accumulation of the dense materials adjacent to the postcontact membrane; (3) disarrangement of the contact membranes and enlargement of the space between these membranes; and (4) aggregation of the synaptic vesicles at the contact membrane with some of them fusing or touching the contact membrane.

Animals↗
PubMed1981

Ascending and cerebellar non-serotonergic projections from the nucleus raphe magnus of the rat.

Non-serotonergic ascending and cerebellar projections of rat nucleus raphe magnus (RM) were disclosed using the horseradish peroxidase technique. The ascending bundle rose form rostral RM and was divided into two components; one ascended in raphe regions and the other in reticular formation. The former on innervated n. raphe dorsalis, etc., and the latter n. parafascicularis, zona incerta, etc. On the other hand, the axons innervating neocerebellum originated exclusively from caudal RM.

5,6-Dihydroxytryptamine↗
PubMed1981

Localization of vasoactive intestinal polypeptide and neurotensin immunoreactivities in the avian retina.

The distribution of vasoactive intestinal polypeptide (VIP)- and neurotensin (NT)-like immunoreactivities in the chicken retina was investigated by immunohistochemistry. VIP- and NT-positive cells were found throughout the chicken retina. The majority of them were located in the proximal portion of the inner nuclear layer and the processes from these cells directed to the inner plexiform layer where they ramified, suggesting that VIP- and NT-positive cells located in this region probably are amacrine cells.

Animals↗
PubMed1980

Ascending components of the medial forebrain bundle from the lower brain stem in the rat, with special reference to raphe and catecholamine cell groups. A study by the HRP method.

The afferent connection of the medial forebrain bundle (MFB) arising from the lower brain stem have been investigated by means of horseradish peroxidase (HRP) with sensitive substrate, the injection was made iontophoretically into MFB at various levels. After injection of HRP into MFB, a significant number of HRP-labeled neurons were observed in the following structures of the lower brain stem: (1) raphe nuclear group, (2) locus coeruleus, (3) n. laterodorsalis tegmenti, (4) parabrachial area, (5) A1, A2, A4, A5 and A7 areas where noradrenaline-containing neurons were disseminated, (6) A8, A9 and A10 areas which contain dopamine neurons, (7) surrounding area of the fasciculus longitudinalis medialis at the level of the n. propositus hypoglossi, (8) n. prepositus hypoglossi and (9) mesencephalic gray matter. As a rule, the ascending projections are ipsilateral and course in the medial part of MFB. Regarding the raphe nuclei, we have demonstrated that the caudal raphe nuclei, such as n. raphe magnus and obscurus (but not n. raphe pallidus), also send their axons to the hypothalamus. Particularly, the axons of n. raphe magnus ascend in MFB to reach the level of the preoptic or anterior septal areas. Furthermore, in accordance with previous reports, HRP-labeled cells were also identified in the n. raphe dorsalis, centralis superior and pontis, respectively. It should be further noted that labeled cells appeared in the n. linearis caudalis. In addition, the present study indicates a number of non-aminergic cell groups as sources of ascending mfb fibers. On the whole, the present study further clarified the organization of the components of the MFB ascending from the lower brain stem, and provided some additional anatomical substrates for the physiology of the control of the forebrain by the lower brain stem neurons.

3,3'-Diaminobenzidine↗
PubMed1980

Fine structure of noradrenaline nerve terminals in the dorsomedial portion of the nucleus tractus solitarii as demonstrated by a modified potassium permanganate method.

Fine structure of the noradrenaline (NA) nerve terminals in the dorsomedial portion of the nucleus tractus solitarii (NTS) was investigated by glyoxylic acid-potassium permanganate fixation method. The NA nerve terminals in this area contained a large number of small cored vesicles (SCV) (about 400-600 A in diameter) together with a few large cored vesicles (LCV) (about 1000 A in diameter). The most frequent feature of NA nerve terminals observed in this area was axo-dendritic contact. An axo-axonic contact between NA and non-NA terminals was also occasionally identified, while no axo-somatic contact was found in this area as far as examined. At the contact zone between NA terminals and other neuronal elements, the following profiles suggestive of synapse-like contact were identified: 1) somewhat dense material between contact membranes (intersynaptic filaments); 2) a slight accumulation of dense material adjacent to postcontact membranes; 3) disarrangement of contact membranes and enlargement of the space between these membranes; 4) aggregation of SCV and LCV to contact membranes. Finally it should be emphasized that NA nerve terminals often made a neuronal cluster or rosette with other neuronal elements, suggestive of a complicated role of NA on NTS function.

Animals↗
PubMed1980

Ascending and descending components of the medial forebrain bundle in the rat as demonstrated by the horseradish peroxidase-blue reaction. I. Forebrain and upper brain stem.

The ascending and descending components of the medial forebrain bundle (MFB) were investigated by means of horseradish peroxidase (HRP) with a sensitive substrate. The HRP was injected iontophoretically into the MFB at various levels from the anterior commissure to the posterior hypothalamus. In order to prevent the diffusion of HRP to other brain areas, a double micropipette system was used. The descending components of the MFB are derived from (1) the anterior cingulate area, infra- or prelimbic area, and sulcal cortex, (2) the lateral septal nucleus and diagonal band, (3) the bed nucleus of the stria terminalis, (4) the paraventricular nucleus (5) the substantia innominata, (6) the amygdaloid complex (AM), (7) the ventromedial (VM) and dorsomedial (DM) hypothalamic nuclei, (8) the entopeduncular nucleus and (9) nucleus periventricularis stellatocellularis. The ascending components of the MFB originate in: (1) the medial preoptic nucleus, (2) the nucleus periventricularis stellatocellularis and rotundocellularis, (3) the posterior hypothalamic nucleus, (4) the parafascicular nucleus, (5) the ventral premammillary nucleus, (6) the substantia grisea periventricularis, (7) the lateral habenular nucleus, (8) the VM and DM, (9) the paratenial nucleus, (10) the AM and (11) the arcuate nucleus.

Animals↗
PubMed1980

Topographic organization of the projection from the forebrain subcortical areas to the hippocampal formation of the rat.

Using the technique of iontophoretic microinjection of horseradish peroxidase, the present study disclosed the complexity and high degree of the topographic organization in the forebrain subcortical afferents to the different regions of rat hippocampus, e.g. diagonal band, posterior (PH), dorsomedial and rostral lateral hypothalamic nuclei chiefly project to the rostrodorsal part (DRA) and caudal gyrus dentatus including CA3, the supramammillary area predominantly to the rostroventral area (VRA), the area lateral to PH to the DRA and VRA, substantia innominata and some thalamic nuclei (n. reuniens, n. lateralis thalami, n. anterior ventralis and n. lateralis thalami pars posterior) to the dorsal subiculum, respectively.

Animals↗
PubMed1979

Spinal projections from the lower brain stem in the cat as demonstrated by the horseradish peroxidase technique. II. Projections from the dorsolateral pontine tegmentum and raphe nuclei.

The descending projections to the spinal cord arising from the dorsolateral pontine tegmentum and brain stem raphe nuclei have been investigated by means of the horseradish peroxidase (HRP) technique. Particular attention was taken to clarify the cells of origin and the funicular trajectory of these spinal projections. After injections of HRP into the spinal cord, a significant of HRP labeled neurons were observed in the following dorsolateral pontine tegmental structures: (1) an area ventral to the nucleus cuneiformis; (2) principal locus coeruleus; (3) locus coeruleus a; (4) locuse subcoeruleus; (5) Kölliker-Fuse nucleus; and (6) nucleus parabrachialis lateralis. As a rule, the projections are ipsilateral and descendaphe-spinal projections, we have demonstrated that the nucleus raphe dorsalis also sends axons to the cervical segment of the spinal cord. Furthermore, in accord with previous reports, HRP labeled cells were also identified in the nucleus raphe magnus, pallidus and obscurus, but not in the nucleus raphe centralis superior and pontis. On the whole the present study further clarified the organization of spinal projections from the dorsolateral pons and raphe nuclei and provided some additional anatomical data for the physiology of the tegmentospinal and raphe-spinal projections.

Animals↗