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Biomedical subjects

H Takagi

Publications and source records attributed to H Takagi.

At least 1,225 records · Page 68Linked to original sources
PubMed1981

Morphological study of noradrenaline innervation in the caudal raphe nuclei with special reference to fine structure.

Previous histofluorescence studies have demonstrated that the caudal raphe nuclei (CRa) of the rat, particularly the ventral portion (VCRa), contains a very high density of noradrenaline (NA) terminals and in the present study we attempted to elucidate the origins and free structure of the NA terminals in this region. The majority of NA terminals found in the VCRa originated from A1 and A3 NA neurons and disclosed that a small number of very strongly fluorescent fibers located along the blood vessels arise from the superior cervical ganglion (SGC). Electron microscopic analysis after potassium permanganate fixation demonstrated that the NA terminals originated from A1 and A3 NA neurons are connected with neuronal elements, while NA fibers from the SGC were identified among the vascular elements. Axodendritic contacts were found to be predominant among the synapselike contacts of NA terminals in this area.

Animals↗
PubMed1981

Distribution of somatostatin in the frog brain, Rana catesbiana, in relation to location of catecholamine-containing neuron system.

The distribution of somatostatin (SRIF)-immunoreactive structures in the central nervous system of the bull frog (both with and without treatment of colchicine) was studied, using the indirect immunofluorescence technique of Coons and co-workers (Coons, '58). SRIF-containing cells were observed in more than ten areas including the spinal cord. These SRIF-positive cells showed segmental distribution, in that SRIF-positive neurons were identified in various areas at various brain levels. An extensive network of SRIF-positive fibers was found in most parts of the central nervous system. The distribution of a catecholamine (CA)-containing neuron system in the frog brain is also presented in this study. The possible interactions between SRIF and CA neurons systems are briefly discussed.

Animals↗
PubMed1981

Topographic atlas of somatostatin-containing neurons system in the avian brain in relation to catecholamine-containing neurons system. I. Telencephalon and diencephalon.

The morphological organization of the somatostatin (SRIF)-positive neurons in the forebrain (telencephalon and diencephalon) of the warbling grass parakeet (Melopsittacus undulatus) was studied using the indirect immunohistochemical technique of Coons and co-workers ('58). In the telencephalon, a number of SRIF-positive neurons was detected in the lobus paraolfactorius, hippocampus, and paleostriatum. Furthermore, scattered SRIF-labeled cells were noticed in the area corticoidea dorsolateralis and area temporoparieto-occipitalis. A moderate density of immunoreactive fibers was found in the above areas. In addition, although the septal areas was devoid of SRIF-positive neurons, this area contained a moderate occurred in the following hypothalamic areas: (1) nucleus medialis hypothalami posterior, (2) lateral hypothalamus, and (3) mammillary nucleus. The bird hypothalamus also received a strikingly massive SRIF innervation. The heaviest concentration of SRIF-labeled fibers was detected in the medial eminence. Many SRIF-labeled fibers were also observed in other hypothalamic regions. Their locations roughly corresponded in many cases to the areas in which SRIF-positive neurons were disclosed. The overall distribution of the catecholamine system (CA) of the avian forebrain is also represented by means of histofluorescent technique. A possible interaction between SRIF and CA neurons systems is briefly discussed.

Animals↗
PubMed1981

Topographic atlas of somatostatin-containing neuron system in the avian brain in relation to catecholamine-containing neuron system. II. Mesencephalon, rhombencephalon, and spinal cord.

With the indirect immunofluorescence technique of Coon's and collaborators, overall distribution of the somatostatin (SRIF)-positive neurons system in the avian lower brain stem was explored. Numerous cell somata containing SRIF were identified in the interpeduncular nucleus and substantia grisea centralis (GCT) at the level of the nucleus nervi trochlearis. Furthermore, a moderate number of SRIF-positive neurons were seen in the tectum opticum, nucleus tractus solitarii, and spinal cord. Scattered labeled cells were noticed in the rhombencephalon. A dense network of SRIF-positive fibers was distributed widely in the lower brain stem of birds. Their locations corresponded in many cases to the areas where SRIF-positive neurons were found. The present study also presents the distribution of the catecholamine (CA) neuron system in the avian lower brain stem. Possible interactions between SRIF and CA neurons systems are briefly discussed.

Animals↗
PubMed1981

Comparative anatomy of the distribution of catecholamines within the inferior olivary complex from teleosts to primates.

The distribution of catecholamine (CA) in the inferior olivary complex (IO) of various vertebrate (from fish to monkey) was investigated by means of the histofluorescence technique. In addition, using rats, a further attempt was made to elucidate the origins of CA in the IO. The IO of the lower vertebrates (from fish to birds) was in general poorly innervated by the CA neuron system. IO in the lower mammals, such as insectivora and bats, contained only a few CA nerve terminals, while that in the higher mammals such as rat, guinea pig, rabbit, cat, and monkey revealed quite a number. In these animals, species-species patterns of CA nerve terminals were found. In the rat, the highest concentration was observed in the dorsal lamella of the principal nucleus and in guinea pig ventral lamella. In the rabbit and cat, maximum CA nerve terminals were detected in the dorsal accessory nucleus, while in the monkey, they were detected in the medial accessory nucleus. The retrograde tracer technique of horseradish peroxidase (HRP) suggested that the main source of the abundant CA terminals in IO of the rat might be A1, A2, and A3 noradrenaline neurons, though not locus coeruleus and not dopaminergic ones.

Animals↗
PubMed1981

Experimental immunohistochemical studies on the amygdalofugal peptidergic (substance P and somatostatin) fibers in the stria terminalis of the rat.

The amygdalofugal substance P (SP) and somatostatin (SRIF) neuron systems in the stria terminalis (ST) were investigated by means of the indirect immunofluorescence technique of Coons. SP- and SRIF-positive cells were mainly located in the area (Amc) between the central (ac) and medial (am) amygdaloid nuclei. Some extended medially into the am and laterally into the ac. Destruction of the Amc resulted in a marked reduction of SP- and SRIF-positive fibers in the ST. Furthermore, a substantial decrease in SP-positive fibers was seen in the dorsal part of the bed nucleus of the ST (stb), there was a small decrease in the SP-positive fibers in the lateral hypothalamus (LH), a significant decrease in the SRIF-positive fibers in the lateroventral part of the anterior hypothalamic nucleus (lvAH), and a small decrease in the SRIF-positive fibers in the LH. These facts indicate that the origins of a number of SP- and SRIF-positive fibers are the Amc and that the amygdalofugal SP pathway in the ST innervates stb and LH and the amygdalofugal SRIF pathway in the ST projects to lvAH and LH.

Amygdala↗
PubMed1981

Mechanism of kyotorphin-induced release of Met-enkephalin from guinea pig striatum and spinal cord.

The characteristics of kyotorphin (Tyr-Arg)-induced release of Met-enkephalin from the striatum and the spinal cord of guinea pig were determined by superfusing the slices in vitro and then carrying out radioimmunoassays. Depolarization by 50 mM K+ induced a marked release of Met-enkephalin-like immunoreactivity. The potassium-induced release of Met-enkephalin was calcium-dependent. In preparations from a striatum, the addition of kyotorphin to the superfusion medium produced a concentration-dependent increase in Met-enkephalin. The kyotorphin-induced release of Met-enkephalin was calcium-dependent and was abolished by tetrodotoxin. Similar effects of kyotorphin were seen in the spinal cord preparations. Electrical field stimulation of the striatal slices at a frequency of 10 Hz also evoked significant and calcium-dependent increases in the release of Met-enkephalin and markedly enhanced the kyotorphin-induced release of Met-enkephalin, as compared to the controls not given field stimulation. These results suggest that kyotorphin depolarizes the so-called enkephalinergic neurons and releases Met-enkephalin from nerve terminals. This effect of kyotorphin may be a possible mechanism related to the manifestation of analgesia.

Animals↗
PubMed1981

Regional distribution of substance P-like immunoreactivity in the frog brain and spinal cord: immunohistochemical analysis.

With the indirect immunofluorescence technique of Coons, the overall distribution of the substance P (SP)-positive neuron system in the frog brain and spinal cord was explored. SP-positive cells were observed in more than ten areas, such as olfactory bulb, amygdaloid complex, septal area, bed nucleus of hippocampal commissure, hypothalamic periventricular zone, dorsal and ventral thalamus, infundibulum, torus semicircularis, optic tectum, the area dorsal to the interpeduncular nucleus, central gray matter of the mesorhombencephalon, and raphe region, etc. A dense network of SP-positive fibers was also widely distributed in the frog brain and spinal cord. SP-positive fibers were roughly divided into two types. One consisted of very fine SP-positive fibers and gave the region a diffuse appearance. The area medial to n. Bellonci, interpeduncular nucleus, n. isthmi, and optic tectum contained this type of SP-positive fibers. The other one consisted of clearly distinguishable varicose fibers. A number of SP-positive fibers located in the amygdaloid complex, striatal complex, hypothalamus, central gray matter of the mesorhombencephalon, trigeminal spinal nucleus, and posterior horn of the spinal cord belonged to this category. The functional role of the SP-positive neuron system in the central nervous system is also briefly discussed.

Animals↗
PubMed1981

New somatostatin-containing sites in the diencephalon of the neonatal rat.

Using an immunohistochemical technique, the present study demonstrated several new somatostatin-containing sites in the diencephalon of neonatal rats which have not been reported in adult animals. These areas are the area just lateral to the commissura posterior, the area between the optic tract and capsula interna, pars retrolenticularis and n. peripeduncularis.

Animals↗
PubMed1981

Somatostatin-like immunoreactivity in the facial, glossopharyngeal and vagal lobes of the carp.

A large number of somatostatin (SRIF)-containing structures was demonstrated in the vagal and glossopharyngeal lobes of the carp by means of the indirect immunofluorescent method. The present study further showed that the facial lobe is devoid of these structures. These facts indicate that SRIF may have an important role in relaying viscerosensory information from the vagal and glossopharyngeal nerve but not from the facial nerve.

Animals↗
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

Rapid enlargement of ventricles within seven hours after head injury.

We report a case of acute enlargement of the ventricles within 7 hours after head injury that was documented by repeated computerized tomography. It is suggested that the pathophysiological mechanism for this rapid enlargement of ventricles may be due to the raised intracranial pressure (ICP) that results from obstruction of cerebrospinal fluid pathways by subarachnoid hemorrhage, in addition to the elevation of ICP aggravated by frequent focal convulsive seizures.

Brain Concussion↗