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S Daikoku

Publications and source records attributed to S Daikoku.

At least 19 recordsLinked to original sources
PubMed1992

Neuronal associations in the rat suprachiasmatic nucleus demonstrated by immunoelectron microscopy.

The synaptic associations of neurons in the suprachiasmatic nucleus (SCN) of rats were examined by single immunolabeling for somatostatin (SRIH) and arginine vasopressin (AVP), and double immunolabeling for SRIH plus AVP and vasoactive intestinal polypeptide (VIP) plus AVP. Single immunolabeling showed that SRIH neurons, which displayed some somatic and dendritic spines, formed synaptic contacts with immunonegative and positive axon terminals. AVP neurons also formed synaptic contacts with both immunonegative and positive axon terminals. The immunonegative terminals contained small, spherical clear vesicles or flattened clear vesicles. A few immunopositive AVP fibers made synapses with immunonegative somatic or dendritic spines. Double immunolabeling showed synaptic associations between SRIH axons and AVP cell bodies or dendritic processes, and between AVP axons and the somata or dendrites of SRIH neurons. These findings suggest a reciprocal relation between the two types of neurons. Synaptic contacts between AVP neurons and VIP axon terminals were also demonstrated. Previously, we found synapses between SRIH axons and VIP neurons. Thus SRIH neurons appeared to regulate AVP and VIP neurons. On the basis of these findings, two possible oscillation systems of the SCN are proposed.

Animals↗
PubMed1992

Synaptic associations between oxytocin-containing magnocellular neurons and neurons containing corticotropin-releasing factor in the rat magnocellular paraventricular nucleus.

In the paraventricular nucleus (PVN) of the rat hypothalamus, we determined synaptic associations between oxytocin (OXT)-containing magnocellular neurons and parvocellular neurons containing corticotropin-releasing factor (CRF) by using a double immunolabeling technique in 7 animals. In single vibratome sections of the hypothalamus, immunoreactive CRF and OXT were labeled with silver-gold particles and diaminobenzidine (DAB) chromogen, respectively. By light microscopy CRF-containing fibers appeared to be black dots, some of which encircled magnocellular perikarya labeled with brown DAB chromogen in the PVN. By electron microscopy we discriminated OXT neurons having fine DAB-chromogen particles distributed throughout the cytoplasm and on large secretory granules from CRF neurons having dense coarse particles of silver-gold. Occasional CRF axons terminated on perikarya or dendritic processes of OXT neurons, making synaptic contacts. The terminals which were characterized by having clusters of small clear vesicles and a few dense core vesicles showed equal thickenings of pre- and postsynaptic membranes at the synaptic junctions.

Animals↗
PubMed1992

Blood vessels and immunoreactive substance P-containing nerve fibers in rat skin treated topically with clobetasol propionate, a corticosteroid.

After applying topically a cream (0.1 ml) containing corticosteroid (clobetasol propionate), on rat back skin, we examined the morphological alterations of blood vessels, substance P-containing nerve fibers, and cutaneous mast cells. After 3, 6, 10, 15, 30, and 60 min and 4 h, the skin treated was cut out with a sharp knife after killing the animals. The skin pieces were processed into conventional histological sections cut vertically and examined by staining immunohistochemically with anti-substance P serum, by staining with toluidine blue for mast cell granules, and by estimating morphometrically the average areas of vascular cavity and the number of substance P fibers in the dermis. In the dermis and subcutaneous tissue of untreated skin, we found many immunoreactive SP-containing nerve fibers and mast cells in close association. Three to ten min after the treatment, the average area of the vascular cavities steadily increased, and SP-positive fibers became less frequent in the dermis. In concomitant with those events, cutaneous mast cells discharged their granules. Thereafter, the average area of vascular cavities gradually decreased to a minimum at 4 h after the treatment. In contrast, both SP-containing fibers and mast cells reestablished their initial states after the same duration.

Administration, Topical↗
PubMed1992

Pathogenesis, treatment and prognosis of impending myocardial infarction and early post-infarction angina--relation between ST-segment shift during myocardial ischemia and the pathogenesis.

We studied 141 patients to evaluate the pathogenesis and clinical picture of high-risk unstable angina (UA), designated as impending myocardial infarction (IMI) in this study, or severe early post-infarction angina (PIA). IMI and PIA were diagnosed when chest pain appeared at rest and lasted 15 min or more despite extensive pharmacological therapy during hospital stay among consecutive 510 patients with UA. All patients underwent coronary angiography urgently within 72 h after chest pain, and were divided into 2 subgroups according to ST segment shifts during chest pain. In IMI, 42 patients with ST depression had higher incidences of prior myocardial infarction (MI), worsening UA, multivessel disease and complex lesions such as eccentric irregular lesion or ulceration. On the contrary, in 44 with ST elevation, new onset UA, single vessel disease and coronary thrombus (CT) were dominant. In PIA, 32 patients with ST elevation revealed higher incidences in Q wave MI, ST elevation at the MI onset, single vessel disease and CT, compared to 23 with ST depression who showed a high proportion of complex lesions. Thus, it was evident that there was a common link between the pathogenesis of IMI and PIA. The therapeutic options were also different in the groups according to ST segment shift. We conclude that ST segment shifts during chest pain may be useful for determining the pathogenesis and clinical features of high-risk UA.

Angina, Unstable↗
PubMed1992

Light stimulation of the hypothalamic neuroendocrine system.

This paper demonstrates that, in the mediation of light, the suprachiasmatic nucleus (SCN) functionally associates with the anterior periventricular and parvocellular paraventricular neuron systems in rats. Intact rats (group 1) and rats undergoing a hemicomplete cutting of the SCN (group 2) were housed in a dark room (2-3 weeks) and killed after an exposure to light for 10, 30 or 60 min. Other intact animals (group 3) kept in a dark room (2 weeks) were exposed to light for 10 min, then stored 60 min in the dark room, and killed in darkness. The SCN, anterior periventricular nucleus, and parvocellular paraventricular nucleus were examined immunohistochemically using antisera for vasoactive intestinal polypeptide (VIP), arginine vasopressin, somatostatin, rat corticotropin releasing factor (rCRF), and c-fos protein. In comparison with animals kept in darkness, animals exposed for 10 and 30 min to light indicated a remarkable reduction of VIP immunoreactivity in the SCN and some increase of CRF immunoreactivity in the parvocellular paraventricular nucleus. The diminution of VIP immunoreactivity did not occur in the isolated SCN of group 2 animals. In group 3, a 10 min-light exposure induced a remarkable enhancement of nuclear c-fos immunoreactivity in neurons in the ventrolateral region of the SCN, in the anterior periventricular nucleus, and in the parvocellular paraventricular nucleus, most strongly in the SCN. Double immunolabeling methods have shown that VIP, somatostatin, and CRF neurons in the respective nuclei were c-fos positive.

Animals↗
PubMed1992

[A case of unstable angina pectoris associated with an active phase of polymyositis].

We report a case of unstable angina in an active phase of polymyositis. A 51 year-old man was admitted with a diagnosis of polymyositis and unstable angina with ST elevation on prolonged rest chest pain. Rest anginal attack which had been refractory to conventional antianginal medications was controlled by high dose of glucocorticosteroid. Electrocardiography revealed multifocal premature ventricular contraction. Since silent ischemia on exercise persisted, percutaneous transluminal coronary angioplasty (PTCA) was performed on a stenotic lesion in the left anterior descending artery. Since there was recurrent anginal attack, re-PTCA was carried out at the same site. He was discharged in a good condition. This case is considered to be associated with cardiac involvement of polymyositis because of ventricular arrhythmia, persistent increased serum levels of CPK-MB, and the marked benefits of corticosteroid against unstable angina. In addition, clinical manifestations, coronary arteriographic findings, and increased plasma levels of thrombin-antithrombin III complex suggest that cardiac involvement in polymyositis accelerates intracoronary thrombus formation and/or coronary spasm.

Angina, Unstable↗
PubMed1991

Spatial-temporal appearance of developing immunoreactive TRH neurons in the neuroepithelial wall of the diencephalon.

Using an anti-pro-thyrotrophic hormone-releasing hormone (TRH) serum for immunohistochemical analysis, we examined the ontogenesis of TRH-producing neurons in the rat diencephalon, and distinguished three waves in the neurogenesis corresponding to the time and place of their origin. The first wave started on day 12.5 of embryonic age (E12.5); the neurons appeared within the neuroepithelium in both the anterior and posterior walls of the optic recess. These cells then migrated anteriorly into the marginal layer of the developing preoptic area (group 1 cells) and posteriorly into the hypothalamus (group 2 cells). The second and third waves occurred on E13.5-14.5 and E16.5-17.5, respectively. We named the cells that appeared in the neuroepithelium of the anterior portion of the hypothalamus as group 3 and 5 cells, and those in the posterior portion as group 4 and 6 cells. Group 1 and 3 cells generated the lateral and medial preoptic TRH neurons, and group 2 and 4 cells generated the cells in the lateral hypothalamic nucleus. Group 6 cells were involved in the development of the dorso-medial hypothalamic nucleus. Group 5 cells gave rise to the hypophysiotrophic secretory neurons in the parvocellular paraventricular nucleus. The cells derived from each cell group showed distinct morphological characteristics. These findings suggest that the ventricular wall of the hypothalamus is protomapped in a spatial-temporal manner to generate TRH neurons with distinct functional properties.

Amino Acid Sequence↗
PubMed1991

Hypophysiotrophic TRH-producing neurons identified by combining immunohistochemistry for pro-TRH and retrograde tracing.

To determine hypophysiotrophic thyrotropin-releasing hormone (TRH)-producing neurons in the rat hypothalamus, we employed a combination of the immunohistochemistry for TRH prohormone (pro-TRH) and the retrograde tracing of neurons that project to the median eminence (ME) by injecting biotinylated wheat germ agglutinin (WGA) into the ME. In intact rats, immunoreactive pro-TRH-positive neurons occurred in the parvicellular paraventricular nucleus (parvi-PVN), basal part of the anterior and lateral hypothalamus, perifornical area and dorsomedial nucleus, especially accumulating in the parvi-PVN. Twenty-four hours after injection of the WGA into the middle portion of the ME, we found neurons that incorporated the lectin in the anterior periventricular area, the PVN, and the arcuate nucleus. When we examined serial sections consecutively stained with anti-WGA, anti-pro-TRH, and anti-WGA, most of the pro-TRH-labeled neurons in the medial parvi-PVN and a part of the neurons in the anterior periventricular area and in the anterior, lateral, and dorsal parvi-PVN appeared to incorporate WGA. These neurons may correspond with the hypophysiotrophic TRH-synthesizing neurons in the rat hypothalamus.

Amino Acid Sequence↗
PubMed1991

Existence of mutual synaptic relations between corticotropin-releasing factor-containing and somatostatin-containing neurons in the rat hypothalamus.

Light microscopic studies of vibratome sections, which were double-immunostained for corticotropin-releasing factor (CRF) and for somatostatin (SS), suggested the presence of reciprocal synaptic relations between neurons containing immunoreactive (ir) CRF and those containing ir SS in the parvocellular paraventricular nucleus (parvo-PVN) and in the anterior periventricular area (APV) of the rat hypothalamus. In the sections the peptides included in neuronal fibers were labeled black with silver-gold particles, and the peptides included in neuronal cell bodies were labeled brown with diaminobenzidine (DAB). Thereby the brown cell bodies appeared to be surrounded by several black nerve terminals. In electron microscopic studies, the labeling was mostly performed in reverse fashion, because of the convenience for observing the ultrastructural details of the nerve terminals. The neuroplasm of the postsynaptic perikarya and dendrites was labeled with gold-coated silver grains, while the presynaptic axonal terminals were shown with scattered DAB particles. Granular structures in the perikarya or axonal terminals were labeled distinctively. The synaptic morphology appeared to be either symmetric or asymmetric connections. Then we found synaptic connections between presynaptic ir SS containing fiber terminals and postsynaptic ir CRF containing perikarya in the parvo-PVN, and those ir CRF containing fiber terminals and ir SS containing perikarya in the APV. The existence of such a reciprocal association between CRF and SS neurons may suggest that these neuronal systems intervene among different functional systems in the hypothalamus.

Animals↗
PubMed1991

Further evidence of the presence of rat embryonic hypothalamic factors that induce the differentiation of gonadotrophic hormone-releasing hormone-containing secretory neurons.

We examined the presence of factor(s) in the embryonic medial basal hypothalamus (MBH) that may influence nasal placode (NAP)-derived luteinizing hormone-releasing hormone (LHRH) neurons in determining their secretory phenotype. In this study, we performed organotypic culture and transplantation of the NAP from 12.5-day-old embryos of rats and vomeronasal organ (VNO) from 14.5-day-old embryos. Surgical operations, however, were performed on 16.5-day-old embryos. The NAP and VNO were cultured singly or with the MBH obtained from the embryos of the same age and, further, in a medium with a nerve growth factor or fibroblast growth factors. Although LHRH neurons were derived from the NAP and VNO in all the cultures, judging from numbers and cellular morphologies, the MBH was most effective. The VNO was transplanted into the third ventricle of adult female rats singly or with the cerebral cortex, the mesencephalon-myelencephalon complex, or the MBH from 14.5-day-old embryos. All the grafts gave rise to LHRH neurons, but the number of the neurons was far greater in the grafts cotransplanted with the MBH, in which the neurons projected long processes to blood capillaries and formed neurovascular complexes, the feature of which may suggest the occurrence of the secretory activity in the fibers. The animals were examined 5 days after the surgical operations. In rhinoectomized embryos, LHRH neurons were distributed throughout the brain in the same pattern as found in intact rats, showing normal cellular morphology. In the encephalectomized rats, immunoreactive LHRH cells were present only in the terminal ganglia. These findings indicate that the embryonal MBH has a factor (s) that is essential to the development of secretory LHRH neurons.

Animals↗
PubMed1991

Development of the hair in the rat: in vivo and in transplanted tissue.

Differentiation of the hair was examined in the head skin of rat embryos aged from days 12.5 to 18.5 of gestation. In 12.5-day-old embryos, the skin consisted of single layered epidermis and underlying loose connective tissue. On day 17.5 of gestation, the epidermis appeared to have a two or three layered epithelium, and the subepidermal connective tissue gave rise to an overlying dense tissue, into which blood capillaries arose from the deeper layer. The epidermis showed partial thickenings, where basal cells were arranged perpendicular to the surface of the epidermis. Beneath the epidermal thickenings, a number of connective tissue cells appeared to have accumulated and occasionally were accompanied by blood capillaries. In sequential development of the skin, the thickenings protruded as cords to the underlying dermal tissue and formed hair follicles covered with a connective tissue sheath. Skin obtained from 12.5-day-old embryos was transplanted singly or with cerebral cortex into the third ventricle of adult male rats. Thirty days after the transplantation, hairs and sebaceous glands had developed from the grafted skin. Hair growth tended to be more prominent in the cotransplanted skin grafts. However, no nerve fibers immunoreactive for substance P or calcitonin gene-related peptide (CGRP) were found in the grafted skin, although these fibers appeared in the dermis at the end of gestation in vivo. These results showed that the skin of 12.5-day-old embryos was able to induce hair growth in the third ventricle without accompanying peripheral neuronal fibers or blood capillaries, although the effects of connective tissue cells could not be ruled out.

Animals↗
PubMed1991

Substance P-containing neurons innervating LHRH-containing neurons in the septo-preoptic area of rats.

Neuroanatomical attempts have been made to determine the synapses between luteinizing hormone-releasing hormone (LHRH)-containing neurons and substance P (SP)-containing neurons in the hypothalamus of female rats. Wheat germ agglutinin was injected into the septo-preoptic area (SPA) and found to be incorporated into certain SP-containing neurons within the arcuate nucleus and the ventrolateral portion of the anterior hypothalamus. Hence, we used a preembedding double immuno-staining technique in demonstrating LHRH and SP neurons in the SPA. In light-microscopic preparations LHRH was labeled with 3,3'-diaminobenzidine tetrahydrochloride (DAB) as chromogen while SP was labeled with silver-gold particles; brown LHRH cells appeared to be surrounded by black silver-gold dots. In electron-microscopic preparations, the labelings for LHRH and SP were made reversely; SP was localized with DAB chromogen, and SP-containing axonal terminals appeared to make synaptic contacts on silver-gold-labeled LHRH cell bodies and dendritic processes. The terminals contained numerous small clear vesicles and some large dense-cored vesicles, and the synaptic membrane specialization appeared to be symmetric and asymmetric. These findings indicate that certain SP neurons existing in the arcuate nucleus and the ventrolateral portion of the anterior hypothalamus may project fibers to make synaptic contact with LHRH neurons in the SPA in the rat.

Animals↗
PubMed1991

Immunohistochemical localization of glucocorticoid receptors in anterior pituitary cells of rats.

Adenohypophysial cells having a glucocorticoid receptor were immunohistochemically determined in rats. For detecting the presence of the glucocorticoid receptor, we used the monoclonal antibody for a glucocorticoid receptor (BuGR-2), and immunohistochemically examined the phenotypes of the cells that exhibited BuGR-2-immunoreactivity. The immunoreaction for the glucocorticoid receptor was confined to the nuclei of the majority of corticotrophs (70%) and of some somatotrophs in intact animals. Following adrenalectomy, all corticotrophs became significantly hypertrophic, losing their immunoreactivity for the glucocorticoid receptor. In contrast, somatotrophs that had also lost the immunoreactivity for the glucocorticoid receptor in the nuclei greatly diminished in size. Intraperitoneal administration of corticosterone was performed in adrenalectomized animals to supplement glucocorticoids. This treatment restored BuGR-2-immunoreactivity in the nuclei of some corticotrophs. In intact rats, immunolabeled corticotrophs were classified into two types, stellate and polyhedral. However, the immunoreaction for the glucocorticoid receptor was equally evident in the cell nuclei of these different types of cells. It is concluded that, in rats, both corticotrophs and somatotrophs are target cells of glucocorticoids, although these cell types display opposite growth responses to the removal of glucocorticoids.

Adrenalectomy↗
PubMed1991

[Clinical and anatomical features of acute myocardial infarction associated with double rupture of the interventricular septum and ventricular free wall].

Four patients with acute myocardial infarction (MI) complicating double rupture; interventricular septum and ventricular free wall ruptures, were studied. All patients had histories of hypertension, and pre-infarction angina pectoris of short duration less than 8 days without previous MI. The sites of infarction were anteroseptal in 2 patients and inferoposterior in the other 2. Only one case was complicated with mild pump failure (Killip class II). Blood pressure was adequately controlled after the onset of MI in all patients. Interventricular septal rupture occurred between 2 and 10 days after the onset of MI. Free wall rupture occurred between 2 and 22 days after MI. Types of free wall ruptures were oozing in 2 patients and blow-out in the other 2. Surgical repair was performed in 2 patients with the oozing type rupture, who however died soon after surgery. The autopsy findings were as follows: 3 patients had left ventricular free wall ruptures and one had right ventricular free wall rupture. One of the patients with left ventricular free wall rupture showed a secondary rupture of a pseudo-ventricular aneurysm. Postmortem coronary angiograms revealed 3 patients with single-vessel disease and one patient with double-vessel disease, indicating that coronary arterial lesions and complicated heart failure were not severe in these 4 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Immunohistochemical evidence for synaptic connections between neuropeptide Y-containing axons and periventricular somatostatin neurons in the anterior hypothalamus in rats.

By employing a pre-embedding double immunolabeling technique, we examined light and electron microscopically synaptic associations between neuropeptide Y (NPY)-containing axons and somatostatin (SRIH)-containing neurons in the anterior periventricular area (APV) of the rat hypothalamus. For light microscopy, the immunoreactions for NPY and SRIH were visualized with silver-gold and diaminobenzidine (DAB), respectively, and the reverse labeling was used for electron microscopy. Light microscopy disclosed many brown SRIH perikarya surrounded by several black beads of NPY fibers in the APV. In electron microscopy, immunoreactive SRIH neurons revealed silver-gold particles scattered throughout the cytoplasm and accumulated in the Golgi area and the secretory granules. SRIH perikarya and dendritic processes indicated synaptic associations with DAB-labeled NPY fiber terminals and immunonegative fibers. NPY presynaptic terminals possessed numerous small clear vesicles and a few dense core vesicles; vesicular membranes and cores were labeled with DAB chromogen. Both the pre- and postsynaptic membranes were thickened equally to be a symmetric synapse. These findings suggest that NPY neurons are involved in the regulation of growth hormone secretion from the pituitary by affecting periventricular SRIH neurons.

Animals↗
PubMed1990

Vasopressin-deficient paraventricular magnocellular neurons of homozygous Brattleboro rats synthesize neuropeptide Y.

Immunohistochemical study was carried out to determine whether neuropeptide Y (NPY), which was only found in certain experimental procedures in arginine vasopressin (AVP)-containing neurons of the magnocellular paraventricular nucleus, might also be synthesized in AVP-deficient homozygous Brattleboro (BB) rats. After an intraventricular colchicine administration, NPY was found in many AVP-deficient non-oxytocinergic magnocellular neurons of the paraventricular and supraoptic nuclei in BB rats, but not in suprachiasmatic nucleus neurons. The results suggest that the NPY synthesis is a phenotype of magnocellular non-oxytocinergic neurosecretory neurons and occurs independently from the synthesis of AVP.

Animals↗