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S Kito

Publications and source records attributed to S Kito.

At least 73 records · Page 4Linked to original sources
PubMed1989

Somatostatin increases intracellular Ca2+ concentration in cultured rat hippocampal neurons.

Changes of intracellular Ca2+ concentration [( Ca2+]i) in response to somatostatin were measured in cultured rat hippocampal neurons on a single cell basis by fura-2 fluorometry. Somatostatin increased [Ca2+]i dose-dependently and this effect was completely blocked in either Ca2+-depleted medium or LaCl3-containing medium. In addition, omega-conotoxin GVIA completely inhibited the effect of somatostatin. Our results indicate that somatostatin receptors couple with N-type voltage-sensitive Ca2+ channels in cultured rat hippocampal neurons.

Animals↗
PubMed1989

The coexistence of substance P- and glutamic acid decarboxylase-like immunoreactivity in entopeduncular neurons of the rat.

The coexistence of substance P- and glutamic acid decarboxylase-like immunoreactivity in cell bodies was investigated in the entopeduncular neurons of the rat by the double-immunofluorescence method using species-specific antibodies. Over half of the substance P-like immunoreactive cells were GABAergic. Double-labeled neurons were generally seen in the rostral to the middle region of the entopeduncular nucleus. Since the rostral portion of the entopeduncular nucleus mainly projects to the lateral habenular nucleus, it is suggested that double-labeled neurons in the entopeduncular nucleus largely project to the lateral habenular nucleus which is involved in the limbic system.

Animals↗
PubMed1989

Light and electron microscopic studies of calcitonin gene-related peptide-like immunoreactive terminals in the central nucleus of the amygdala and the bed nucleus of the stria terminalis of the rat.

Light and electron microscopic analysis of calcitonin gene-related peptide (CGRP)-like immunoreactive (LI) terminals in the bed nucleus of the stria terminalis (BST) and the central nucleus of the amygdala (Ce) was carried out using the peroxidase-antiperoxidase method. CGRP-LI fibers were densely distributed in the dorsal subdivision of the lateral BST (BSTL) and the lateral and lateral capsular subdivisions of the Ce, where the CGRP-LI terminals formed symmetrical and asymmetrical axo-dendritic, and symmetrical axosomatic synapses. One of the most characteristic features of the CGRP-LI terminals was the presence of large, long boutons, each of which surrounded a cell soma and made many synaptic contacts. These findings suggest that CGRP exerts a significant influence on neurons in the BSTL and Ce.

Amygdala↗
PubMed1989

A light and electron microscopic study of calcitonin gene-related peptide in the rat caudate putamen.

Calcitonin gene-related peptide (CGRP)-like immunoreactive (CGRP-IR) structures have been studied in the rat caudate putamen using avidin-biotin peroxidase immunohistochemistry. Immunoreactivity was found in the axons of this nucleus but not in the perikarya. CGRP-IR fibers were most densely concentrated along the ventral border and in the caudal portion of the rat caudate putamen. CGRP-IR fibers were sparsely distributed throughout the rest of this nucleus. Almost all immunoreactive boutons which contained small clear vesicles had formed asymmetrical synapses. Postsynaptic targets included dendritic spines and shafts. Asymmetrical synapses in the caudate putamen are supposed to be extrinsic in origin. These observations, together with the results of other investigations, suggest that CGRP-IR boutons form synapses with spiny striatal neurons, which, most likely, are medium-sized spiny projecting neurons. Moreover, evidence indicates that these boutons are of extrinsic origin.

Animals↗
PubMed1989

Genetic and clinical studies of Japanese patients with familial amyloid polyneuropathy.

We examined the DNA analysis of familial amyloid polyneuropathy (FAP) patients and their families from Nagano and Hiroshima prefectures in Japan using recombinant DNA techniques and compared the results with the clinical features. This study indicated that the valine-methionine change prealbumin gene was closely related to the clinical features of type 1 FAP. The DNA analysis was valuable for the definite diagnosis of type 1 FAP even in sporadic and asymptomatic cases. FAP patients from Iiyama city and Ogawa village area in the Nagano prefecture had the same mutation despite differences in clinical features. The onset of the sporadic FAP cases was later than that of the FAP patients who had family histories.

Adult↗
PubMed1989

Quantitative autoradiographic localization of the M1 and M2 subtypes of muscarinic acetylcholine receptors in the monkey brain.

The distribution of muscarinic acetylcholine receptors (mAChR) was investigated in the monkey brain by means of quantitative in vitro autoradiography. 3H-QNB, 3H-pirenzepine (PZ) and 3H-AF-DX 116 were used for labelling total mAChR, M1 and M2 receptors, respectively. 3H-PZ and 3H-AF-DX 116 showed specificity to each receptor subtype in the monkey brain. On sections containing the putamen and globus pallidus, the sum of Bmax values of 3H-PZ and 3H-AF-DX 116 binding sites was almost close to that of 3H-QNB binding sites. Autoradiographic distributions of muscarinic subtype receptors in the monkey brain were similar to those reported in the rat brain; that is, M1 receptors were dominant in most areas of the telencephalon, while M2 receptors were richly distributed in the brainstem and cerebellum. However, some nuclei of the brainstem such as the central gray matter, superior colliculus, substantia nigra, nucleus of the oculomotor nerve, pontine nucleus and inferior olivary nucleus, had relatively high ratios of M1 receptors in the monkey brain. In addition, the cortical lamminar distribution of M2 receptors noticed in the rat was not observed in the monkey brain. Knowledge about the localizations of M1 and M2 receptors in various brain regions in the monkey brain will increase our understanding of the functions of the brain cholinergic system in the primate.

Animals↗
PubMed1989

Treatment by pacemaker in familial amyloid polyneuropathy.

Amyloid deposits often involve the heart and cause disturbances in conduction and impulse formation in patients with familial amyloid polyneuropathy (FAP). Seven patients with FAP required pacemaker treatment during eight years. The most frequent bradyarrhythmias requiring pacing were sinus node dysfunction with junctional failure. Our seven patients had attacks and symptoms of bradyarrhythmias. A pacemaker relieved symptoms of bradycardias with recurrence of dislocation of electrode, exit block, and relatively high threshold. However, pacing did not improve the ultimate prognosis of FAP, because of progressive inanition of FAP. In our series, pacing should have been started earlier before advanced stage according to the ECG findings as in other diseases with bradycardias.

Adult↗
PubMed1989

[A case of Kennedy-Alter-Sung syndrome associated with external ophthalmoplegia--therapeutic efficacy of fluoxymesterone].

We reported a case with Kennedy-Alter-Sung syndrome (KAS) associated with bilateral external ophthalmoplegia. The patient had movement disturbance of bilateral infra-oblique muscles. The doll's eye phenomenon was not noted. It was suggested that the external ophthalmoplegia was due to the involvement of the oculomotor nucleus that innervated infra-oblique muscle. The serum levels of testosterone and gonadotropin were high, suggesting that the feminization of KAS patients was caused by androgen insensitivity. The feminization of KAS patients is similar to the incomplete form of testicular feminization syndrome except that they do not have feminization of genitals. Therefore, we proposed that abnormalities of androgen receptors might play a role in the pathogenesis of KAS. Fluoxymesterone therapy significantly improved the muscle weakness of the extremities of the patient, even though the therapeutic efficacy was shown temporarily. The therapeutic efficacy of fluoxymesterone for muscle weakness supports our hypothesis.

Androgen-Insensitivity Syndrome↗
PubMed1989

Clinical features and diagnosis by recombinant DNA techniques of familial amyloid polyneuropathy in Japan.

Diagnosis of familial amyloid polyneuropathy (FAP) was investigated by recombinant DNA techniques using Southern blot hybridization in 49 constituents of FAP pedigrees originated from Nagano and Hiroshima Prefectures in Japan. The results were correlated with clinical features of the patients. Twenty-nine patients originated from Ogawa Village in Nagano Prefecture of the central part of Japan had typical clinical features of Andrade type FAP including polyneuropathy with autonomic disorders. The variant prealbumin gene with a substitution of methionine (Met) for valine (Val) at position 30 was detected in their DNA analysis (positive DNA diagnosis). In 5 cases from Nagano and Hiroshima Prefectures who had clinical features of Andrade type FAP but no family history, DNA diagnosis was positive. In another 5 members of FAP pedigrees originated from Ogawa Village without clinical features of FAP, DNA diagnosis was positive. Two cases originated from Iiyama City in Nagano, who had central nervous system disorders resembling spinocerebellar degeneration with spastic paraplegia besides clinical features of Andrade type FAP, had the Val-Met interchange variant prealbumin gene. In a case from the same Iiyama family who had only the central nervous system disorders without clinical features of FAP, DNA diagnosis was negative. These findings indicate that the presence of the variant prealbumin gene closely linked to the clinical manifestations of Andrade type FAP. The diagnostic DNA analysis was considered to be useful for the diagnosis of Andrade type FAP for sporadic cases as well as so far nonsymptomatic gene carriers. In conclusion, FAP patients originated from Iiyama City and Ogawa village were considered to have the same mutation despite the variances in clinical features.

Adult↗
PubMed1988

Ontogeny of calcitonin gene-related peptide-immunoreactive structures in the rat forebrain and diencephalon.

Ontogeny of the calcitonin gene-related peptide (CGRP)-containing structures was investigated in the forebrain and diencephalon of the rat by means of indirect immunofluorescence. CGRP-like immunoreactive (CGRP-IR) fibers first appeared at gestational day 18 (E18) in the primordia of the bed nucleus of the stria terminalis, central amygdaloid nucleus and posterolateral portion of the lateral hypothalamic nucleus. CGRP-IR fibers gradually increased in immunoreactivity and in number in these nuclei toward birth. A pronounced increase of CGRP-like immunoreactive fibers was found after birth in these nuclei and made very dense plexuses of fibers in adult animals. A few CGRP-IR fibers first appeared at the perinatal stage in the lateral septum, the most caudal portion of the caudate-putamen, and ventromedial and ventroposterior thalamic nuclei. Then the immunoreactive fibers increased and dense plexuses were present in these brain areas of the adult. A small number of immunoreactive fibers appeared at postnatal day 4-7 (P4-7) in the caudal insular cortex and ventromedial hypothalamic nucleus. A significant number of fibers was present in these areas of the adult. On the other hand, CGRP-like immunoreactivity in cell bodies was first detected with faint immunofluorescence at P4 in the anteromedial parts of the lateral hypothalamic area and ventromedial and ventroposterior thalamic nuclei. Thereafter CGRP-IR cells increased in immunoreactivity, and a significant number of cells was noted in these nuclei of the adult. In addition, CGRP-IR cells are identified in the medial amygdaloid nucleus, and medial preoptic area at P14. In conclusion, in the forebrain and diencephalon (1) CGRP-like immunoreactivity appears in fibers earlier than in cell bodies, suggesting that at least some of immunoreactive fibers originate from the lower brainstem, and (2) high density of CGRP-IR structures present in the brain at embryonic and early postnatal stages may indicate that CGRP could be an important factor involved in the developmental organization of the central nervous system.

Aging↗
PubMed1988

Neuropeptide Y-immunoreactive neurons receive synaptic inputs from dopaminergic axon terminals in the rat neostriatum.

Double immunocytochemistry using peroxidase-antiperoxidase and protein A-gold was performed to determine whether neuropeptide Y (NPY) immunoreactive neurons receive synaptic inputs from catecholaminergic axon terminals in the rat neostriatum. Tyrosine hydroxylase-immunoreactive axons were found to be in synaptic contact with the somas and proximal dendrites of NPY-immunoreactive neostriatal neurons. These latter neurons were medium-sized and had indented nuclei, and thus were thought to be medium aspiny interneurons. Thus nigrostriatal dopaminergic neurons may monosynaptically influence striatal NPY neurons.

Animals↗
PubMed1988

A study of the central cavity in the bovine corpus luteum.

Seven hundred and six bovine corpora lutea in various luteal stages were examined morphologically and endocrinologically to discover whether there is a relationship between the presence of a central cavity in the corpus luteum and infertility in cows. A central cavity was found in 42.1 per cent (80/190) of developing corpora lutea, 33.7 per cent (126/374) of fully developed corpora lutea, 11.1 per cent (7/63) of corpora lutea in regression and in 5.1 per cent (4/79) of corpora lutea in pregnancy. There was no significant difference between the rates of appearance of midcycle follicles in corpora lutea either with or without a central cavity. The proportion of luteal cell type 1 was higher in fully developed corpora lutea with a central cavity than without, but the reverse was found with luteal cell type 2. In fully developed corpora lutea the concentration of progesterone in the luteal tissue was significantly higher in corpora lutea with a central cavity. These results suggest that there are some differences in luteal function between corpora lutea with and without a central cavity, but that the presence of a central cavity in a corpus luteum cannot be described as a pathological condition.

Animals↗
PubMed1988

Ontogeny of the calcitonin gene-related peptide in the nervous system of rat brain stem: an immunohistochemical analysis.

The ontogeny of the calcitonin gene-related peptide in the neuron system of the rat brain stem was investigated by means of the indirect immunofluorescence technique. Calcitonin gene-related peptide-like immunoreactivity was first detected in the fibers of the nucleus of spinal tract trigeminal nerve on gestational day 18, and thereafter appeared gradually in various brain stem areas such as in the fibers of the solitary tract, gracile nucleus, cuneate nucleus, inferior colliculus, superior colliculus, medial geniculate nucleus and in the neurons of the hypoglossal nucleus, facial nucleus, superior olive, parabrachial area, superior colliculus and peripeduncular nucleus. In colchicine-untreated animals, the immunoreactive fibers increased in number and reached adult level by postnatal day 14, whereas the number of cells reached a maximum between postnatal days 2 and 6 and then decreased in number and immunoreactivity or disappeared, except in some areas such as the superior olive and peripeduncular nucleus, which showed the same immunoreactivity as for adult animals. With colchicine treatment, calcitonin gene-related peptide-like immunoreactive cells were found in more areas of the brain stem such as the abducens nucleus, parabigeminal nucleus, principal oculomotor nucleus, trochlear nucleus and central gray, along with the nuclei which had shown calcitonin gene-related peptide immunoreactivity in the untreated animals. However, the neurons in the inferior olive showed a different ontogenetical pattern of calcitonin gene-related peptide of immunoreactivity. Immunoreactivity disappeared completely by postnatal day 21 in both colchicine-untreated and -treated animals.

Aging↗
PubMed1988

Alterations of the central noradrenergic system in MPTP-induced monkey parkinsonism.

Alterations of the coeruleo-cortical adrenergic system in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced monkey parkinsonism were examined through neuropathological observation and radioreceptor assay. Neuronal degeneration was found not only in the substantia nigra but also in the locus coeruleus of all the MPTP-treated monkeys. From radioreceptor assay, decreases of alpha 1 and alpha 2 receptors in the parietal and temporal cortices were observed in parkinsonian monkeys. In addition, beta receptors increased in the temporal cortex. These changes in monkey parkinsonism are very similar to those in human Parkinson's disease.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1988

Effects of 3-methyl-1-(5-oxohexyl)-7-propylxanthine on the in vivo release of monoamines studied by intracerebral dialysis.

The effect of a xanthine derivative, 3-methyl-1-(5-oxohexyl)-7-propylxanthine (HWA 285, 10 mg/kg i.p.), on the release of endogenous monoamines and their metabolites from the rat striatum and hippocampus are examined in vivo by intracerebral dialysis technique. Using this method, which is based on the dialysis principle, a small-calibered (0.5 mm) dialysis tube is inserted into the striatum or hippocampus transversally and is perfused with Ringer solution. The amounts of dopamine, 3,4-dihydroxyphenylacetic acid, homovanillic acid, 5-hydroxytryptamine and 5-hydroxyindoleacetic acid in the perfusates are measured by high performance liquid chromatography system with electrochemical detection. HWA 285 (10 mg/kg) decreased monoamine levels in hippocampal perfusates after its i.p. administration. However, there were no consistent changes in monoamine release in striatal perfusates after the drug administration. These findings suggest that HWA 285 exerts an inhibitory influence on hippocampal dopaminergic and serotonergic systems.

Animals↗
PubMed1987

Coexistence of substance P- and enkephalin-like peptides in single neurons of the rat hypothalamus.

The distribution of substance P- and enkephalin-like immunoreactivity in single cells were examined by the double immunofluorescence method. Substance P- and leucine-enkephalin-like compounds coexisted within individual neurons of some hypothalamic areas such as the medial preoptic area, anterior hypothalamic area, perifornical area, lateral hypothalamic area, premammillary nuclei and posterior hypothalamic nucleus, although they did not coexist in the majority of immunoreactive cells.

Animals↗