Biomedical subjects

Y Tsuruo

Publications and source records attributed to Y Tsuruo.

61 records · Page 4Linked to original sources

PubMed1984

Ontogenetic appearance of somatostatin-containing nerve terminals in the median eminence of rats.

The development of immunoreactive (ir) somatostatin-containing nerve terminals in the rat median eminence (ME) has been examined electron-microscopically. Nerve fibers containing ir particles scattered throughout the axoplasm are first seen in the external layer of the ME on day 18.5 of gestation, and, on day 21.5 appear to terminate on the basement membrane of the perivascular space of the portal vessels. After birth, the fiber terminals contain several membrane-limited granules, which are labeled with ir PAP particles. Ultrathin, Epon-embedded sections of ME, treated by the protein A gold-labeling method for somatostatin, demonstrate positively labeled granules in the nerve fibers in the postnatal ME, but in the prenatal tissue, no specific gold-labeling is found. These findings show that, in the external layer of the ME, somatostatin storing occurs in the granules in the axonal terminals after birth.

Aging↗

PubMed1984

Immunohistochemical study on the development of CRF-containing neurons in the hypothalamus of the rat.

Appearance of immunoreactive corticotropin-releasing factor (CRF)-containing neurons was studied in developing hypothalamus of the rat by use of antisera against rat- and ovine CRF. These neurons were first recognized in the lateral and paraventricular nuclei on days 15.5 and 16.5 of gestation, respectively, when antiserum against rat CRF was employed. Antiserum against ovine CRF revealed the cells two days later exclusively in the latter nucleus. In both nuclei, the neurons increased in number with development. The neurons in the paraventricular nucleus appeared to project their immunoreactive processes to the median eminence via the periventricular and lateral pathways. In the median eminence, the immunoreaction with antiserum to rat CRF was first recognized in its anterior portion in the form of dots on day 16.5 of gestation but as beaded fibers in the external layer on day 17.5; these structures increased in amount with development in rostro-caudal direction. Although antiserum to ovine CRF was less potent in immunostainability than antiserum to rat CRF, it also revealed the beaded fibers in the median eminence on day 17.5 of gestation. Since evidence is available that the paraventricular nucleus is involved in corticotropin release, it is concluded that, in rats, the hypothalamic regulatory mechanism controlling the release of corticotropin initially appears on days 16.5-17.5 of gestation.

Animals↗

PubMed1983

Substance P-like immunoreactive neurons in the tuberoinfundibular area of rat hypothalamus. Light and electron microscopy.

Immunoreactive substance P (ir SP) neurons were examined with special reference to their links with other neurons and blood vessels in the tuberoinfundibular hypothalamic area of normal and colchicine-treated male rats. On intraventricular administration of colchicine, ir SP neuronal cell bodies appeared in both the arcuate nucleus and the ventral portion of the ventromedial nucleus. These ir fibers were seen in the nuclei of untreated animals closely surrounding ir methionine-enkephalin and ACTH cell bodies, suggesting the presence of synaptic junctions. Electron microscopic examination of the arcuate nucleus stained with anti-SP serum showed synapses of ir SP fiber terminals on unlabeled neuronal cell bodies and fibers, some of which might be methionine-enkephalin and ACTH neurons. The ir fiber terminals contained numerous small clear and/or cored vesicles and a few large cored vesicles. Fiber terminals with the same ultrastructural characteristics were seen protruding into the pericapillary space in the external and subependymal layers of the median eminence. The possible role of the SP neurons in the tuberoinfundibular area is discussed.

Animals↗

PubMed1983

Ontogenetic studies on the topographical heterogeneity of somatostatin-containing neurons in rat hypothalamus.

The ontogeny of the somatostatin-containing neuron system was investigated by light-microscopic immunohistochemistry. During development, immunoreactive somatostatin-containing neurons arise from three discrete regions of the neuroepithelium of the third ventricle and show a chronological difference. The neurons are first evident within the third ventricle floor on day 12.5 of gestation; they move thereafter to the arcuate nucleus. The second generation occurs in the dorsal region of the arcuate nucleus during days 17.5-19.5; these neurons migrate sequentially into the arcuate-ventromedial nuclear region. The third generation is recognized in the neuroepithelial cell layer of the rostral hypothalamus on day 17.5 of gestation; these cells move to the periventricular area. This latter generation is most prominent during days 3-6 after birth, and some of the cells are seen sporadically even up to day 20. The first two generations give rise to the somatostatin neuron system in the arcuate-ventromedial nuclear region, while the latter gives rise to that in the rostral periventricular region in the adult rat hypothalamus.

Animals↗

PubMed1983

Ontogenesis of hypothalamic immunoreactive ACTH cells in vivo and in vitro: role of Rathke's pouch.

The ontogenesis of immunoreactive (ir) ACTH cells and ir alpha-MSH cells in rat hypothalamus was studied in vivo and in vitro. Ir ACTH cells first appeared in the neuroepithelial cell layer lining the floor of the third ventricle on Day 13.5 of gestation, whereas ir alpha-MSH first appeared in the cytoplasm of several ir ACTH cells in the basal part of the arcuate nucleus of the hypothalamus on Day 19.5. When the medial-basal hypothalamus of 12.5-day embryos was cultured alone, a few ir ACTH cells were found after culture for 10 days, but not 3 days, and no ir alpha-MSH cells were observed in the cultures. When the hypothalamus was cultured with Rathke's pouch (intact or without the intermediate lobe anlage), ir ACTH cells appeared within 3 days. In these cultures on Days 6 and 10, long beaded fibers were seen projecting from cells in the neuronal tissue, and some cells showed immunolabeling for alpha-MSH. When the hypothalamus was cocultured with oral epithelium instead of Rathke's pouch, the appearance of neuronal ir ACTH cells was like that in cultures of hypothalamus alone. These in vitro findings suggest that stimulus from the anterior lobe anlage of the pituitary is necessary for normal development of ir ACTH/alpha-MSH cells in the hypothalamus.

Adrenocorticotropic Hormone↗

PubMedDate not supplied

Brain nitric oxides synthase in major pelvic ganglia of aged (LETO) and diabetic (OLETF) rats.

This study was conducted to evaluate the effects of aging and diabetes mellitus (DM) on brain nitric oxide synthase (bNOS) expression in major pelvic ganglia (MPG) of rats. Otsuka Long Evans Tokushima Fatty rats (12, 30, and 70 weeks old), which are genetic models with non-insulin-dependent DM (NIDDM), and age-matched nondiabetic Long Evans Tokushima Otsuka controls were used. The MPG of all rats in this study were subjected to cryo-sectioning and staining with bNOS polyclonal AB and rhodamine-conjugated rabbit IgG. Fluorescence intensities of the stained neurons were assessed in randomly selected fields per each specimen. Animals of both groups revealed significant decline in the staining intensity of their neurons with aging and the progress of DM, but diabetic rats showed more decline than controls. In conclusion, both aging and NIDDM could decrease bNOS expression in rat MPG. However, NIDDM has a more evident effect than aging on that expression. The decrease in bNOS may cause a disturbance in functions of the target pelvic structures of these ganglia under both conditions.

Aging↗

PubMedDate not supplied

Coexistence of TRH with other neuroactive substances in the rat central nervous system.

Colocalization of thyrotropin-releasing hormone-like immunoreactivity with other neuroactive substances was examined immunohistochemically in colchicine-treated rat brains using double-staining or elution-restaining methods. Thyrotropin-releasing hormone-like immunoreactivity was shown to be located in the same neurons as: 1. enkephalin-, gamma-amino butyric acid- and tyrosine hydroxylase-, but not somatostatin-like immunoreactivity in the glomerular layer of the olfactory bulb 2. oxytocin- and cholecystokinin-, but not vasopressin-like immunoreactivity in the supraoptic nucleus 3. cholecystokinin-like immunoreactivity in posterior pituitary 4. enkephalin-like immunoreactivity in the perifornical area of the hypothalamus and 5. neuropeptide Y- and neurotensin-like immunoreactivity in the periaqueductal central grey. These findings provide further examples of coexistence of thyrotropin-releasing hormone with classical neurotransmitters and/or peptides in the rat central nervous system.

Animals↗