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Y Tsuruo

Publications and source records attributed to Y Tsuruo.

At least 55 records · Page 3Linked to original sources
PubMed1988

Thyrotropin-releasing hormone (TRH)-immunoreactive neuron populations in the rat olfactory bulb.

Thyrotropin-releasing hormone (TRH)-like immunoreactivity was examined in the rat olfactory bulb by an immunohistochemical method using antiserum against the tripeptide TRH. TRH-immunoreactive neurons and neuronal processes were localized in both main and accessory olfactory bulb, including the glomerular layer, external plexiform layer, mitral cell body layer, internal plexiform layer and granule cell layer. However, no TRH-positive structures were observed in the olfactory nerve layer. The present study demonstrates that TRH is located in several neuronal populations in the olfactory bulb, and that this peptide thus may be involved in the processing of information in the olfactory system.

Animals↗
PubMed1988

Some blood vessels in the rat median eminence are surrounded by a dense plexus of vasoactive intestinal polypeptide/peptide histidine isoleucine (VIP/PHI) immunoreactive nerves.

Using immunohistochemistry at the light and electron microscopic level some blood vessels along the median eminence were shown to be surrounded by dense networks of vasoactive intestinal polypeptide/peptide histidine isoleucine (VIP/PHI)-positive fibers. VIP and PHI released from these fibers may contribute to the elevated levels of these two peptides measured in portal blood as compared to peripheral blood by radioimmunoassay. VIP and PHI may also be important in the control of blood flow through the median eminence.

Animals↗
PubMed1988

TRH-like immunoreactivity in endocrine cells and neurons in the gastro-intestinal tract of the rat and guinea pig.

By use of the indirect immunofluorescence technique, the cellular localization of thyrotropin-releasing hormone (TRH) was studied in the gastrointestinal tract of rats and guinea pigs of different ages. TRH-like immunoreactivity (LI) was observed in many pancreatic islet cells of young rats and guinea pigs but only in single cells of 6-month-old rats. In aged guinea pigs, a reduction in the number of TRH-positive cells was evident; however, numerous strongly fluorescent cells were still present. In the guinea pig, TRH-LI was in addition observed in gastrin cells in the stomach. TRH-positive nerve fibers occurred in the myenteric plexus of the oesophagus, stomach and intestine of the rat, and in the muscle layers of the guinea pig. These results suggest a functional role of TRH both as hormone and neuroactive compound in various portions and sites of the gastro-intestinal tract of the rat and guinea pig.

Animals↗
PubMed1988

Further analysis of presence of peptides in dopamine neurons. Cholecystokinin, peptide histidine-isoleucine/vasoactive intestinal polypeptide and substance P in rat supramammillary region and mesencephalon.

Double-labeling combined with elution-restaining immunofluorescence techniques were used to analyze the extent of coexistence among the peptides cholecystokinin (CCK), peptide histidine-isoleucine (PHI)/vasoactive intestinal polypeptide (VIP), substance P and the catecholamine-synthesizing enzyme tyrosine hydroxylase in neurons of the supramammillary region and mesencephalon of the rat. Approximately 50% of the PHI/VIP-containing perikarya and about 25% of the CCK-positive cell bodies in the supramammillary region exhibited coexistence of both peptides. Only a very minor portion of these double-labeled neurons were also found to contain immunostaining for tyrosine hydroxylase (indicative of dopamine in these cells). A low percentage of the neurons contained the enzyme plus either CCK- or PHI/VIP-like immunoreactivity. A low proportion of the tyrosine hydroxylase-positive neurons in this region contained substance P-like immunoreactivity and vice versa. In other areas, small numbers of neurons in periventricular and periaqueductal regions were found to be immunostained for CCK, PHI/VIP and tyrosine hydroxylase. Single examples of triple-labeled (CCK-PHI/VIP-TH) somata were infrequently observed in the ventral tegmental area. These data provide further evidence of peptide/peptide and peptide/monoamine coexistence in the central nervous system. The demonstration of CCK-PHI/VIP colocalization (possibly including a minor dopaminergic component) and of substance P and tyrosine hydroxylase coexistence within neurons of the supramammillary region, which has widespread projections to many areas of the forebrain, suggests that these neuropeptides may coexist in some of these pathways and perhaps be co-released in several different regions of the brain.

Animals↗
PubMed1988

DARPP-32, a dopamine- and cyclic AMP-regulated phosphoprotein in tanycytes of the mediobasal hypothalamus: distribution and relation to dopamine and luteinizing hormone-releasing hormone neurons and other glial elements.

The distribution of a dopamine- and cyclic adenosine-3':5'-monophosphate (cAMP)-regulated phosphoprotein with an apparent molecular weight of 32,000 (DARPP-32) was investigated in the rat diencephalon and monkey hypothalamus by use of immunohistochemical techniques. In addition to single cells located peri- and paraventricularly in hypothalamus and thalamus in the rat, and ependymal cells, DARPP-32-immunoreactivity was found to be present in a subpopulation of ependymal tanycytes. These DARPP-32-positive tanycytes lined the walls and floor of the third ventricle, sending processes towards the arcuate nucleus, surrounding blood vessels in this nucleus, and continuing towards the median eminence, where they abutted on portal vessels. A second group of DARPP-32-positive tanycytes with cell bodies within the median eminence was also observed. Simultaneous labeling with antiserum against tyrosine hydroxylase, a presumptive marker for tuberoinfundibular dopamine neurons, revealed a close relation to DARPP-32-containing tanycytes in several anatomical locations. Thus, in the periventricular area DARPP-32-positive tanycytes ensheathed tyrosine hydroxylase-positive processes. These processes, presumably representing dopaminergic dendrites, virtually penetrated between the ependymal cells to the ventricular space and thus perhaps established direct contact with the cerebrospinal fluid. Tyrosine hydroxylase-terminals were also observed in close association with DARPP-32-immunoreactive tanycytes in the rat median eminence. However, in view of the density of DARPP-32-positive processes in the external layer of the median eminence, the DARPP-32 processes may be related to a number of other types of nerve endings, including luteinizing hormone-releasing hormone, as shown in this study. The close association of DARPP-32-immunoreactive processes with tyrosine hydroxylase- and luteinizing hormone-releasing hormone-immunoreactive nerve endings in the rat was directly visualized at the ultrastructural level using triple-labeling immunocytochemistry. Both the ultrastructural analysis and immunohistochemistry at the light microscopic level, comparing the distribution of DARPP-32 and glial fibrillary acidic protein, indicated the presence of two types of glial processes in the median eminence. The electron microscopic studies also suggested the presence of both DARPP-32-positive and DARPP-32-negative glial processes in the external layer of the median eminence.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

Coexistence of peptides with classical neurotransmitters.

In the present article the fact is emphasized that neuropeptides often are located in the same neurons as classical transmitters such as acetylcholine, 5-hydroxy-tryptamine, catecholamines, gamma-aminobutyric acid (GABA) etc. This raises the possibility that neurons produce, store and release more than one messenger molecule. The exact functional role of such coexisting peptides is often difficult to evaluate, especially in the central nervous system. In the periphery some studies indicate apparently meaningful interactions of different types with the classical transmitter, but other types of actions including trophic effects have been observed. More recently it has been shown that some neurons contain more than one classical transmitter, e.g. 5-HT plus GABA, further underlining the view that transfer of information across synapses may be more complex than perhaps hitherto assumed.

Animals↗
PubMed1987

Intragranular colocalization of arginine vasopressin and methionine-enkephalin-octapeptide in CRF-axons in the rat median eminence.

Ultrastructural appearances of axonal terminals containing corticoliberin (CRF) were examined in the rat median eminence prepared by a freeze-drying procedure. Immunolabeling was performed by using 5-, 8-, or 15-nm gold-antibody complexes for CRF, arginine vasopressin (VP) and methionine-enkephalin-octapeptide (Enk-8), singly or in combination. In intact animals, the CRF-containing secretory granules were only slightly labeled with gold-anti-VP or -Enk-8. In adrenalectomized rats, granules within single axons appeared to be labeled with all the immunogold complexes. This intragranular colocalization of the three antigens was confirmed by using three neighboring sections of the same axon terminals which were stained separately with each one of the antibodies and visualized with the avidin-biotin-peroxidase complex method. The granules labeled for CRF had decreased 9 days after adrenalectomy but had increased again by day 21, while those labeled for VP steadily increased after adrenalectomy. However, this did not correspond with the appearances of cell bodies in the paraventricular nucleus; the cell bodies labeled for both CRF and VP steadily increased in number and in stainability. By contrast, Enk-8 immunoreactivity in the axonal terminals and cell bodies was not affected by adrenalectomy. These findings suggest that although the three peptides could be released simultaneously from the axonal terminals, VP may play some special role in the expression of CRF activity.

Adrenalectomy↗
PubMed1987

Thyrotropin releasing hormone (TRH)-immunoreactive cell groups in the rat central nervous system.

Using a paraformaldehyde-picric acid-glutaraldehyde-containing fixative and treatment of the tissue with sodium borohydride, numerous and widespread TRH-immunoreactive cell bodies were observed in the central nervous system of colchicine-treated rats, including the olfactory bulb, cortical and hippocampal areas, the caudate nucleus and other subcortical areas, many hypothalamic nuclei, the periaqueductal central gray, pontine nuclei, medulla oblongata and the dorsal horn of the spinal cord. Most of these cells could not be visualized with the same antiserum when conventional fixation methods based on formalin alone were used. The present findings suggest that TRH systems are considerably more extensive than hitherto assumed.

Animals↗
PubMed1987

Analysis of peptide histidine-isoleucine/vasoactive intestinal polypeptide-immunoreactive neurons in the central nervous system with special reference to their relation to corticotropin releasing factor- and enkephalin-like immunoreactivities in the paraventricular hypothalamic nucleus.

The distribution of peptide histidine-isoleucine (PHI) and vasoactive intestinal polypeptide (VIP), two peptides derived from the same precursor molecule, was analysed with immunohistochemistry in the central nervous system of the rat, and to a limited extent in some other species including sheep, monkey and man. Special attention was focused on possible cross-reactivity between PHI antisera and corticotropin releasing factor in parvocellular neurons in the hypothalamic paraventricular nucleus projecting to the external layer of the median eminence. (1) Characterization of the PHI and VIP antisera revealed that they recognized different sequences of the peptide molecules. One of the PHI antisera (PHI-N), although mainly N-terminally directed, also probably contained an antibody population directed against the C-terminal amino acid in PHI which is an amidated isoleucine. Rat and human corticotropin releasing factor but not ovine also have an amidated isoleucine in C-terminal position. (2) PHI- and VIP-like immunoreactivity were found with parallel and overlapping distribution in all areas investigated in the rat central nervous system. In many cases coexistence of the two immunoreactivities could be directly demonstrated. PHI neurons were found in some areas so far not know to contain PHI/VIP neurons, including the dorsal septum, the septofimbrial nucleus, the stria terminalis and lamina V of the spinal cord. (3) Using an antiserum directed against the amino acid sequence 111-122 of the VIP/PHI precursor, immunoreactive cell bodies were seen in some areas containing VIP and PHI neurons. PHI- and VIP-like immunoreactivity were expressed in parallel in increasing amounts in the superficial laminae of the dorsal horn after transection of the sciatic nerve [G. P. McGregor et al. (1984) Neuroscience 13, 207-216; S. A. S. Shehab and M. E. Atkinson (1984) J. Anat. 139, 725; S. A. S. Shehab and M. E. Atkinson (1986) Expl Brain Res. 62, 422-430]. (5) The PHI-N antiserum stains large numbers of immunoreactive cells in the parvocellular part of the paraventricular nucleus and these cells are mostly identical with corticotropin releasing factor-positive neurons. Absorption experiments suggested that this PHI-N-like immunoreactivity to a large extent represented cross-reactivity with rat CRF and that earlier demonstration of many PHI-positive neurons in the paraventricular nucleus probably represents an artefact as proposed by F. Berkenbosch et al. (Neuroendocrinology 44, 338-346). However, some cells did, in fact, contain VIP- as well as PHI-like immunoreactivity as was shown with antisera not cross-reacting with corticotropin releasing factor.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

Immunohistochemical studies on the roles of substance P in the rat hypothalamus: possible implication in the hypothalamic-hypophysial-gonadal axis.

The hypothalamic neurons containing substance P (SP) were examined immunohistochemically in rats with a normal estrous cycle or persistent estrus (PE), in pregnancy and in lactating state. In PE animals, the neurons increased in number 1 week after ovariectomy, but then decreased and disappeared. During pregnancy, there were many SP neurons at an early stage but later they gradually decreased in number and disappeared. Consequently, during lactation no SP neurons were evident. The external layer of the median eminence (ME) contained many immunolabeled nerve terminals. In the ME prepared by a freeze-drying technique and immunostained with gold-labeled IgG by the postembedding procedure, the immunolabeled terminals were seen to contain large cored vesicles (50-100 nm) labeled with gold and unlabeled small clear vesicles (30-50 nm). In normal cycling rats, the terminals contained large cored vesicles in diestrus, small clear vesicles in estrus, and both in proestrus. In PE rats, the terminals contained only small clear vesicles, but the cored vesicles appeared after ovariectomy. In the early stage of pregnancy, the terminals contained only small clear vesicles, but the large cored vesicles appeared in late pregnancy and during lactation. These findings present further evidence that the hypothalamic SP neurons are involved in the hypothalamic-hypophysial-gonadal axis in rats.

Animals↗
PubMed1987

Differential immunolabeling for electron microscopy of diverse peptidergic neurons.

We describe a simple and reliable method for differential immunolabeling of pre- and post-synaptic signal peptides at the ultrastructural level. Hypothalamic tissues of rats, including the suprachiasmatic nucleus, were cut on a Vibratome. Visualization of the immunolabeling of somatostatin (SRIH) and vasoactive intestinal polypeptide (VIP) was performed with avidin-biotin-peroxidase-diaminobenzidine (DAB). The end product of the DAB to VIP was further silver-intensified in a physical processing using silver nitrate, and the silver grains were finally substituted for gold. DAB-labeled SRIH fibers synapse on gold-labeled VIP perikarya and dendrites in the suprachiasmatic nucleus.

Animals↗
PubMed1986

Immunocytochemical evidence for synaptic regulation of paraventricular vasopressin-containing neurons by substance P.

Employing a combination of pre-embedding peroxidase-antiperoxidase-labeling for substance P (SP) and postembedding immunogold labeling with protein A-colloidal gold-anti-arginine vasopressin (AVP) complex, we demonstrated immunoreactive SP containing nerve fibers, which terminate synaptically on the perikarya, contained gold-labeled secretory granules in the magnocellular paraventricular nucleus of rats. The perikarya were also synapsed with unlabeled nerve fibers. It is concluded that SP plays a role as an axosomatic neurotransmitter in diverse synaptic controls of vasopressinergic neurons.

Animals↗
PubMed1986

Immunoelectron microscopic observations of hypothalamic TRH-containing neurons in rats.

Immunoreactive TRH-containing neurons and their synaptic associations were studied electron microscopically in the paraventricular nucleus (PVN) and dorsomedial nucleus (DMH) of the rat hypothalamus. In propylthiouracil (PTU)-treated rats, the immunoreactive cell bodies in the PVN appeared to be activated, showing a hypertrophic perikaryon, well developed Golgi bodies and numerous secretory granules. No such alterations were evident in the TRH neurons in the DMH. These findings suggest that the PVN-TRH neurons are involved in the hypothalamic-hypophysial-thyroid axis. Further, it was shown that unlabeled nerve terminals containing small and large clear vesicles make synaptic contacts with the TRH perikarya in the PVN. Thus it is likely that PVN-TRH neurons are regulated both by thyroid hormones and by other neuronal signals. In the DMH, unlabeled nerve terminals containing small and large clear vesicles, and immunoreactive terminals form synapses with TRH neurons. Thus the DMH-TRH neurons may be under dual neuronal control. It was further noted that in the DMH and PVN, TRH nerve terminals make synaptic contacts with other unlabeled neurons. It is evident that TRH acts as a neurotransmitter or neuromodulator, although the origin of TRH terminals should be elucidated.

Animals↗
PubMed1985

Hypothalamic thyrotropin-releasing hormone (TRH)-containing neurons involved in the hypothalamic-hypophysial-thyroid axis. Light microscopic immunohistochemistry.

The localization of neurons containing immunoreactive thyrotropin-releasing hormone (TRH) was examined in the hypothalamus of intact, propylthiouracil (PTU)-treated, and colchicine-treated adult rats. In intact animals, immunoreactive TRH neurons were occasionally found in the paraventricular and dorsomedial nuclei, and in the anterior and lateral hypothalamic areas. In PTU-treated animals, the cellular appearance of the hypothalamus with the exception of the paraventricular nucleus was almost similar to that of intact animals. In the paraventricular nucleus, only the cells localized in the periventricular and medial parvocellular subdivisions significantly increased in number and became hypertrophic in comparison with intact animals. The distribution of immunoreactive fibers in the hypothalamus was almost equal among the 3 animal groups with the exception of that in the median eminence, in which the fibers were most densely concentrated in intact animals, and most sparse in PTU-treated rats. The fibers projecting into the median eminence were distinguished into the periventricular and lateral pathways, which are derived from the neurons in the periventricular and medial parvocellular subdivisions of the paraventricular nucleus, respectively. Thus, among immunoreactive TRH neurons in the hypothalamus, only those in the periventricular and medial parvocellular subdivisions of the paraventricular nucleus may be involved in the hypothalamic-hypophysial-thyroid axis.

Animals↗
PubMed1985

CRF-containing neurons of the rat hypothalamus.

The immunoreactive CRF-neurons of the rat hypothalamus have been examined immunohistochemically employing anti-rat CRF serum. These neurons are confined to the paraventricular nucleus, dorsomedial-lateral hypothalamic area, and suprachiasmatic nucleus, and are, respectively, also immunoreactive to anti-Met-enk, -alpha-MSH, and -VIP sera. Intraventricular administration of colchicine (50 micrograms/5 microliters/rat) induces a dramatic enhancement of the immunostainability of the cell somata, and also accelerates the development of immunoreactivity of other stored peptides, especially in the paraventricular nucleus. The CRF-neurons respond to adrenalectomy by showing increased immunoreactivity and an increase in the number of cell bodies; in the dorsomedial-lateral area and suprachiasmatic nucleus, there is also an enhanced immunoreactivity for alpha-MSH and VIP, respectively. CRF-cells in the paraventricular nucleus become markedly hypertrophied, but do not show any enhanced immunoreactivity for Met-enk. Since the axons of the paraventricular neurons run to the median eminence, it is probable that they are involved with the endocrine control of hypophysial ACTH release. It is concluded that the CRF-containing neurons in rat hypothalamus consist of three types which are functionally and morphologically different.

Adrenalectomy↗
PubMed1984

Hypothalamic substance P-containing neurons. Sex-dependent topographical differences and ultrastructural transformations associated with stages of the estrous cycle.

Immunoreactive substance P (ir SP)-containing neurons were examined in rat hypothalamus. In untreated males, few if any ir perikarya were found in the arcuate nucleus, but after intraventricular colchicine administration, many appeared not only in the arcuate nucleus but also in the premammillary region, posterior hypothalamic, ventromedial, dorsomedial, subthalamic and paraventricular nuclei, and zona incerta. This was also the case in females treated with colchicine on the second day of diestrus. In untreated females, perikarya were seen only in the arcuate nucleus, varying in number and ultrastructure during the estrous cycle and being maximal in number in proestrus and estrus. The perikarya possessed well-developed Golgi bodies and lamellar bodies composed of many closely apposed cisternae of endoplasmic reticulum in proestrus, and showed stacks of two or three cisternae of endoplasmic reticulum as well as lysosomes in estrus. In diestrus, the perikarya had only a few granulated vesicles and fragmental cisternae of endoplasmic reticulum. In the perikarya of colchicine-treated males, many granulated vesicles and lysosomal bodies were noted. These findings suggest that, among the widely distributed SP neurons in the hypothalamus, some in the arcuate nucleus are involved in the hypothalamic-hypophysial-gonadal axis.

Animals↗
PubMed1984

Morphological evidence for synaptic junctions between substance P-containing neurons in the arcuate nucleus of the rat.

The presence of synaptic junctions between substance P-containing neurons (SP neurons) was shown in the hypothalamic arcuate nucleus of rats by pre-embedding electron microscopic immunohistochemistry. The immunoreactive perikarya were synapsed by immunoreactive fiber terminals as well as immunonegative fiber terminals. The functional implication of the synapses between SP neurons is discussed in relation to autoregulatory mechanisms of the neurons.

Adrenocorticotropic Hormone↗