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Biomedical subjects

H Kiyama

Publications and source records attributed to H Kiyama.

At least 127 records · Page 7Linked to original sources
PubMed1994

Coexpression of GABAA receptor gamma 1 and gamma 2 subunits in the rat trigeminal ganglion.

We examined the expression of gamma-aminobutyric acid (GABA)A receptor gamma 1 and gamma 2 subunit mRNAs in the rat trigeminal ganglion using in situ hybridization histochemistry. Most ganglion cells expressed both gamma 1 and gamma 2 mRNAs simultaneously. These findings are a marked contrast to the findings in the central nervous system where areas expressing both subunits are rare. In addition, we demonstrated using immunohistochemistry that the gamma 1 subunit is also expressed at the protein level in trigeminal ganglion neurons and fibers in the trigeminal spinal nucleus.

Animals↗
PubMed1994

GAP-43 (B50/F1) gene regulation by axonal injury of the hypoglossal nerve in the adult rat.

The expression of mRNA encoding the growth associated protein, GAP-43, was investigated in rat hypoglossal motor neurons when the hypoglossal nerve was either resected or crushed unilaterally. For the detection of GAP-43 mRNA, a histochemical in situ hybridization method. using an alkaline phosphatase labeled probe, was used. The temporal profiles of GAP-43 mRNA expression were not identical following the two types of injuries. Increased expression in the hypoglossal nucleus contralateral to the injured nerve was observed from 1 day to 4-6 weeks after nerve crush, but lasted up to 7-8 weeks after resection. The magnitude and duration of increased GAP-43 mRNA expression were significantly greater following resection than crush injury. Local treatment with vinblastine, which is known to disturb the fast axonal flow by depolymerizing tubulin, also induced GAP-43 mRNA expression. The patterns of gene regulation following these nerve injuries may be due to the extent of nerve damage, to tubulin disturbance, or to some other factors derived from outside the nerve.

Animals↗
PubMed1994

Marginal topography of neurons expressing the substance P receptor in the rat suprachiasmatic nucleus.

Neurons expressing the substance P (SP) receptor (NK1 receptor) in the suprachiasmatic nucleus of the hypothalamus (SCN) have been topographically identified using radioactive in situ hybridization histochemistry. In the anterior hypothalamic area, clustered labeled neurons of small size and exhibiting low levels of gene expression are observed exclusively at the dorsolateral margin of the SCN, straddling cytoarchitectural boundaries of the nucleus. The marginal topography of neurons putative target of a SP-containing retinal input to the ventral SCN indicates that their dendrites bearing the receptor extend towards the retinorecipient part of the nucleus, where they can be modulated by overlapping inputs from the intergeniculate leaflet and the raphe. Eventual interactions between glutamatergic and putative tachykininergic retinal pathways for a coherent photic control of circadian rhythms may therefore occur mainly via intrinsic neuronal connections between their distinct target populations. In addition, since glutamate and SP induce electrophysiological responses in ventrolateral neurons with no interactive effect, neurons integrating both chemical signals, subsequently to their modulation by several influences, may be not located within the ventrolateral SCN. Alternatively but not exclusively, marginal neurons could be a target of SP-containing neurons within the SCN or nearby the nucleus, or from ascending projections from the raphé where serotonin and SP colocalize. The marginal topography of neurons expressing the SP receptor supports the view of the involvement of neurons located in the vicinity of the nucleus in the regulation of circadian rhythms.

Animals↗
PubMed1994

Differential regulation of phospholipase C isozymes in the rat facial nucleus following axotomy.

The expression of phospholipase C isozymes and phosphatidylinositol 4-kinase in the rat facial nucleus was studied using in situ hybridization at various times after unilateral crushing and resectioning the facial nerve. The level of phospholipase C alpha messenger RNA increased from three days to one week after the operation. On the other hand, an apparent reduction in the level of phospholipase C beta 1 occurred from three days to one week after resection. After either crushing or resection, phospholipase C gamma 1 messenger RNA levels were not noticeably changed. As phosphatidylinositol 4-kinase is the rate-limiting enzyme for the production of phosphatidylinositol 4,5-bisphosphate, which is the preferred substrate for phospholipase C, we investigated the expression of phosphatidylinositol 4-kinase messenger RNA. The level of phosphatidylinositol 4-kinase messenger RNA was decreased one day after axonal injury. Among phospholipase C isozymes, phospholipase C alpha is up-regulated. As the structure of phospholipase C alpha is different from other isozymes, phospholipase C alpha is supposed to have a different function. The present unique up-regulation of phospholipase C alpha may suggest a novel function in nerve regeneration. Phospholipase C beta 1 is down-regulated, as is phosphatidylinositol 4-kinase. This suggests that the signal transmission system using a G-linked receptor is broken down after nerve injury. On the other hand, phospholipase C gamma 1, which is related to the receptor tyrosine kinase, does not demonstrate any transcriptional regulation after nerve injury.

1-Phosphatidylinositol 4-Kinase↗
PubMed1994

Gene regulation of cyclic AMP-dependent protein kinase subunits (C alpha, beta; RI alpha, beta and RII alpha, beta) in rat facial motoneurons after nerve transection.

In this study we investigated the changes in gene expressions of catalytic (C alpha, beta) and regulatory (RI alpha, beta and RII alpha, beta) subunits of cAMP-dependent protein kinase (PKA) in axotomized facial motoneurons of the rat. Nerve transection induced changes in the expression of C subunit messenger RNAs and RII subunit messenger RNAs. Control facial motoneurons had a high expression of both C alpha and C beta subunit messenger RNAs, but their expression declined after axotomy. The decrease was most pronounced at postoperative week 2 and returned to basal level within postoperative week 4. In contrast, the expression of both RII alpha and beta subunit messenger RNAs, which were low in control facial motoneurons, was increased after axotomy. Enhancement of RII subunits messenger RNAs was apparent during postoperative weeks 1 and 3, and then returned to the basal level. RI alpha, beta subunits messenger RNAs were strongly expressed in normal facial motoneurons, but were not clearly influenced by axotomy. These results indicate an attenuation of total PKA activity in axotomized facial motoneurons. Furthermore, such gene regulation may imply a change of the targets for PKA in facial motoneurons during the process of neurite regeneration.

Animals↗
PubMed1994

Up-regulation of GAP-43 (B50/F1) gene expression in vestibular efferent neurons following labyrinthectomy in the rat: in situ hybridization using an alkaline phosphatase-labeled probe.

Growth-associated protein (GAP)-43 plays a significant role in nerve regeneration and synaptic remodeling. We examined the profiles of GAP-43 mRNA expression in vestibular efferent neurons after labyrinthectomy in adult rats, and clearly demonstrated that labyrinthectomy increased GAP-43 expression in these neurons. This finding suggests the ability of vestibular efferent nerves to regenerate after nerve injury.

Alkaline Phosphatase↗
PubMed1994

Regulation of Src family kinases in the developing rat brain: correlation with their regulator kinase, Csk.

We have so far suggested that the functions of Src family protein-tyrosine kinases are under the control of their regulator kinase, Csk. To evaluate the role of Csk-mediated regulation in neural tissues, we examined the correlation between the activities of Src family kinases and the expression level of Csk during development of the rat brain. Csk was expressed at high levels in the developing embryonic brain and then rapidly decreased as the brain matured. Consistent with the decrease in the Csk level, the kinase activity of a member of the Src family, Fyn, was greatly enhanced, but that of Src was not correlated inversely with the level of Csk expression. Src exhibited elevated activity in the developing brain, in which a neuronal form of Src (N-Src) is expressed as the dominant form of Src. Although N-Src was readily down-regulated by Csk when coexpressed in yeast, it showed much higher specific activity than c-Src, even in the repressed form. These findings suggest that neural tissues acquire high activities of Src family kinases, which might be important for differentiation and development of the nervous system, through induction of the active form of Src (N-Src) and down-regulation of their suppresser, Csk.

Amino Acid Sequence↗
PubMed1994

Growth factors and extracellular signal-regulated kinases (mitogen-activated protein kinase) in the rat pineal gland.

The present study revealed that the pineal gland expressed basic fibroblast growth factor (bFGF) and FGF-receptor 1 (FGFR1/flg), suggesting that bFGF in the pineal gland acts in an autocrine or paracrine manner, which is mediated by FGFR1/flg. The present study also examined gene expression of the extracellular signal-regulated kinase (ERK) family (ERK1-3) which may be intracellular signal mediators of growth factors. ERK1 [mitogen-activated protein kinase (MAP-kinase)] was strongly expressed throughout the pineal gland, while expression of ERK2 and ERK3 was not found. These findings suggest the presence of a signal pathway from bFGF to ERK1 via FGFR1/flg in the pineal gland.

Animals↗
PubMed1994

[A case of unroofed coronary sinus with persistent left superior vena cava].

A 44-year-old female with left to right shunt and persistent left superior vena cava (PLSVC) suspected of unroofed coronary sinus defect with patent right SVC and innominate vein was treated surgically. PLSVC was ligated and coronary sinus ostium was closed with a EPTFE patch. Roof defect of coronary sinus was left open and allowed the coronary venous blood to drain into the left atrium. Patient recovered well and post-operative cardiac catheterization revealed no significant right to left shunt nor desaturation of arterial blood. In the correction of unroofed coronary sinus defect and PLSVC and no other intra-cardiac defect, ligation of PLSVC and closure of coronary sinus ostium was simple and effective, although it was not anatomically corrected.

Adult↗
PubMed1993

Identification of the metabotropic glutamate receptor-1 protein in the rat trigeminal ganglion.

Anti-metabotropic glutamate receptor-1 monoclonal antibody was raised and applied for immunohistochemistry in the rat trigeminal ganglion. The antibody detected 145-kDa single band of protein in the immunoblot analysis. In immunohistochemistry, neurons in the trigeminal ganglion showed immunostaining with various intensity, almost irrespective of their cell size. The results indicate that metabotrophic glutamate receptors play an important role in somatic sensation together with ionotropic ones.

Amino Acid Sequence↗
PubMed1993

AMPA, KA and NMDA receptors are expressed in the rat DRG neurones.

The localization of AMPA receptor subunits (GluR1-4), a KA receptor subunit (GluR5) and NMDA receptor subunits (NR1 and NRgbs; the glutamate binding subunits of an NMDA receptor complex) was investigated using immunohistochemistry and in situ hybridization histochemistry in the rat dorsal root ganglion. Small neurones expressed GluR1-, GluR2/3-like immunoreactivities and GluR5, NR1, NRgbs mRNAs, while large neurones expressed GluR2/3-like immunoreactivity and NR1 and NRgbs mRNAs. These data suggest that the glutamatergic system plays an important role in the primary sensory afferent systems and that the composition of glutamate receptors differs according to the cell size.

Animals↗
PubMed1993

Expression of muscarinic and nicotinic receptor mRNA in the salivary gland of rats: a study by in situ hybridization histochemistry.

Expression of muscarinic receptor mRNA subtypes (m1-5) and nicotinic receptor subunits (alpha 2-4, and beta 2) was examined in the rat submandibular gland by in situ hybridization histochemistry, using oligonucleotide probes for the muscarinic receptor and RNA probes for the nicotinic receptors. m2, alpha 3, and beta 2 mRNA were strongly expressed in the submandibular ganglion, and m3, alpha 2, alpha 3, alpha 4, and beta 2 were expressed in the striated and interlobular duct cells. Both muscarinic and nicotinic receptors were coexpressed in the same ganglion neurons, while none of these mRNA were detected in the terminal secretory units.

Animals↗
PubMed1993

Changes in preproenkephalin mRNA after unilateral and bilateral labyrinthectomy in the rat medial vestibular nucleus.

We examined the expression of preproenkephalin (PPE) mRNA in the vestibular nuclei in rats using in situ hybridization histochemistry. In normal rats, PPE mRNA-positive cells were observed in the medial and spinal vestibular nuclei. After unilateral labyrinthectomy, PPE mRNA was increased in the medial vestibular nucleus on the operated side from the 1st through the 3rd day after the surgery. It is suggested that the changes in PPE mRNA level after labyrinthectomy are involved in vestibular compensation.

Animals↗
PubMed1993

Characteristic localization of non-NMDA type glutamate receptor subunits in the rat pituitary gland.

While the involvement of the glutamate receptors in the hypothalamo-hypophyseal system has been clarified at the hypothalamic level, the existence of glutamate receptors in the pituitary gland has remained obscure. We investigated the localization of the glutamate receptors, the non-NMDA type receptor subunits (GluR1-4) in particular, by immunocytochemistry using specific antibodies. The antibodies specific to GluR1, GluR2/3 and GluR4 exhibited the characteristic localization of the receptor molecules in each lobe of the pituitary gland. GluR1- and GluR2/3-positive cells were identified in the anterior and intermediate lobe, and intense terminals of GluR4 and weak terminals of GluR2/3 were observed in the posterior lobe. Such immunoreactivity appeared to be at the axonal terminal of the neurosecretory magnocellular cells. This was confirmed by in situ hybridization histochemistry using specific oligodeoxynucleotide probes and by immunocytochemistry in the neurosecretory magnocellular neurons. The GluR4 mRNA-positive signal and GluR4 immunoreactivity were abundantly observed in magnocells of paraventricular and supraoptic nuclei. In addition to the positive fibers, some pituicytes in the posterior lobe exhibited GluR2/3 immunoreactivity. This suggests that pituicytes have non-NMDA type glutamate receptors. Thus, present study suggests that some anterior pituitary cells and pituicytes in the neural lobe are regulated by the glutamate.

Animals↗
PubMed1993

Differential immunocytochemical localization of GABAA receptor gamma 1 and gamma 2 subunits in the rat brain.

Subunit-specific polyclonal antisera against the GABAA receptor gamma 1 and gamma 2 subunits were raised in rabbits and used for immunoblotting and immunocytochemistry of the rat brain. Each subunit protein was differentially distributed even in the region like cerebellar cortex where mRNAs of both subunits were distributed in the same manner. This may indicate that GABAA receptor gamma 1 and gamma 2 subunit proteins are subject to a subunit-specific subcellular sorting mechanism.

Amino Acid Sequence↗
PubMed1993

Synaptic contact between vestibular afferent nerve and cholinergic efferent terminal: its putative mediation by nicotinic receptors.

The topography and fine structure of cholinergic efferent fibers were examined in the rat vestibular labyrinth using choline acetyltransferase (ChAT) immunohistochemistry. Fiber plexus of cholinergic fibers were observed beneath the sensory cell layer in all vestibular end-organs. Electron microscopic examination revealed that cholinergic fibers make synaptic contacts with chalices of vestibular nerve branches that surround type I hair cells. In situ hybridization histochemistry of nicotinic acetylcholine receptor subunit mRNAs showed that rat vestibular ganglion cells express both alpha 4 and beta 2 subunit mRNAs. These findings suggest that cholinergic efferents modulate vestibular information from type I hair cells by nicotinic receptors at the level of nerve chalices.

Acetylcholine↗
PubMed1993

Sympathetic and parasympathetic ganglia express non-NMDA type glutamate receptors: distinct receptor subunit composition in the principle and SIF cells.

The presence of non-NMDA glutamate receptors in the rat sympathetic and parasympathetic ganglia was examined by immunocytochemistry using specific antibodies against AMPA-type excitatory amino acid receptor subunits (GluR1-4). Three kinds of antibodies specific to the GluR1, GluR2 and 3, and GluR4 subunits were used. The superior cervical ganglion and pterygopalatine ganglion were examined as representatives of sympathetic and parasympathetic ganglia. In the superior cervical ganglion, GluR1- and GluR2/3-like immunoreactivity was observed in most principal neurons and SIF cells. In contrast, GluR4-like immunoreactivity was not observed in the principal cells; however, SIF cells exhibited intense immunoreactivity of GluR4. In the pterygopalatine ganglion, the profile of the immunoreactivity was similar to that seen in the superior cervical ganglia. The subunit compositions between the principal cells and SIF cells were different, whereas the compositions in cell species involved in the autonomic ganglia, sympathetic and parasympathetic ganglia were identical. This suggests that glutamate is another important preganglionic transmitter together with acetylcholine, and the responses elicited in the principal cells and SIF cells might be different because of the difference in subunit composition.

Animals↗