Biomedical subjects

N Mizuno

Publications and source records attributed to N Mizuno.

At least 109 records · Page 6Linked to original sources

PubMed1997

Binding of the isolectin I-B4 from Griffonia simplicifolia to the general visceral afferents in the vagus nerve: a light- and electron-microscope study in the rat.

Prominent binding to the isolectin I-B4 from Griffonia simplicifolia (I-B4) was observed not only in the terminal area of general somatic afferents (lamina II of the medullary and the spinal dorsal horns), but also in the terminal area of the general visceral afferents (nucleus of the solitary tract, NST). The vast majority of neuronal cell bodies in the nodose ganglion (NG), including those with substance P-like immunoreactivity, also showed the I-B4-binding. After ganglionectomy of the NG, the I-B4-binding in the solitary tract and NST was highly reduced throughout the solitary tract and the NST on the side ipsilateral to the operation. The I-B4-binding was electron microscopically observed in many axon terminals within the NST.

Animals↗

PubMed1997

Parabrachial nucleus neurons providing axons to both the thalamus and the spinal cord in the rat.

After injecting Fluoro-gold (FG) and tetramethylrhodamine-dextran amine (TMR-DA), respectively, into the medial part of the ventrobasal thalamus and the upper segments of the cervical cord of the rat, a small number of neuronal cell bodies were double-labeled retrogradely with both FG and TMR-DA in the parabrachial nuclear complex (BPN) ipsilateral to the injection into the thalamus. The cell bodies double-labeled with FG/TMR-DA were seen mainly in the Kölliker-Fuse subnucleus and additionally in the external medial subnucleus.

Animals↗

PubMed1997

Localisation of neurokinin 3 (NK3) receptor immunoreactivity in the rat gastrointestinal tract.

The localisation of the neurokinin 3 receptor (NK3r) in the rat gastrointestinal tract has been studied by using a polyclonal antiserum against the C-terminal portion (amino acids 388-452) of the rat NK3r. In the oesophagus, immunoreactivity for the NK3r was found on smooth muscle cells of the muscularis mucosae. NK3r immunoreactivity was not present on muscle cells of other regions. Nerve cell bodies immunoreactive for NK3r were seen in the myenteric and submucous plexuses of the small and large intestine, but not in the stomach or oesophagus. Immunoreactivity was largely confined to nerve cell surfaces. The reaction product was on the cell soma and initial parts of axons. Reactivity was not seen on nerve terminals. Immunoreactive nerve cells had Dogiel Type II morphology. Patterns of co-localisation of NK3r and immunoreactivity for other markers were examined in the ileum, to provide a basis from which to deduce the functional identity of NK3r-immunoreactive nerve cells. Most of the NK3r-immunoreactive nerve cells were also immunoreactive for the calcium-binding proteins, calretinin and calbindin, and all were immunoreactive for the NK1 receptor (NK1r). Nerve cells that were immunoreactive for nitric oxide synthase were not immunoreactive for either NK3r or NK1r. The projections of the calbindin and calretinin neurons were determined by nerve lesion studies. Their morphology, projections to the mucosa and other ganglia and immunoreactivity for the calcium-binding proteins suggest that the NK3r-immunoreactive neurons are intrinsic sensory neurons.

Animals↗

PubMed1997

Single neurons in the spinal trigeminal and dorsal column nuclei project to both the cochlear nucleus and the inferior colliculus by way of axon collaterals: a fluorescent retrograde double-labeling study in the rat.

A number of single neurons in the spinal trigeminal nucleus (STN) and the dorsal column nucleus (DCN) were found to project simultaneously to the cochlear nucleus (CoN) and the external cortex of the inferior colliculus (ICe) by way of axon collaterals. Each rat was injected with Fluoro-Gold (FG) into CoN on one side and with tetramethylrhodamine-dextran amine (TMR-DA) into ICe on the side ipsilateral or contralateral to the FG injection. In these rats, a number of neuronal cell bodies in DCN and the interpolar and caudal subnuclei of STN were double-labeled retrogradely with both FG and TMR-DA, mainly on the side ipsilateral to the FG injection into CoN. These neurons in STN and DCN might mediate somatosensory inputs simultaneously to the two lower brainstem nuclei, CoN and ICe, which constitute the relays of the auditory pathway.

Animals↗

PubMed1997

Topographic distribution and collateral projections of the two major populations of nigrothalamic neurons. A retrograde labeling study in the rat.

The principal target nuclei of nigrothalamic projections in the rat are the mediodorsal (MD) and ventromedial (VM) nuclei. The present study examined the patterns of distribution and collateral projections of the two major groups of nigrothalamic neurons, i.e., nigro-MD and nigro-VM neurons. Retrograde fluorescent labeling with Fluoro-Gold was used to examine whether the distribution areas of nigro-MD and nigro-VM neurons might be overlapped with or segregated from each other in the substantia nigra pars reticulata. A clear tendency was observed that nigro-MD neurons were distributed more ventrally than nigro-VM neurons. It was further examined by retrograde fluorescent double labeling with Fluoro-Gold and Fluoro-Ruby whether or not these nigrothalamic neurons might provide axon collaterals to the superior colliculus or the pontine reticular formation. The nigro-MD neurons were found to send axon collaterals to the superior colliculus more frequently than the nigro-VM neurons. Additionally, a small number of nigrothalamic neurons were found to send axon collaterals to the pontine reticular formation. The functional significance of the two major populations of nigrothalamic neurons was discussed on the basis of their collateral projections to the superior colliculus or the pontine reticular formation.

Animals↗

PubMed1997

Trajectory formation of the center-of-mass of the arm during reaching movements.

We attempted to identify the invariant kinematic properties of multijoint arm reaching movements in the horizontal plane to explore the planning variable(s) involved in their coordination. Different targets were placed near the perimeter of the workspace boundary, thereby causing variation of size and orientation of the hand stroke. We have a special interest in the trajectory characteristics of the most massive point within the arm system, the center-of-mass of the entire arm system, in addition to those of the hand or joints. The motion of the individual segments (the forearm plus hand and the upper arm) or joints (shoulder and elbow) was modulated in a different way depending on the tasks; thus, there was no invariance in the relationships between paired variables (displacement or velocity) for segment or joint motions. For relatively short hand strokes, the trajectory of the hand and the center-of-mass of the entire arm system were characterized by a nearly straight path, and a smooth, bell-shaped velocity curve along the path, symmetrical about the mid-portion of the movement, starting from nearly zero, growing to a single peak and declining again to nearly zero. However, in large hand strokes the hand path was highly curved and the velocity curve was asymmetric. Although the path of the center-of-mass of the entire arm system also tended to be curved with the increase of the hand stroke, a bell-shaped velocity curve along the path and its typical symmetry were preserved over a wide range of stroke sizes and orientations, and its peak was scaled in proportion to movement distance and movement time. Our findings indicate that it is not valid to postulate solely the joint- or hand-based planning strategies which have been proposed previously. Rather, the planning of the spatial aspects of the motion is largely dependent on the interaction of multiple variables, including those not analysed in this study. The bell-shaped pattern of the center-of-mass velocity profile represents a certain efficiency of movement, since it corresponds to a single accelerative and a decelerative phase of a mass over the movement, with no intermediate force reversals. The simple structure of the center-of-mass velocity profiles may reflect a fundamental organization principle underlying the temporal aspects of movement planning.

Adult↗

PubMed1996

Spiny stellate neurones in layer VI of the rat cerebral cortex.

From 109 neurones labelled intracellularly in layer VIa of rat neocortical slices, four non-pyramidal, spiny stellate neurones were identified by their common morphological characteristics. They had a small cell body and densely spiny dendrites extending radially, but no dominant apical dendrite. The main axons ran briefly to the pial surface, and then made a characteristic U-turn to descend toward the white matter. In immunofluorescence cytochemistry, all the spiny stellate neurones were immunopositive for glutaminase but not for calcium-binding proteins, suggesting that they were glutamatergic. Electrophysiologically, they belonged to the regular spiking type and showed a small fast afterhyperpolarization. Thus, the spiny stellate neurones were considered to represent a unique group of excitatory neurones in layer VI of the cerebral cortex.

Animals↗

PubMed1996

GABAergic and glycinergic neurons projecting to the trigeminal motor nucleus: a double labeling study in the rat.

The distribution of GABAergic and glycinergic premotor neurons projecting to the trigeminal motor nucleus (Vm) was examined in the lower brainstem of the rat by a double labeling method combining retrograde axonal tracing with immunofluorescence histochemistry. After injection of the fluorescent retrograde tracer, tetramethylrhodamine dextran amine (TRDA), into the Vm unilaterally, neurons labeled with TRDA were seen ipsilaterally in the mesencephalic trigeminal nucleus, and bilaterally in the parabrachial region, the supratrigeminal and intertrigeminal regions, the reticular formation just medial to the Vm, the principal sensory and spinal trigeminal nuclei, the pontine and medullary reticular formation, especially the parvicellular part of the medullary reticular formation, the alpha part of the gigantocellular reticular nucleus, and the medullary raphe nuclei. Some of these neurons labeled with TRDA were found to display glutamic acid decarboxylase (the enzyme involved in GABA synthesis)-like or glycine-like immunoreactivity. Such double-labeled neurons were seen mainly in the supratrigeminal region, the reticular region adjacent to the medial border of the Vm, and the dorsal part of the lateral reticular formation of the medulla oblongata; a number of them were further scattered in the intertrigeminal region, the alpha part of the gigantocellular reticular nucleus, the nucleus raphe magnus, the principal sensory trigeminal nucleus, and the interpolar subnucleus of the spinal trigeminal nucleus. These neurons were considered to be inhibitory (GABAergic or glycinergic) neurons sending their axons to motoneurons in the Vm, or to local interneurons within and around the Vm.

Animals↗

PubMed1996

Effects of peripheral nerve ligation on expression of mu-opioid receptor in sensory ganglion neurons: an immunohistochemical study in dorsal root and nodose ganglion neurons of the rat.

The present study was attempted to examine if mu-opioid receptor (MOR) might be transported by axonal flow peripherally through peripheral axons of somatic sensory ganglion neurons. After unilateral ligation of the sciatic nerve or the vagus nerve distal to the dorsal root ganglion (DRG) or nodose ganglion (NG), MOR-like immunoreactivity (MOR-LI) of neuronal cell bodies in the DRG of the fourth and fifth lumbar nerves, NG, ambiguus nucleus (Amb) and dorsal motor nucleus of the vagus nerve (DMV) on the side of the ligation was apparently reduced within 1 week after the nerve ligation. However, within 24 h after the nerve ligation, a transient enhancement of MOR-LI was observed in cell bodies of DRG neurons, sciatic nerve stump proximal to the ligature, and cell bodies of NG neurons on the side of the ligation; such a transient enhancement of MOR-LI was not detected in the Amb and DMV. The results suggest that MOR undergoes centrifugal axonal flow in peripheral axons of somatic and visceral sensory ganglion neurons, and that MOR synthesis in sensory ganglion neurons is vulnerable to damage of the peripheral axons.

Analgesics, Opioid↗

PubMed1996

Patchy distribution of substance P receptor immunoreactivity in the' developing rat striatum.

Developmental changes of the distribution pattern of substance P receptor (SPR) were investigated immunohistochemically in the rat striatum. The SPR immunoreactivity in the striatum first emerged at postnatal day 1 and transiently showed a patchy pattern of distribution until it displayed the adult pattern of homogeneous distribution by the third postnatal week. The SPR-immunoreactivity patches were most marked in the medial and dorsolateral parts of the striatum, as well as in the subcallosal streak. They matched tyrosine hydroxylase-enriched areas and, conversely, avoided calbindin-enriched zones. No neurons within the SPR-immunoreactive patches contained either choline acetyltransferase or somatostatin, which is known to be contained in intrinsic neurons in the striatum. The vast majority of SPR-immunoreactive patch neurons also contained DARPP-32, a phosphoprotein that is expressed in striatal projection neurons with D1 dopamine receptor. The results indicate that SPR-immunoreactive patches which appear transiently in the developing striatum are in register with the striatal patch compartment, and that SPR immunoreactivity within these patches may be expressed on projection neurons rather than intrinsic neurons. Such SPR immunoreactivity in projection neurons in striatal patches may fade out in adulthood.

Animals↗

PubMed1996

Distribution of the mRNA for a pituitary adenylate cyclase-activating polypeptide receptor in the rat brain: an in situ hybridization study.

The distribution of the mRNA for a pituitary adenylate cyclase-activating polypeptide (PACAP) receptor (PACAP-R) was examined in the rat brain, and also in the hypophysis and pineal gland, by in situ hybridization with a specific 35S-labeled riboprobe which was generated from a rat PACAP-R cDNA clone. In the brain, expression of PACAP-R mRNA was most prominent in the periglomerular and granule cells of the olfactory bulb, granule cells of the dentate gyrus, supraoptic nucleus, and area postrema. The expression was also intense in the piriform, cingulate, and retrosplenial cortices, pyramidal cells in CA2, non-pyramidal cells in CA1-CA3, neuronal cells in the hilus of the dentate gyrus, lateral septal nucleus, intercalated amygdaloid nucleus, anterodorsal thalamic nucleus, most of the midline and intralaminar thalamic nuclei, many regions of the hypothalamus, dorsal motor nucleus of the vagus nerve, hypoglossal nucleus, and lateral reticular nucleus. No significant expression was detected in the mitral and tufted cells in the olfactory bulb, pyramidal cells in CA1 and CA3, posterior nuclear group of the thalamus, dorsal lateral geniculate nucleus, and Purkinje, Golgi, and granule cells in the cerebellar cortex. Moderate-to-weak expression was further observed in many other regions of the brain. In the cerebellar cortex, presumed Bergmann glia cells showed moderate expression. In the hypophysis, the expression was moderate in the anterior lobe, and weak to moderate in the posterior lobe; no significant expression was observed in the intermediate lobe. In the pineal gland, the expression was very weak, if any. Thus, the expression of PACAP-R was detected not only on neuronal cells but also on some particular glial cells. The present study has shown, for the first time, the exact site of PACAP-R expression in the brain and hypophysis. Although the functional significance of PACAP and PACAP-R in the brain still remains to be clarified, the present results are considered to provide some direction for future functional studies.

Animals↗

PubMed1996

GABAergic synapses upon neurons expressing substance P receptors in the nucleus of the solitary tract: an immunocytochemical electron microscope study in the rat.

Morphological substrates for interactions between gamma-aminobutyric acid (GABA) and substance P upon neurons expressing substance P receptor (SPR) in the nucleus of the solitary tract (NST) were investigated by immunocytochemical electron microscopy. In the NST of the rat, many GABA-like immunoreactive axon terminals were in symmetric synaptic contacts with dendritic profiles; they were observed on nearly a half of the SPR-like immunoreactive dendritic profiles in the medial part of the caudal half of the NST.

Animals↗

PubMed1996

Distribution of trigeminothalamic and spinothalamic-tract neurons showing substance P receptor-like immunoreactivity in the rat.

Trigeminothalamic and spinothalamic-tract neurons provided with substance P receptor (SPR) were examined in the rat by SPR immunofluorescence histochemistry combined with Fluoro-Gold (FG) fluorescent retrograde labeling. After FG injection in the thalamic regions, FG-labeled cells with SPR-like immunoreactivity were seen mainly in laminae I and III of the medullary and spinal dorsal horns and lateral spinal nucleus. In these regions, about one-fourth to one-third of FG-labeled cells showed SPR-like immunoreactivity.

Afferent Pathways↗

PubMed1996

Immunohistochemical localization of mu-opioid receptors in the central nervous system of the rat.

Of the three major types of opioid receptors ( mu, delta, kappa) in the nervous system, mu-opioid receptor shows the highest affinity for morphine that exerts powerful effects on nociceptive, autonomic, and psychological functions. So far, at least two isoforms of mu-opioid receptors have been cloned from rat brain. The present study attempted to examine immunohistochemically the distribution of mu-opioid receptors in the rat central nervous system with two kinds of antibodies to recently cloned mu-opioid receptors (MOR1 and MOR1B). One antibody recognized a specific site for MOR1, and the other bound to a common site for MOR1 and MOR1B. Intense MOR1-like immunoreactivity (LI) was seen in the 'patch' areas and subcallosal streak in the striatum, medial habenular nucleus, medial terminal nucleus of the accessory optic tract, interpeduncular nucleus, median raphe nucleus, parabrachial nuclei, locus coeruleus, ambiguous nucleus, nucleus of the solitary tract, and laminae I and II of the medullary and spinal dorsal horns. Many other regions, including the cerebral cortex, amygdala, thalamus, and hypothalamus, also contained many neuronal elements with MOR1-LI. The distribution pattern of the immunoreactivity revealed with the antibody to the common site for MOR1 and MOR1B (MOR1/1B-LI) was almost the same as that of MOR1-LI. Both MOR1-LI and MOR1/1B-LI were primarily located in neuronal cell bodies and dendrites. However, the immunoreactivities were observed in the accessory optic tract, fasciculus retroflexus, solitary tract, and primary afferent fibers in the superficial layers of the medullary and spinal dorsal horns. The presynaptic location of MOR1-LI and MOR1/1B-LI was confirmed by lesion experiments: Enucleation, placing a lesion in the medial habenular nucleus, removal of the nodose ganglion, or dorsal rhizotomy resulted in a clear reduction of the immunoreactivities, respectively, in the nuclei of the accessory optic tract, some subnuclei of the interpeduncular nucleus, nucleus of the solitary tract, or laminae I and II of the spinal dorsal horn. The results indicate that the mu-opioid receptors are widely distributed in the brain and spinal cord, mainly postsynaptically and occasionally presynaptically. Opioids, including morphine, may inhibit the excitation of neurons via the postsynaptic mu-opioid receptors, and also suppress the release of neurotransmitters and/or neuromodulators from axon terminals through the presynaptic mu-opioid receptors.

Amino Acid Sequence↗

PubMed1996

Presynaptic localization of a metabotropic glutamate receptor, mGluR4a, in the cerebellar cortex: a light and electron microscope study in the rat.

Localization of a metabotropic glutamate receptor, mGluR4a, was immunohistochemically examined in the rat cerebellum with an antibody, which was produced by using a synthetic peptide corresponding to a C-terminal sequence of rat mGluR4a. Marked mGluR4a-like immunoreactivity (mGluR4a-LI) was seen in neuropil of the molecular layer of the cerebellar cortex. Electron microscopically, mGluR4a-LI was observed in many axon terminals in the molecular layer. These axon terminals showing mGluR4a-LI were filled with round synaptic vesicles and were in asymmetric synaptic contacts most frequently with dendritic spines. The results indicate that mGluR4a are located presynaptically in the parallel fibers arising from the granule cells in the cerebellar cortex.

Animals↗

PubMed1996

Presynaptic localization of a metabotropic glutamate receptor, mGluR8, in the rhinencephalic areas: a light and electron microscope study in the rat.

The present study indicated presynaptic localization of a metabotropic glutamate receptor, mGluR8, in projection neurons of the main olfactory bulb of rat. An antibody was produced by using a peptide corresponding to C-terminal 23 amino acids of mouse mGluR8. It was confirmed that the C-terminal 23 amino acids of rat mGluR8 were the same as those of mouse mGluR8 except for one, and that the antibody specifically recognized mGluR8 in the rat rhinencephalon. In layer Ia of the piriform cortex (a target area of projection fibers from the main olfactory bulb), mGluR8-like immunoreactivity (mGluR8-LI) was reduced after transection of the lateral olfactory tract, and mGluR8-LI was observed in axon terminals which were filled with round synaptic vesicles and made asymmetric synapses with dendritic spines.

Animals↗

PubMed1996

Immunohistochemical localization of a metabotropic glutamate receptor, mGluR7, in ganglion neurons of the rat; with special reference to the presence in glutamatergic ganglion neurons.

Immunoreactivity for the metabotropic glutamate receptor 7 (mGluR7) and that for phosphate-activated glutaminase (PAG) were examined in the trigeminal (TG), dorsal root (DRG), nodose (NG), superior cervical, celiac, and pelvic ganglia of the rat. Virtually all neuronal cell bodies showed mGluR7-like immunoreactivity (mGluR7-LI) in these ganglia. On the other hand, PAG-like immunoreactivity (PAG) was seen in almost all neuronal cell bodies in the TG, DRG and NG, but not in the other ganglia. Co-existence of mGluR7- and PAG-LI in the TG, DRG and NG was confirmed by a double-immunofluorescence immunohistochemical method. The results indicate that virtually all sensory ganglion neurons are glutamatergic and equipped with mGluR7.

Animals↗

PubMed1996

Localization of the neuromedin K receptor (NK3) in the central nervous system of the rat.

The distribution of the neuromedin K receptor (NK3; NKR) in the central nervous system was investigated in the adult rat by using in situ hybridization and immunohistochemical techniques. The rabbit anti-NKR antibody was raised against a bacterial fusion protein containing a C-terminal portion of NKR and affinity purified with a Sepharose 4B column conjugated to the fusion protein. Immunoblot analysis was performed to test the reactivity and specificity of the antibody. Crude membrane was prepared from cDNA-transfected Chinese hamster ovary (CHO) cells expressing each of the rat NKR, substance P receptor (NK1; SPR), and substance K receptor (NK2; SKR) and from the hypothalamus, cerebral cortex, and cerebellum. Immunoreactive bands were observed specifically in the NKR-CHO cells, hypothalamus, and cerebral cortex but not in the SPR- or SKR-CHO cells, nor in the cerebellum. Molecular weights of the immunoreactive bands ranged from 73 to 89 kDa and from 59 to 83 kDa in the NKR-CHO cells and tissues, respectively. The distribution of NKR-like immunoreactivity coincided with that of NKR mRNA. The expression of NKR was indicated on neuronal cell bodies and dendrites. NKR was found to be expressed intensely or moderately in neurons in the glomerular and granule cell layers of the main olfactory bulb; glomerular and mitral cell layers of the accessory olfactory bulb; layers IV and V of the cerebral neocortex; medial septal nucleus; nucleus of the diagonal band; bed nucleus of the stria terminalis; globus pallidus; ventral pallidum; paraventricular nucleus; supraoptic nucleus; zona incerta; dorsal, lateral, and posterior hypothalamic areas; amygdaloid nuclei; medial habenular nucleus; ventral tegmental area; midbrain periaqueductal gray; interpeduncular nuclei; substantia nigra pars compacta; linear, median, dorsal, and pontine raphe nuclei; posteromedial tegmental nucleus; sphenoid nucleus; nucleus of the solitary tract; intermediate and rostroventrolateral reticular nuclei; and lamina II of the caudal spinal trigeminal nucleus and spinal dorsal horn. These findings are discussed in relation to the physiological functions associated with neuromedin K.

Animals↗