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Y Yoshihara

Publications and source records attributed to Y Yoshihara.

At least 73 records · Page 4Linked to original sources
PubMed1994

Development of glomerular structure in rabbit olfactory bulb: three-dimensional reconstruction under the confocal laser scanning microscopy.

Confocal laser scanning imaging was used to reconstruct the three-dimensional distribution of the aggregates of olfactory receptor axons terminating within individual glomeruli in the rabbit main olfactory bulb. Two monoclonal antibodies, R2D5 and R4B12, were used to mark selectively the olfactory receptor axons. Thick coronal sections (100-200 microns in thickness) through the bulb were labeled with either of the antibodies, and then serial optical sectioning was performed to reconstruct three-dimensional optic images of the labeled axons in the glomeruli. The results revealed an intricate internal structure of the glomeruli with a mesh-like arrangement of bundles of terminal olfactory axons. Developmental study showed that primitive glomeruli lacking the internal structure of the adult form first appear in the 22-day embryo and that the characteristic internal structure of the glomeruli develops mainly during postnatal days. The confocal laser scanning image method together with specific molecular markers provides a simple tool for the three-dimensional analysis of the glomerular structure.

Age Factors↗
PubMed1994

Telencephalin: a neuronal area code molecule?

Cell adhesion molecules (CAMs) with expression restricted to specific developmental and structural units of the brain and/or selective neuronal types would play critical roles in the formation of functional neuronal networks. In this article, we summarize recent progress in knowledge on a brain segment-specific CAM, telencephalin (TLN). TLN has the following characteristic properties. (1) TLN is a neuronal glycoprotein whose expression is restricted within telencephalon, the most rostal segment of the brain. (2) TLN is localized to the soma-dendritic membrane of subsets of telencephalic neurons, but not to the axonal membrane. (3) Abrupt appearance of TLN around birth parallels the timing of dendritic development and synapse formation in the telencephalon. (4) TLN belongs to the immunoglobulin superfamily and its structure is most closely related to intercellular adhesion molecules (ICAMs)-1 and -3. These findings suggest that TLN is the first example of dendrite-associated cell adhesion molecules (DenCAMs) and that TLN may be involved in the brain segmental organization, cell-cell interactions during dendritic development, and maintenance of functional neuronal networks. We discuss the possibility that TLN is an area code-like address signal that is displayed selectively by telencephalic neurons and is decoded by specific subsets of growing axons to make proper synaptic connections.

Animals↗
PubMed1994

An ICAM-related neuronal glycoprotein, telencephalin, with brain segment-specific expression.

Telencephalin (TLN) is a 130 kd glycoprotein expressed exclusively in neurons of the telencephalon, the most rostral brain segment. In the neurons, TLN is localized to soma-dendritic membrane but not to axonal membrane. In this study, we have cloned cDNA encoding rabbit and mouse TLN. The cDNA-derived primary structure of TLN predicts an integral membrane protein with nine tandem immunoglobulin-like domains in an extra-cellular region, a transmembrane domain, and a short cytoplasmic tail. The distal eight immunoglobulin-like domains of TLN show highest homology with the immunoglobulin-like domains of intracellular adhesion molecules (ICAMs) 1, 2, and 3/R. The structural similarity of TLN with ICAMs provides a new and strong link between immunoglobulin superfamily molecules in the nervous and immune systems. TLN is an example of a dendrite-associated cell adhesion molecule involved in the brain's segmental organization, cell-cell interactions during dendritic development, and maintenance of functional neuronal networks.

Amino Acid Sequence↗
PubMed1994

BIG-1: a new TAG-1/F3-related member of the immunoglobulin superfamily with neurite outgrowth-promoting activity.

We have cloned a rat cDNA for a novel brain-derived immunoglobulin (Ig) superfamily molecule, BIG-1, by using PCR based on the amino acid sequences of the two closely related and well-known Ig superfamily members, rat TAG-1 and mouse F3. BIG-1 is a glycosylphosphatidylinositol-anchored membrane protein with six Ig-like domains and four fibronectin type III repeats, belonging to the TAG-1/F3 subgroup. The expression of BIG-1 mRNA is developmentally regulated with the highest level in the adult brain. It is restricted to subsets of neurons such as Purkinje cells of the cerebellum, granule cells of the dentate gyrus, and neurons in the superficial layers of the cerebral cortex. Recombinant BIG-1 protein has a neurite outgrowth-promoting activity when used as a substrate for neurons in vitro. These results suggest that BIG-1 may be involved in the formation and maintenance of neuron type-specific networks in the brain.

Amino Acid Sequence↗
PubMed1993

Expression of prostaglandin endoperoxide synthase in rat brain.

Developmental and regional expression of prostaglandin endoperoxide synthase (PES) transcript was examined in the rat brain and in primary mixed cultures of neurons and glial cells from neonatal brain. Although the PES mRNA level in the brain was much lower than that in peripheral rat tissues such as lung, liver, spleen and kidney, a significant 3.0 kb band was detected in brain samples by Northern blot analysis. During development, PES mRNA was first detectable at postnatal day 7, and increased thereafter toward adulthood. The highest level of 3.0 kb PES mRNA was observed in the olfactory bulb, midbrain, and hypothalamus; and the lowest level in the hippocampus. In primary cultures of neonatal brain cells, the level of 3:0 kb transcript of PES transiently and dramatically increased about 30-fold on the third day after plating. Simultaneously, two cross-hybridizing signals were detected at 4.0 and 7.0 kb. This increase in PES mRNAs was completely inhibited by addition of cytosine-1-beta-D-arabinofuranoside. The induction of PES mRNA was in parallel with the increase in PES protein, as assessed by Western blot analysis. Immunostaining of cultured cells with anti-PES monoclonal antibody revealed that PES protein was induced mainly in neurons but not in glial cells. These results suggest that PES is expressed in the central nervous system at a low concentration under normal conditions, and that the neuronal cells possess an ability to express high levels of PES mRNA and protein.

Aging↗
PubMed1993

Odor stimulation causes disappearance of R4B12 epitope on axonal surface molecule of olfactory sensory neurons.

Monoclonal antibodies R4B12 and R1D1 label the same subsets of rabbit primary olfactory axons. In the present study, we characterized the R4B12 antigens using immunohistochemical, immunoelectron-microscopic, and biochemical techniques. The R4B12 antigens are expressed on the surface membrane of a subset of primary olfactory axons. Western blot analysis revealed the existence of two forms (115,000 and 90,000 mol.wt) of the R4B12 antigens with different membrane-anchoring structures. Of the two forms, the smaller antigen (90,000 mol. wt) is anchored to the plasma membrane via a phosphatidylinositol linkage and expressed exclusively by the olfactory system. When the rabbit olfactory epithelium was stimulated by odors for 2-8 h in situ, the R4B12 immunoreactivity disappeared from the primary olfactory axons in the glomeruli of the olfactory bulb. These results suggest that the cell surface antigens R4B12 expressed by subsets of primary olfactory axons undergo stimulus-dependent changes by odor stimulation and may be involved in plasticity of olfactory sensory neurons.

Animals↗
PubMed1993

Joint fluid carboxy-terminal type II procollagen peptide as a marker of cartilage collagen biosynthesis.

Joint fluid levels of carboxy-terminal type II procollagen peptide (pCOL II-C) were measured in osteoarthritis, rheumatoid arthritis and traumatic arthritis by a newly developed one-step enzyme immunoassay (EIA). The detection limit of the new method was as low as 0.2 ng/ml. The levels of pCOL II-C were significantly (P < 0.001) higher in osteoarthritis and traumatic arthritis than in rheumatoid arthritis. In osteoarthritis, pCOL II-C levels were higher in moderately afflicted patients. Since type II collagen is a unique component of cartilage, pCOL II-C levels in joint fluids could reflect the synthetic activity of type II collagen of chondrocytes in the diseased joint and therefore could be utilized as a simple marker of type II collagen synthesis in articular cartilage in joint diseases.

Adult↗
PubMed1993

R2D5 antigen: a calcium-binding phosphoprotein predominantly expressed in olfactory receptor neurons.

R2D5 is a mouse monoclonal antibody that labels rabbit olfactory receptor neurons. Immunoblot analysis showed that mAb R2D5 recognizes a 22-kD protein with apparent pI of 4.8, which is abundantly contained in the olfactory epithelium and the olfactory bulb. We isolated cDNA for R2D5 antigen and confirmed by Northern analysis and neuronal depletion technique that R2D5 antigen is expressed predominantly, but not exclusively, in olfactory receptor neurons. Analysis of the deduced primary structure revealed that R2D5 antigen consists of 189 amino acids with calculated M(r) of 20,864 and pI of 4.74, has three calcium-binding EF hands, and has possible phosphorylation sites for Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) and cAMP-dependent protein kinase (A kinase). Using the bacterially expressed protein, we directly examined the biochemical properties of R2D5 antigen. R2D5 antigen binds Ca2+ and undergoes a conformational change in a manner similar to calmodulin. R2D5 antigen is phosphorylated in vitro by CaM kinase II and A kinase at different sites, and 1.81 and 0.80 mol of Pi were maximally incorporated per mol of R2D5 antigen by CaM kinase II and A kinase, respectively. Detailed immunohistochemical study showed that R2D5 antigen is also expressed in a variety of ependymal cells in the rabbit central nervous system. Aside from ubiquitous calmodulin, R2D5 antigen is the first identified calcium-binding protein in olfactory receptor neurons that may modulate olfactory signal transduction. Furthermore our results indicate that olfactory receptor neurons and ependymal cells have certain signal transduction components in common, suggesting a novel physiological process in ependymal cells.

Animals↗
PubMed1993

The complete amino acid sequence of subunit d of rat liver mitochondrial H(+)-ATP synthase.

Subunit d of H(+)-ATP synthase from rat liver mitochondria was isolated from the purified enzyme by reverse-phase high performance liquid chromatography. The partial amino acid sequence of the subunit was determined by automated Edman degradation of the peptide fragments. The nucleotide sequence of subunit d of rat liver H(+)-ATP synthase was determined from a recombinant cDNA clone isolated by screening a rat hepatoma cell line H4TG cDNA library with a probe DNA. The sequence was composed of 581 nucleotides including a coding region for the import precursor of subunit d and noncoding regions on the 5'- and 3'- sides. The possible precursor of subunit d and its mature polypeptide deduced from the open reading frame consisted of 161 and 160 amino acid residues with molecular weights of 18,763 and 18,631, respectively. Subunit d is a hydrophilic protein with an isoelectric point of 6.19. The sequence of the rat subunit d is highly homologous with that of subunit d of bovine heart and slightly similar to that of the subunit d of the yeast mitochondria. However, it had no homology with the sequence of any of the subunits of bacterial or chloroplast H(+)-ATP synthase.

Amino Acid Sequence↗
PubMed1992

Complete amino acid sequence of subunit e of rat liver mitochondrial H(+)-ATP synthase.

Subunit e of H(+)-ATP synthase from rat liver mitochondria was isolated from the purified enzyme by reverse-phase high-performance liquid chromatography. The amino acid sequence of the subunit was determined by automated Edman degradation of the whole protein and derived peptides. The nucleotide sequence of the import precursor of subunit e of rat liver H(+)-ATP synthase was determined from a recombinant cDNA clone isolated by screening a rat hepatoma cell line H4TG cDNA library with a probe DNA. The sequence was composed of 289 nucleotides including a coding region for the import precursor of subunit e and noncoding regions on the 5'- and 3'-sides. The possible import precursor of subunit e and its mature polypeptide deduced from the open reading frame consisted of 71 and 70 amino acid residues with molecular weights of 8254 and 8123, respectively. Subunit e is a basic hydrophilic protein with an isoelectric point of 9.78. The sequence of the rat subunit e is highly homologous with that of subunit e of bovine heart, but has no homology with any subunit of bacterial or chloroplast H(+)-ATP synthase. The function of subunit e is unknown. However, a homology search in the database of the National Biomedical Research Foundation revealed that residues 34-65 of subunit e are homologous with residues 90-117 of troponin T, and with residues 529-561 of h-caldesmon and residues 289-319 of l-caldesmon, which are the homologous sequences corresponding to the Ca(2+)-dependent tropomyosin-binding region of troponin T.

Amino Acid Sequence↗
PubMed1992

A simple, rapid method for purification of epsilon-subunit, coupling factor 6, subunit d, and subunit e from rat liver H(+)-ATP synthase and determination of the complete amino acid sequence of epsilon-subunit.

The rat liver mitochondrial epsilon-subunit, coupling factor 6, subunit d, and subunit e of H(+)-ATP synthase, which are all extra subunits with no counterparts in Escherichia coli, were purified by reverse-phase high performance liquid chromatography. The complete amino acid sequence of the rat epsilon-subunit was determined by automated Edman degradation of the whole protein and derived peptides. The protein contains 50 amino acids and has a molecular mass of 5635 kDa. It is a basic hydrophilic protein with an isoelectric point of 10.5. The sequence of the rat epsilon-subunit is highly homologous with that of the epsilon-subunit of bovine heart and slightly similar to those of the epsilon-subunit of the yeast and sweet potato mitochondria. However, it has no homology with any subunit of bacterial or chloroplast H(+)-ATP synthase.

Amino Acid Sequence↗
PubMed1992

Ontogeny of cytosolic phospholipase A2 activity in rat brain.

We investigated developmental changes in the activity of cytosolic phospholipase A2 (cPLA2) in the rat brain. When the cytosolic fractions from rat brain of various ages were examined by gel filtration chromatography, cPLA2 activity was detected at about 100 kDa in all developmental stages. However, the magnitude of cPLA2 activity differed significantly. The cPLA2 activity was highest in the brain of day-12 embryo, gradually decreased toward birth, and retained a constant level into adulthood. This result suggests that cPLA2 plays an important role in the early development of the nervous system.

Aging↗
PubMed1992

Increase in cytoplasmic free Ca2+ elicited by noradrenalin and serotonin in cultured local interneurons of mouse olfactory bulb.

Effects of noradrenalin and serotonin on cytoplasmic free Ca2+ concentrations ([Ca2+]i) were studied by using the fluorescent indicator fura-2 in cultured local interneurons of mouse olfactory bulb. Application of noradrenalin (0.1-100 microM) caused a rapid and concentration-dependent rise in [Ca2+]i, while isoproterenol was ineffective at concentrations up to 100 microM. The noradrenalin (1 microM)-induced increase in [Ca2+]i was completely inhibited by pretreatment with alpha 1-antagonist, prazosin (100 nM), whereas the inhibitory effect of alpha 2-antagonist, yohimbine, was about 100-times less potent. Serotonin (0.1-100 microM) also caused the dose-dependent rise in [Ca2+]i, which was inhibited by serotonin2 antagonist, ketanserin. Even in the absence of the extracellular calcium, the noradrenalin- or serotonin-induced increase in [Ca2+]i was observed. These results indicate that both noradrenalin and serotonin elicit the rise in [Ca2+]i in local interneurons of the olfactory bulb. They also suggest that the rise in [Ca2+]i is mediated by alpha 1-adrenergic and serotonin2 receptors, and that the increased calcium is mainly derived from intracellular calcium storage sites. The above results provide evidence to suggest that in the olfactory bulb, noradrenergic and serotonergic centrifugal fibers exert modulatory influences on synaptic interactions between mitral/tufted cells and local interneurons by increasing cytoplasmic Ca2+ in local interneurons.

Animals↗
PubMed1992

Distribution of putative odour receptor proteins in olfactory epithelium.

To investigate immunohistochemically the spatial localization of putative odour receptor proteins, we synthesized a polypeptide which corresponds to a region of a putative odour receptor protein, I3, and raised an antibody to the peptide. In rat olfactory epithelium, the antibody specifically recognized cilia of a small subset of olfactory receptor neurons, suggesting that the odour receptor protein is localized selectively in the cilia. Olfactory receptor neurons having immunoreactive cilia were distributed sparsely throughout the epithelium. This suggests that receptor neurons expressing a similar odour receptor protein are probably distributed similarly in the epithelium.

Amino Acid Sequence↗
PubMed1992

Effects of cisapride on gastrointestinal motor activity and gastric emptying of disopyramide.

The effects of cisapride on the gastrointestinal contractile activity and pharmacokinetics of disopyramide were determined in beagle dogs and patients with arrhythmia. In the animal experiments, the gastric motor index was significantly decreased by i.v. administration of disopyramide in a dose-dependent fashion. The peak decrease of the motor index was observed within 5 min after i.v. injection of disopyramide; the motor index then recovered gradually to the level present prior to drug administration. I.v. administration of cisapride (0.5 mg/kg) markedly increased gastrointestinal contractile activity following the decrease induced by disopyramide pretreatment (5 mg/kg, i.v.). In the clinical studies, the gastric emptying test was performed using the acetaminophen method. A significant correlation between plasma concentrations of disopyramide and gastric emptying time has been found (p < 0.001). The combination of disopyramide (100 mg t.i.d.) and cisapride (2.5 mg t.i.d.) significantly increased gastric emptying compared with that induced by disopyramide alone. The peak plasma concentration of disopyramide in association with cisapride oral administration was significantly higher, and the apparent absorption rate constant and lag time of disopyramide were about 2-fold higher and 2-fold shorter, respectively, than for disopyramide alone. Cisapride, acting as a cholinergic agonist, may counteract the anticholinergic effect of disopyramide on gastric motility. As a factor influencing drug absorption, gastric emptying is of importance, as it determines the rate of drug delivery to the small intestine. Therefore, the oral administration of disopyramide with cisapride may be useful for patients with delayed gastric emptying.

Administration, Oral↗
PubMed1991

Molecular cloning of cDNA for the import precursor of human subunit B of H(+)-ATP synthase in mitochondria.

The nucleotide sequence of the import precursor of subunit b of human H(+)-ATP synthase has been determined from a recombinant cDNA clone isolated by screening a human kidney cDNA library with a cDNA for rat subunit b as a probe. The sequence was composed of 1,134 nucleotides including a coding region for the import precursor of subunit b and noncoding regions on the 5'- and 3'-sides. The import precursor of subunit b and its mature polypeptide deduced from the open reading frame were found to consist of 256 and 214 amino acid residues with molecular weights of 28,893 and 24,610, respectively. The presequence of 42 amino acids could be the import signal peptide for directing the protein into the mitochondrial matrix.

Amino Acid Sequence↗