[A SNP in BDNF gene is associated with human memory and BDNF secretion].
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Brain-Derived Neurotrophic Factor↗
Biomedical subjects
Masami Kojima
Publications and source records attributed to Masami Kojima.
Clodronate stimulates osteoblast differentiation in ST2 and MC3T3-E1 cells and rat organ cultures.
We investigated the direct effects of various bisphosphonates on osteoblasts. At 10(-5) M, clodronate increased alkaline phosphatase activity in cultured MC3T3-E1 (osteoblast-like line) and ST2 (pluripotent mesenchymal line) cells. Etidronate significantly increased alkaline phosphatase activity at 10(-5) M only in MC3T3-E1 cells. These effects were due to an increase in alkaline phosphatase-positive cell numbers, and the differentiation-enhanced cells were capable of mineralization (von Kossa stain). Other bisphosphonates (pamidronate, alendronate, and incadronate) did not increase alkaline phosphatase activity in either cell line. In cultured rat calvariae, clodronate stimulated the expression of genes for alkaline phosphatase and osteocalcin (osteoblast-differentiation markers), but decreased the expression of the gene for tartrate-resistant acid phosphatase (osteoclast marker). Clodronate, etidronate, and incadronate inhibited protein Tyr phosphatase and Ser/Thr phosphatase activities in MC3T3-E1 cells. These data suggest that clodronate acts directly on mesenchymal cells to enhance osteoblast differentiation, and this effect may be partly expressed through inhibition of protein Tyr phosphatase and/or Ser/Thr phosphatase activity.
Alkaline Phosphatase↗
Mouse model of airway remodeling: strain differences.
We found that continuous eosinophilic inflammation after repeated antigen instillation into the nose was observed only in A/J mice, not in three other strains. Histologic analysis of tissues from A/J mice revealed features typical of airway remodeling, i.e., airway wall thickening and increased collagen depositions were observed after 12 weeks' antigen exposure. Persistent airway hyperresponsiveness (AHR) was observed in chronically antigen-exposed A/J mice. Eosinophilic inflammation, collagen deposition, and airway wall thickening were all less marked in BALB/c mice than in A/J mice, and no AHR was observed in the former strain. In C57BL/6 and C3H/HeJ mice, eosinophilic inflammation, airway wall thickening, and AHR were not observed at all, although slightly increased collagen deposition was observed. Thus, we found that these changes were strain-dependent. On the other hand, in A/J mice inhalational antigen challenge after ovalbumin/alum immunization led only to a transient increase in eosinophils and to less airway wall thickening, indicating the importance of the protocol used. Use of A/J mice and giving antigen by instillation via the nose is to be recommended for studies of the mechanisms underlying asthma. In particular, useful qualitative and quantitative information relating to the structural and histologic changes in the lungs may be obtainable using this model.
Administration, Intranasal↗
Functional muscarinic cholinoceptors in the isolated canine ureter.
The purpose of present study was to characterize the functional muscarinic cholinoceptor (mAChR) subtypes in the isolated canine ureter. Carbachol (CCh), a non-selective mAChR agonist, concentration-dependently increased the frequency of the rhythmic contractions in isolated spiral ureteral preparations, the pD(2) value being 5.78+/-0.12. We then evaluated the effects of subtype-selective mAChR antagonists on the CCh-induced rhythmic contractions. The rank order of antagonistic potencies (apparent pA(2)) was 4-diphenylacetoxy- N-methylpiperidinemethiodide (4-DAMP; M3-subtype selective; 9.31+/-0.06) >atropine (non-selective; 9.16+/-0.10) >himbacine (M4-subtype selective; 7.32+/-0.18) >pirenzepine (M1-subtype selective; 6.78+/-0.16) >methoctramine (M2-subtype selective; 5.51+/-0.43). In sharp contrast, CCh concentration-dependently reduced the 80 mM KCl-induced contraction in longitudinal ureteral preparations, the pD(2) value being 4.83+/-0.10. On this CCh-induced ureteral relaxation, the rank order of antagonistic potencies (apparent pA(2)) was atropine (8.56+/-0.09) >4-DAMP (7.63+/-0.21) >himbacine (7.46+/-0.09) >methoctramine (6.54+/-0.18) >pirenzepine (6.33+/-0.22). The nitric-oxide-synthase inhibitor N(omega)-nitro-L-arginine (L-NOARG; 1 x 10(-4) M) had no effect on the CCh-induced ureteral relaxation. These data suggest that the CCh-induced rhythmic contraction in the spiral preparation was mediated via the M3-receptor, while the CCh-induced relaxation in the longitudinal preparation was probably mediated mainly via the M4-receptor.
Animals↗
The BDNF val66met polymorphism affects activity-dependent secretion of BDNF and human memory and hippocampal function.
Brain-derived neurotrophic factor (BDNF) modulates hippocampal plasticity and hippocampal-dependent memory in cell models and in animals. We examined the effects of a valine (val) to methionine (met) substitution in the 5' pro-region of the human BDNF protein. In human subjects, the met allele was associated with poorer episodic memory, abnormal hippocampal activation assayed with fMRI, and lower hippocampal n-acetyl aspartate (NAA), assayed with MRI spectroscopy. Neurons transfected with met-BDNF-GFP showed lower depolarization-induced secretion, while constitutive secretion was unchanged. Furthermore, met-BDNF-GFP failed to localize to secretory granules or synapses. These results demonstrate a role for BDNF and its val/met polymorphism in human memory and hippocampal function and suggest val/met exerts these effects by impacting intracellular trafficking and activity-dependent secretion of BDNF.
Alleles↗
A novel type of membrane-associated prostaglandin E synthase.
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Amino Acid Sequence↗
Effects of pilocarpine hydrochloride and cevimeline on submandibular/sublingual salivation in rat xerostomia model produced by X-ray irradiation.
The present study was performed to assess the effects of pilocarpine hydrochloride ((3S,4R)-3-ethyl-dihydro-4-[(1-methyl-1H-imidazole-5-yl)methyl]-2(3H)-furanone monohydrochloride, CAS 54-71-7) and cevimeline ((+/-)-cis-2-methylspiro[1,3-oxathiolane-5,3'-quinuclidine] hydrochloride, hemihydrate, CAS 153504-70-2), muscarinic receptor agonists, on salivary secretion from the submandibular/sublingual (SM/SL) glands in normal rats and in rats with xerostomia induced by X-ray (15 Gy) irradiation. To clarify their pharmacological safety profiles, the two drugs were further compared with regard to subtype selectivity for muscarinic receptors (M1, M2, and M3) and central nervous, respiratory, and cardiovascular effects. Pilocarpine hydrochloride (0.1-0.8 mg/kg i.d.) and cevimeline (3-30 mg/kg i.d.) dose-dependently increased salivary flow rate and total salivary volume in a 120-min period from SM/SL glands in both normal and irradiated rats, the minimum effective doses for their sialagogic effects being 0.2 and 10 mg/kg, respectively. Both drugs also increased protein output from SM/SL glands to a degree that depended on the increase in salivary volume in normal and irradiated rats. In a binding study using radiolabeled antagonists, neither pilocarpine hydrochloride nor cevimeline displayed subtype selectivity for muscarinic receptors, indicating non-selective muscarinic agonism. Effects on the central nervous system (CNS) were assessed by monitoring changes in body temperature in conscious normal rats. Pilocarpine hydrochloride (0.4-4 mg/kg p.o.) had no effect on body temperature, but cevimeline (30 and 100 mg/kg p.o.) caused a significant hypothermia. In terms of respiratory and cardiovascular effects in anesthetized normal rats, there was no clear difference in safety margin between pilocarpine hydrochloride and cevimeline, both drugs inducing significant changes in respiratory rate, heart rate, and blood pressure at doses close to those inducing sialagogic effects. These results suggest that pilocarpine hydrochloride could be used as a sialagogic drug for postirradiation-induced xerostomia with fewer adverse effects on the CNS.
Animals↗
Effect of ozagrel, a selective thromboxane A2-synthetase inhibitor, on cerebral infarction in rats. Comparative study with norphenazone, a free-radical scavenger.
The effects of ozagrel (CAS 82571-53-7), a thromboxane A2-synthetase inhibitor, and norphenazone (CAS 89-25-8), a free-radical scavenger, on cerebral infarction were assessed using the suture-induced middle cerebral artery occlusion (MCAO) model and a microthrombosis model. In the former model, the middle cerebral artery was occluded for 2 h, and the infarction area and volume were evaluated 24 h after the start of reperfusion. In the latter model, microthrombosis were induced by two injections of sodium laurate (interval, 2 days) into the internal carotid artery, and the neurologic deficits were evaluated on the day afer the 2nd injection. Ozagrel at 3 mg/kg decreased both the area and volume of the cortical infarction after ischemia-reperfusion of the middle cerebral artery. Ozagrel also had suppressive effects on the neurologic deficits in the microthrombosis model. Norphenazone at 1 and 3 mg/kg had no clear effects in either model. Since the suture-induced MCAO model and the microthrombosis model are models for occlusion-reperfusion of the major cerebral arteries and lacunar infarction, respectively, these results suggest a highly beneficial effect of ozagrel in the clinical therapy for stroke.
Animals↗
Functional characterization of beta-adrenoceptor subtypes in the canine and rat lower urinary tract.
PURPOSE: We compared the effect of a beta 3-adrenoceptor (AR) agonist with that of beta 1 and beta 2-AR agonists on the urethra and bladder in the dog and rat. MATERIALS AND METHODS: In an in vitro experiment we studied the relaxant effect of subtype selective beta-AR agonists in canine and rat urethral and bladder smooth muscle using an organ bath method. In addition, in urethane anesthetized rats we measured urethral pressure and bladder pressure simultaneously in the presence of the beta 3-agonist CL316243 and the beta 2-agonist procaterol in 4 or 5 animals. RESULTS: In the dog the relaxing effects of isoprenaline in the distal urethra were about half those seen in the detrusor and trigone. The rank order of relaxing potency was CL316243 > dobutamine (beta 1-agonist) = procaterol in detrusor and trigone but procaterol > dobutamine = CL316243 in the prostatic and distal urethra. In rat urethral smooth muscle in vitro the corresponding order was procaterol > CL316243 > dobutamine and the maximal relaxation to each agonist was about half that seen in the bladder. In the anesthetized rat procaterol clearly decreased urethral pressure but CL316243 produced only a slight decrease at its maximal dose, although each agonists clearly reduced bladder pressure. The beta 2-antagonist ICI-118551 counteracted the decrease in urethral and bladder pressure induced by procaterol. CONCLUSIONS: In rats and dogs a selective beta 3-AR agonist can decrease bladder pressure without affecting urethral pressure.
Adrenergic beta-Agonists↗
Comparison between CL-316243- and CGP-12177A-induced relaxations in isolated canine ureter.
We compared the effects of CL-316243, a selective beta(3)-adrenoceptor agonist, and CGP-12177A, a nonconventional partial beta-adrenoceptor agonist, on the KCl-induced contraction in the isolated canine ureter. CL-316243 concentration dependently relaxed the ureteral contraction, the pD(2) value being 7.75 +/- 0.11. This relaxation was competitively antagonized by the selective beta(3)-adrenoceptor antagonist SR58894A and by the nonselective beta-adrenoceptor antagonist bupranolol, their pA(2) values being 7.08 +/- 0.08 and 6.43 +/- 0.09, respectively. CGP-12177A concentration dependently reduced the KCl-induced contraction, the pD(2) value being 6.30 +/- 0.25. Even at 1 x 10(-5) mol/l, CGP-20712A (a selective beta(1)- adrenoceptor antagonist) did not shift the concentration-response curves for CL-316243 or CGP-12177A. SR58894A did not induce a parallel rightward shift in the concentration-response curve for CGP-12177A, but bupranolol did produce such a shift, pA(2) and slope values in the Schild plot being 7.15 +/- 0.77 and 0.60 +/- 0.15, respectively. Hence, the competition characteristics for SR58894A and bupranolol differed between the CL- 316243-induced and CGP-12177A-induced relaxations. Our results suggest that CGP-12177A produces ureteral relaxation in the dog via an atypical beta-adrenoceptor (possibly, an atypical site/state of the beta(3)-adrenoceptor) as well as via the typical beta(3)-adrenoceptor.
Adrenergic beta-Agonists↗
Pharmacological profile of KUL-7211, a selective beta-adrenoceptor agonist, in isolated ureteral smooth muscle.
Since, in the human ureter, both beta(2)- and beta(3)-adrenoceptors mediate adrenergic-stimulation-induced relaxation, selective beta(2)-/beta(3)-adrenoceptor agonists might prove clinically useful for relieving ureteral colic and promoting stone passage. We evaluated the beta-adrenoceptor subtype selectivity and ureteral-relaxing efficacy of (-)-2-[4-(2-[[(1S,2R)-2-hydroxy-2-(4-hydroxyphenyl)-1-methylethyl]amin] ethyl)phenyloxy]acetic acid (KUL-7211), a new beta-adrenoceptor agonist, in vitro. In rat isolated organs, its selectivities, for inhibition of spontaneous uterine contraction (mediated via beta(2)-adrenergic stimulation) and inhibition of colonic contraction (via beta(3)-adrenergic stimulation) versus increase in atrial rate (via beta(1)-adrenergic stimulation), were 56.3 and 242.2, respectively. KUL-7211 relaxed 80-mM-KCl-induced tonic contractions in both rabbit (pD(2) value: 5.86 +/- 0.13, whose ureteral relaxation is mediated via beta(2)-adrenergic stimulation) and canine (pD(2) value: 6.52 +/- 0.16, via beta(3)-adrenergic stimulation) isolated ureters in a concentration-dependent manner. These KUL-7211-induced relaxing effects were antagonized by ICI-118,551 (selective beta(2)-adrenoceptor antagonist, pK(B) value: 8.91 +/- 0.24) in the rabbit ureter and by bupranolol (non-selective beta-adernoceptor antagonist, pK(B) value: 6.85 +/- 0.12) in the canine ureter. KUL-7211 also reduced the spontaneous rhythmic contraction in a canine ureteral spiral preparation in a concentration-dependent manner, the pD(2) value being 6.83 +/- 0.20. These data clearly demonstrate that KUL-7211 selectively stimulates both ureteral beta(2)- and beta(3)-adrenoceptors and potently relaxes ureteral smooth muscle. KUL-7211 may be a novel and useful medication for relieving ureteral colic and promoting stone passage in urolithiasis patients.
Acetates↗
Characteristics of the hemostatic action of KFA-1411, an inhibitor of coagulation factor Xa (FXa), in humans and various animals.
This study examined a low-molecular-weight factor-Xa inhibitor, KFA-1411 (3-[N-(3-amidinophenyl)-N-[N-[4-[1-(1-iminoethyl)piperidin-4- yl]phenyl]carbamoylmethyl]aminomethyl]phenoxyacetic acid monosulfonate-dihydrate). KFA-1411 selectively inhibited FXa among the serine proteases in the human blood-coagulation cascade with a Ki value of 1.73 nM, (selectivity ratio, 15000 versus its action on thrombin). The anticoagulant action of KFA-1411 in human plasma almost equaled that of the selective thrombin inhibitor, argatroban. KFA-1411 did not inhibit platelet aggregation at the concentration at which it showed an anticoagulant action. In contrast, argatroban, heparin, and low-molecular-weight heparin (LMWH; dalteparin) inhibited thrombin-induced platelet aggregation at concentrations lower than those needed for their anticoagulant actions. The FXa-inhibiting action of KFA-1411 differed among animal species, the maximum effect being seen in humans, followed by monkeys and rabbits, with rats and mice showing about one-tenth the potency seen in humans. A species variation was also observed among the values obtained for KFA-1411 in respect of anticoagulant activity in plasma (monkeys again being closest to humans). These results indicate that KFA-1411 may exhibit antithrombotic efficacy without an unwanted platelet-related action in the future treatment of various thrombotic diseases. The experimental model of monkeys is recommended for estimation of the clinical effects and safety of KFA-1411 in humans.
Animals↗
Brain-derived neurotrophic factor promotes interaction of the Nck2 adaptor protein with the TrkB tyrosine kinase receptor.
Brain-derived neurotrophic factor (BDNF) binds to and activates the TrkB tyrosine kinase receptor to regulate cell differentiation, survival, and neural plasticity in the nervous system. However, the identities of the downstream signaling proteins involved in this process remain unclear. Using a yeast two-hybrid screen with the intracellular domain (ICD-TrkB) of the TrkB BDNF receptor, we identified the Nck2 adaptor protein as a novel interaction partner of the active form of TrkB. Additionally, we identified three tyrosines in ICD-TrkB (Y694, Y695, and Y771) that are crucial for this interaction. Similar results were obtained for Nck1, an Nck2 homolog. We also found that TrkB could be co-precipitated with GST-Nck2 recombinant protein or anti-Nck antibody in BDNF-activated cortical neurons. These results suggest that BDNF stimulation promotes interaction of Ncks with TrkB in cortical neurons.
Amino Acid Sequence↗
Identification and characterization of a novel type of membrane-associated prostaglandin E synthase.
Membrane-associated prostaglandin E synthase (mPGE synthase) was previously purified to apparent homogeneity from the microsomal fraction of bovine heart (Watanabe, K., et al., Biochim. Biophys. Acta 1439, 406--414, 1999). The N-terminal 22-amino acid sequence of the purified enzyme was identical to that of the 88th to 109th amino acids deduced from the monkey (AB046026) or human (AK024100) cDNA that encodes a hypothetical protein with unknown function. The primary structure has the consensus region of glutaredoxin and of thioredoxin. We constructed an expression plasmid, using the vector (pTrc-HisA) and the monkey cDNA for the 290-amino-acid polypeptide. The recombinant protein with a M(r) of 33 kDa exhibited PGE synthase activity and was purified to apparent homogeneity by nickel-chelating column chromatography. The V(max) and K(m) values for PGH(2) of the purified recombinant mPGE synthase were about 3.3 mumol/min center dot mg of protein and 28 muM, respectively. The recombinant enzyme was activated by various SH-reducing reagents, i.e., dithiothreitol, glutathione (GSH), and beta-mercaptoethanol, in order of decreasing effectiveness. Moreover, the mRNA distribution was high in the heart and brain, but the mRNA was not expressed in the seminal vesicles. These results indicate that the recombinant mPGE synthase is identical to the enzyme purified from the microsomal fraction of bovine heart, and is a novel type of mPGE synthase based on the primary structure, a broad specificity of thiol requirement, and tissue distribution.
Amino Acid Sequence↗
Modification of ureteral motility and promotion of urine flow around an intraureteral obstruction by CL-316243, phenylephrine, and furosemide in dogs.
The aim of this study was to evaluate the effects of a beta3-adrenoceptor (AR) agonist (CL-316243), an alpha1-AR agonist (phenylephrine), and a loop diuretic (furosemide) on the spontaneous rhythmic contractions of the isolated canine ureter and on an acute ureteral obstruction produced by inflation of a balloon catheter in anesthetized dogs. In the isolated ureter, CL-316243 concentration dependently reduced both the amplitude and frequency of the rhythmic contractions (pD(2): 7.19 +/- 0.33), whereas phenylephrine significantly enhanced both variables (pD(2): 5.26 +/- 0.09) and furosemide reduced them only slightly. In the acute ureteral obstruction model, the intraureteral pressure (IUP) gradually rose to reach a plateau of 58.9 mm Hg after inflation of a balloon catheter within the lower ureter. Intravenous administration of CL-316243 (0.3 microg/kg) significantly reduced the elevated IUP and the resumed urine flow (UF), leading to a sustained reduction in the IUP. In contrast, the IUP continued to increase above the plateau level for 10 minutes after phenylephrine administration (10 microg/kg) and for 30 minutes after furosemide administration (1,000 microg/kg). In the phenylephrine group, the UF resumed when the IUP reached 75.8 mm Hg, and thereafter the IUP gradually decreased in parallel with the increase in the UF. From these results, we conclude that in dogs, CL-316243 reduces the IUP by allowing the UF to resume as a result of a relaxation of ureter at the obstruction site, whereas with phenylephrine, the reduction in the IUP is secondary to a resumption in the UF resulting from an induced contraction of ureter that causes an increase in hydrostatic pressure above the obstruction site.
Adrenergic alpha-Agonists↗
Pre- and post-synaptic modification by neurotrophins.
Since the discovery of nerve growth factor, there has been accumulating evidence that neurotrophins (NTs) mediate various biological responses of peripheral and central neurons. NTs have been traditionally studied as the regulating factors of neuronal survival and differentiation. Recent data indicate that NTs can modify neuronal plasticity by specific changes in pre- and post-synaptic functions. Whether the NT action is pre- or post-synaptic, however, remains to be controversy. Here we review the recent advances of NTs involved in synaptic plasticity, as well as the pre- and post-synaptic arguments. We also review the recent discovery that proneurotrophins and mature NTs have the differential ability to bind selective receptors and mediate distinctive biological actions.
Animals↗
Study of the insulinotropic effect of the novel antihyperglycemic agent KAD-1229 using HIT T15 cells, a hamster's insulinoma cell line.
The insulinotropic effect of (+)-monocalcium bis [(2S)-2-benzyl-3-(cis-hexahydro-2-isoindolinyl-carbonyl)propionate] dihydrate (CAS 145375-43-5, KAD-1229) was assessed by comparing it with those of glibenclamide (CAS 10238-21-8), nateglinide (CAS 105816-04-4), and repaglinide (CAS 135062-02-1) using HIT T15 cells, a hamster insulinoma cell line. Although their potencies were different, KAD-1229, glibenclamide, nateglinide, and repaglinide all concentration-dependently and significantly induced insulin release from these cells. Further, each agent displaced the binding of 3H-glibenclamide to the cell membrane and inhibited 86Rb+ efflux from the cells. These results indicate that KAD-1229, glibenclamide, nateglinide, and repaglinide each exert their insulinotropic effect by binding to the glibenclamide binding sites (sulfonylurea receptors) on pancreatic beta-cells and closing K+ channels. Diazoxide, a K+ channel opener, and nitrendipine, a Ca2+ blocker, suppressed the insulin release induced by KAD-1229 or glibenclamide. These results demonstrate that the insulinotropic actions of KAD-1229 and glibenclamide involve similar underlying pathways.
Animals↗
Diversity of inhibitory responses to beta2-stimulants shown by term-pregnant human myometria in vitro is partly due to differences in receptor density.
OBJECTIVE: The aims of this study were (1) to evaluate the usefulness of the new beta2-adrenergic stimulant KUR-1246 as a tocolytic agent and (2) to clarify the mechanisms that underlie the diverse inhibitory effects of beta2-stimulants that are seen in human myometria in vitro. STUDY DESIGN: The displacement of tritiated ([3H]) (-)CGP 12177 (0.4 nmol/L) by KUR-1246 and other beta2-stimulants was examined with human beta(1)- and beta2-receptors present on membrane fractions. The inhibitory effects of these beta2-stimulants on the term-pregnant human myometrium were compared with the use of isometric tension recording and microelectrode methods. Finally, the relationship between [3H]dihydroaloprenolol binding and the magnitude of the tocolytic effect of isoproterenol was examined. RESULTS: KUR-1246 was approximately 80 times and 7 times more selective for beta2-receptors than isoproterenol and ritodrine, respectively. The inhibitory effect of KUR-1246 was as strong as the inhibitory effect of the conventional beta2-adrenergic stimulants. A wide range of inhibitory effects was observed, even when high concentrations of isoproterenol or KUR-1246 were applied. There was a correlation between the degree to which isoproterenol suppressed contractions and the number of [3H]dihydroaloprenolol binding sites on the membrane in each muscle strip. CONCLUSION: KUR-1246 should be a very useful beta2-adrenergic stimulant for use as a tocolytic agent because of its high selectivity for the beta2-receptor and its potent inhibitory effect. The diversity of the inhibitory effects that are induced by beta2-stimulants is at least partly due to differences in beta2-receptor density among term-pregnant human myometria.
Acetamides↗