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T Ohrui

Publications and source records attributed to T Ohrui.

At least 55 records · Page 3Linked to original sources
PubMed1996

Effects of adrenomedullin and calcitonin gene-related peptide on airway and pulmonary vascular smooth muscle in guinea-pigs.

1. The airway and pulmonary vascular effects of adrenomedullin were studied in the guinea-pig isolated trachea, main bronchi and pulmonary artery in vitro and compared to the effects of calcitonin gene-related peptide (CGRP). 2. In tracheal rings, CGRP (1 nM to 1 microM) potentiated the cholinergic contractions induced by electrical field stimulation (EFS) at 5 Hz in a concentration-dependent manner. At a concentration of 1 microM, CGRP slightly decreased the responses to log EFS frequency, producing 50% of the maximum contraction from a control value of 0.77 +/- 0.10 Hz to 0.54 +/- 0.05 Hz without a significant effect on the concentration-response curves to acetylcholine (ACh). In contrast, adrenomedullin (1 nM to 1 microM) did not alter either EFS-induced cholinergic or ACh-induced contractions. 3. In bronchial strips, CGRP (1 nM to 1 microM) slightly reduced both the non-adrenergic non-cholinergic (NANC) contraction induced by EFS at 10 Hz and the substance P (1 microM)-induced contraction in a concentration-dependent manner, whereas adrenomedullin (1 nM to 1 microM) was without effect. 4. Neither CGRP (1 microM) nor adrenomedullin (1 microM) altered NANC relaxation induced by EFS at 5 Hz in tracheal rings precontracted with histamine (10 microM). 5. Adrenomedullin (1 nM to 1 microM) and CGRP (1 nM to 1 microM) induced a concentration-dependent relaxation of the histamine (10 microM)- and prostaglandin F2 alpha (10 microM)-precontracted pulmonary arterial rings with intact endothelium with a similar potency. 6. Neither removal of the endothelium nor NG-nitro-L-arginine methyl ester (100 microM) altered the vasorelaxant effects of adrenomedullin (1 nM to 1 microM) and CGRP (1 nM to 1 microM). 7. The putative CGRP receptor antagonist, CGRP8-37 (1 microM to 10 microM) concentration-dependently attenuated the CGRP (3 nM to 30 nM)-induced vasorelaxant actions, whereas it had no effect on the relaxation of vessel rings induced by adrenomedullin (3 nM to 30 nM). 8. These results suggest that adrenomedullin is a potent vasodilator of the pulmonary artery without any bronchomotor effect in the guinea-pig lung, and that the vasorelaxant actions of adrenomedullin are not mediated via the activation of CGRP1 receptors.

Adrenomedullin↗
PubMed1996

P2u-purinoceptor regulation of chloride secretion in cultured human tracheal submucosal glands.

We examined the purinergic regulation of chloride secretion and intracellular calcium ion concentration ([Ca2+]i) in the cultured epithelial cells passaged from human tracheal submucosal glands. Adenosine, AMP, ADP, ATP, and UTP induced transient short-circuit current (Isc) responses in a concentration-dependent fashion. The rank order of peak Isc responses at 10 microM concentrations was UTP = ATP > ADP > AMP = adenosine. Diphenylamine-2-carboxylic acid (1 mM) and 4,4'- diisothiocyano-2,2'-stilbene disulfonate (0.5 mM), and quinidine (1 mM) inhibited Isc responses induced by extracellular nucleotides. However, amiloride (10 microM) was without effect. Theophylline (1 mM) did not alter ATP (10 microM)-induced Isc response. Increases in Isc induced by ATP and UTP were significantly larger than those by alpha, beta-methylene ATP, beta, gamma-methylene ATP, or 2-methylthio ATP. Extracellular nucleotides caused increases in [Ca2+]i, and the rank order of [Ca2+]i responses was same as that of Isc responses. 1,2-Bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxy-methyl ester (50 microM) inhibited increases in Isc and [Ca2+]i induced by extracellular nucleotides. These results suggest that extracellular nucleotides induce chloride secretion across cultured human tracheal glands via a P2u-purinoceptor, and this chloride secretion appears to be dependent on increases in [Ca2+]i and activation of Ca-dependent K channels.

Adenosine Triphosphate↗
PubMed1996

Angiotensin-converting enzyme inhibitor and danazol increase sensitivity of cough reflex in female guinea pigs.

To examine the mechanisms of an angiotensin-converting enzyme (ACE) inhibitor-induced cough in perimenopausal and postmenopausal women, cough responses to aerosols of capsaicin and citric acid were examined in four groups of female guinea pigs treated orally with danazol (D) (an agent decreasing plasma estrogen levels), cilazapril (C) (an inhibitor of ACE), both danazol and cilazapril (C+D), or without either drug (control group) for 4 to 5 wk. Capsaicin caused dose-dependent increases in the number of coughs in all four groups. C or D alone shifted dose-response curves to capsaicin (from 10(-7) M to 10(-3) M) to lower concentrations compared with the control, and C+D further shifted them. Likewise, the number of coughs induced by citric acid (3 x 10(-1) M; 2 min) was highest in animals treated with C+D and significantly higher in animals treated with C or D than in the control group. Aerosols of a selective substance P (SP) receptor antagonist FK 888 (10(-5) M; 2 min) inhibited capsaicin-induced cough in all four groups, and dose-response curves to capsaicin did not differ significantly at any concentrations among the four groups in the presence of FK 888 (p > 0.10). D decreased cyclic AMP levels in the trachea, irrespective of the combination of C. A beta 2-adrenoceptor agonist, procaterol, which is thought to inhibit SP release by elevation of cyclic AMP in sensory nerves, dose-dependently inhibited the number of coughs induced by capsaicin (10(-3) M) in animals treated with D. The present study suggests that SP is a common mechanism mediating increases in the sensitivity of cough reflex induced by both ACE inhibition and a decrease in plasma estrogen levels, and the additive effects of the two events may explain the high incidence of cough during ACE inhibitor therapy in perimenopausal and postmenopausal women.

Adrenergic beta-Agonists↗
PubMed1996

Role of Leukotriene-degrading enzymes in pulmonary response to antigen infusion in sensitized guinea pigs in vivo.

To determine the role of leukotriene (LT)-degrading enzymes in allergic reactions, we studied the effects of inhibitors of gamma-glutamyl transpeptidase (gamma-GTP) and dipeptidases on increases in pulmonary insufflation pressure (PIP) and vascular permeability induced by ovalbumin (OA) antigen in guinea pigs sensitized to OA antigen in vivo. Vascular permeability was assessed by the amount of extravasated Evans blue dye from the trachea, main bronchi, and segmental bronchi. An intravenous (i.v.) administration of OA antigen (200 micrograms/kg) caused increases in PIP and extravasated Evans blue dye, and OA antigen-induced effects were potentiated by gamma-GTP inhibitor L-serine borate (3 x 10(-5) M/kg, i.v.) (P < 0.05) and an inhibitor of dipeptidases, L-cysteine (3 x 10(-5) M/kg, i.v.) (P < 0.01). OA antigen-induced increases in PIP and Evans blue dye extravasation were in part inhibited by LT-receptor antagonist ONO-1078 (10(-4) M/kg, i.v.). Guinea-pig tracheal tissues contained gamma-GTP and microsomal dipeptidase activities. Histochemical and immunohistochemical studies indicate that gamma-GTP-like activity existed in the epithelium and smooth muscle, and an activity of microsomal dipeptidase was observed in the endothelial cells of microvessels and epithelium. These results suggest that LT-degrading enzymes have an important role in regulating allergic reaction in the airway in vivo.

Animals↗
PubMed1996

[Rhinovirus infection and expression of adhesion molecules in human tracheal epithelium].

Rhinovirus infection has attracted attention because it can lead to acute exacerbations of chronic inflammatory airway diseases such as bronchial asthma and chronic bronchitis. We established a culture system and inoculated human rhinovirus to human tracheal epithelial cells, and found that infection was augmented by up-regulation of intercellular adhesion molecule-1, which is the receptor for this virus. We also found that human airway epithelial cells infected with rhinovirus were susceptible to a chemical oxidant (H2O2) released by inflammatory cells, which would contribute to acute exacerbations of inflammatory airway diseases. Finally, we found that anti-ICAM-1 antibodies or dexamethasone can inhibit the infectivity to rhinovirus by suppressing ICAM-1, and diminish susceptibility to oxidants in the cultured human tracheal epithelium.

Anti-Inflammatory Agents↗
PubMed1995

The role of carbon monoxide in lucigenin-dependent chemiluminescence of rat alveolar macrophages.

We have investigated the role of carbon monoxide (CO) in lucigenin-dependent chemiluminescence of alveolar macrophages from rat lungs. CO (10 nM to 1 microM) decreased chemiluminescence of alveolar macrophages in a concentration-dependent fashion. At a concentration of 1 microM, CO significantly increased intracellular cyclic GMP levels from a control value of 175 +/- 25 fmol/2 x 10(6) cells to 431 +/- 49 fmol/2 x 10(6) cells. Pretreatment of alveolar macrophages with NG-monomethyl-L-arginine (100 microM) failed to inhibit CO (1 microM)-induced decreases in chemiluminescence of alveolar macrophages (3.7 +/- 0.7 cpm x 10(3) in the presence of NG-monomethyl-L-arginine and 3.4 +/- 0.6 cpm x 10(3) in the absence of NG-monomethyl-L-arginine) and CO (1 microM)-induced increases in intracellular cyclic GMP levels (452 +/- 65 fmol/2 x 10(6) cells in the presence of NG-monomethyl-L-arginine and 419 +/- 58 fmol/2 x 10(6) cells in the absence of NG-monomethyl-L-arginine). Decreases in chemiluminescence of alveolar macrophages induced by CO (1 microM) were concentration-dependently inhibited by methylene blue (from 0.1 microM to 10 microM). Dibutyryl cyclic GMP (db cyclic GMP) (1 mM) also reduced chemiluminescence of alveolar macrophages (1.5 +/- 0.3 cpm x 10(3) in the presence of db cyclic GMP and 3.6 +/- 0.6 cpm x 10(3) in the absence of db cyclic GMP). In contrast to CO and db cyclic GMP, zinc protoporphyrin-9 (10nM to microM), an inhibitor of heme oxygenase potentiated chemiluminescence of alveolar macrophages in a concentration-dependent fashion.(ABSTRACT TRUNCATED AT 250 WORDS)

Acridines↗
PubMed1995

Cytoplasmic motility reflects phagocytic activity in alveolar macrophages from dog lungs.

To determine whether cytoplasmic motility relates to phagocytic activity of alveolar macrophages (AM), we measured the remanent field strength (RFS) from the AM containing Fe3O4 particles (5 x 10(6) cells) and the number of phagocytized fluorescent latex spheres in the AM without having Fe3O4 particles (10(6) cells) harvested by broncho-alveolar lavage from dog lungs in vitro. Cytoplasmic motility was estimated from the relaxation rate (lambda o; min-1) calculated from the decay curve of RFS and the number of phagocytized latex spheres was counted using fluorescent microscopy after the addition of latex spheres (5 x 10(7)). The tumor necrosis factor increased both lambda o and the number of phagocytized latex spheres, and cytochalasin D and colchicine decreased them in a concentration-dependent fashion. Increases and decreases in lambda o induced by drugs paralleled the number of phagocytized latex spheres. These results suggest that cytoplasmic motility reflects phagocytic activity of AM and both cytoplasmic movement and phagocytosis may be regulated by a similar mechanism in the cytoskeletal system.

Animals↗
PubMed1995

A method for measuring Cl efflux from dispersed cells of airway epithelium.

This paper describes a method for measuring the increase in halide permeability of isolated airway epithelial cells induced by adenosine 3',5'-cyclic monophosphate (cAMP). Suspensions of isolated cells, known to contain the cystic fibrosis transmembrane conductance regulator (CFTR), were placed in the upper part of a Swinnex filter holder containing a filter with pores of 0.65 micron diameter. Medium was perfused over the cells at room temperature and collected at minute intervals following its passage through the filter. Experiments were performed on Calu-3 and T84 cells (human lung and colonic epithelial cell lines), primary cultures of dog and human tracheal epithelium, and Swiss 3T3 fibroblasts stably transfected with CFTR. In all cell types, addition of agents that elevate cAMP led to increases in the rates of loss of 36Cl and 125I. However, in human tracheal epithelial cells, warming the medium from room temperature to 37 degrees C was a more effective way of stimulating tracer efflux. Increases in efflux in response to either temperature or cAMP-elevating agents were inhibited by diphenylamine-2-carboxylate, a blocker of CFTR. Reproducible increases in tracer efflux were seen with as few as 10(6) cells. Cells that had been trypsinized off their culture dishes responded better than cells that had been scraped off, although treatment of scraped cells with trypsin enhanced their responsiveness to cAMP-elevating agents. Cystic fibrosis is characterized by the lack of a cAMP-activated Cl conductance in the apical membrane of airway epithlia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

The role of HMT (histamine N-methyltransferase) in airways: a review.

Histamine N-methyltransferase (HMT) expressed in the epithelial and endothelial cells of the airways is a principal enzyme degrading histamine in the body. This brief review summarizes the recent advances in molecular biology related to the pathophysiological role of HMT in regulating airway functions.

Animals↗
PubMed1994

Radiotracer studies of cystic fibrosis transmembrane conductance regulator expressed in Xenopus oocytes.

We measured fluxes of radiotracers in Xenopus oocytes expressing the cystic fibrosis transmembrane conductance regulator (CFTR). Addition of adenosine 3',5'-cyclic monophosphate (cAMP)-elevating agents [forskolin and 3-isobutyl-1-methylxanthine (I/F)] led to large increases in uptake of 36Cl, 125I, and 82Br into oocytes expressing wild-type CFTR or delta F508 CFTR but not sham-injected oocytes. I/F also stimulated halide efflux from CFTR and delta F508 oocytes in the sequence Cl > Br > I. cAMP-induced increases in 36Cl efflux from delta F508 oocytes were approximately 20% of those in CFTR oocytes. Increases in halide efflux were blocked by diphenylamine-2-carboxylic acid but not by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid. The phorbol ester, phorbol 12-myristate 13-acetate, also stimulated 36Cl efflux from CFTR oocytes. ATP uptakes into CFTR and sham oocytes were similar, and both were reduced by I/F. However, ATP uptake into I/F-treated CFTR oocytes was slightly greater (approximately 40%) than into I/F-treated sham oocytes. Urea uptake into CFTR and sham oocytes was similar and in both cases was increased by I/F. However, the I/F-induced increase in urea uptake into CFTR oocytes was significantly greater than for sham oocytes. I/F stimulated formate uptake into CFTR oocytes but not into sham oocytes. Fluxes of 22Na, 86Rb, 35SO4, 32PO4, and mannitol were unaltered by expression and activation of CFTR.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1994

Accumulation of basophils and their chemotactic activity in the airways during natural airway narrowing in asthmatic individuals.

To investigate cellular differentials in natural airway narrowing of steroid-dependent asthmatic individuals, we performed bronchoalveolar lavage (BAL) on 10 inpatients with asthma treated only with bronchodilators during episodes of natural airway narrowing evaluated by serial monitoring of peak expiratory flow (PEF), and on nine normal volunteers. We confirmed that the airway narrowing was not completely reversed by salbutamol aerosol just before the BAL study, but was completely reversed by administration of systemic steroid after the BAL study. Thus, the natural airway narrowing investigated in this study consisted not only of the constriction of airway smooth muscle, but also of edema of the airway mucosa and/or secretion in airways. Both the numbers and percentages of eosinophils and alcian blue-positive cells in BAL fluids from the asthmatic subjects were significantly higher than those of normals, but the numbers and percentages of neutrophils, lymphocytes, and macrophages were not. Thus, eosinophils and alcian blue-positive cells selectively increased in the airways during the natural airway narrowing. Because we found that the metachromatic cells consisted of two types, with a single nucleus and with segmented nuclei, we further examined basophil chemotactic activity (BCA) in BAL fluids. We showed that BCA was significantly higher in the asthmatic (79.3 +/- 17.2 cells/5 hpf) than in the normal subjects (6.2 +/- 1.6 cells/5 hpf), and also that the activity was more strongly correlated with the cells having segmented nuclei (p = 0.95) than with all of the cells (p = 0.73).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

CFTR expression and chloride secretion in polarized immortal human bronchial epithelial cells.

A major limitation in the study of vectorial ion transport, secretion, and differentiated function in the human airway epithelium has been the lack of suitable cell culture systems. Progress in this direction has been made through the transformation of primary cultured epithelial cells. However, these transformants tend to lose differentiated properties with increasing serial passage, particularly following crisis. The successful establishment of a postcrisis SV40 large T-antigen transformed epithelial cell line derived from human bronchial epithelium is described. This cell line, 16HBE14o-, retains differentiated epithelial morphology and functions. Cell cultures show the presence of tight junctions and cilia, and monolayers generate transepithelial resistance, as measured in Ussing chambers, and retain beta-adrenergic stimulation of cAMP-dependent chloride ion transport, measured either by 36Cl- efflux or as short-circuit current in Ussing chambers. The cells also increase chloride transport in response to bradykinin or calcium ionophore. In addition, 16HBE14o- cells express levels of both the cystic fibrosis transmembrane conductance regulator (CFTR) mRNA and protein readily detectable by Northern and Western hybridization analysis, respectively. These cells provide a valuable resource for studying the modulation of CFTR and its role in regulation of chloride ion transport in human airway epithelium as well as other aspects of human airway cell biology.

Bronchi↗
PubMed1994

Quinine inhibits production of tumor necrosis factor-alpha from human alveolar macrophages.

Although tumor necrosis factor-alpha (TNF-alpha) produced by alveolar macrophages plays a key role in acute and chronic inflammatory states of the lung, the regulation of TNF-alpha synthesis remains to be elucidated. Recently, a K channel blocker, quinine, has been reported to inhibit cell proliferation and protein synthesis in lymphocytes, implicating physiologic roles for K channels in lymphocytes. The effect of quinine on protein synthesis in human alveolar macrophages, however, has not been determined, although alveolar macrophages have been reported to have two types of K channels. Therefore, we investigated the effect of quinine on TNF-alpha production from human alveolar macrophages. The production of TNF-alpha was induced by lipopolysaccharide (LPS) stimulation. We obtained the following results. First, LPS induced time-dependent activation of both types of K channels. Second, quinine inhibited TNF-alpha release in a dose-dependent fashion at concentrations of 50 to 200 microM, concentrations capable of blocking both types of K channels, with no appreciable reduction of phagocytosis of latex beads. Third, the compound remarkably inhibited the expression of TNF-alpha mRNA without any appreciable effect on the expression of beta-actin mRNA. These results indicate that both types of K channels are activated by stimulation with LPS and that quinine, at concentrations required to inhibit K channels, specifically blocks TNF-alpha production of human alveolar macrophages at the level of gene transcription.

Adult↗
PubMed1993

Peripheral airway hyperresponsiveness in the choline-deficiently fed rat.

Rats fed with choline-deficient diets are known as a model of aging and learning impairments due to acetylcholine (ACh) deficiency in the brain which may be associated with a decrease in acetylcholinesterase (AChE; EC 3.1.1.7). To determine the role of AChE in bronchial responsiveness, we examined the contractile response of isolated lung parenchymal strips to ACh in control rats and rats fed with choline-deficient diets. Concentration-response curves to ACh shifted to the lower concentrations and the maximum response to ACh was greater in rats fed with choline-deficient diets than in control rats (P < 0.01). Physostigmine (10(-6) M) mimicked effects of choline-deficient diets on the contractile response to ACh. However, concentration response curves to carbachol and 5-hydroxytryptamine did not differ between control rats and rats fed with choline-deficient diets. Choline-deficient diets significantly decreased the AChE activity from homogenates of lung parenchymal tissues (P < 0.01). These results suggest that a decrease in AChE activity of lung tissues may relate to airway hyperresponsiveness to ACh.

Acetylcholine↗
PubMed1993

Calcium-dependent chloride secretion across cultures of human tracheal surface epithelium and glands.

Surface epithelium and gland cells from human trachea were cultured on porous-bottom inserts and loaded with fura 2 to permit measurement of the intracellular calcium concentration ([Ca2+]i). Short-circuit current (Isc), an index of transepithelial active ion transport, was measured on cells from the same cultures. Surface epithelial [Ca2+]i of 82 +/- 15 nM was increased transiently by isoproterenol, histamine, and bradykinin with maximal increases of 88 +/- 17, 480 +/- 149, and 978 +/- 214 nM (n = 15), respectively. Baseline [Ca2+]i in cultured gland cells of 68 +/- 11 nM was increased transiently by isoproterenol, histamine, methacholine, and bradykinin with maximal increases of 105 +/- 19, 233 +/- 47, 327 +/- 121, and 634 +/- 151 nM (n = 17-21), respectively. In both cell types, mediators that increased [Ca2+]i also increased Isc with a time course identical to the increase in [Ca2+]i. Pretreatment with the calcium chelator, 1,2-bis-(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid, acetoxymethyl ester (BAPTA-AM), had no effect on basal Isc or transepithelial resistance but markedly inhibited both the Isc and [Ca2+]i responses to agonists. Forskolin (10(-5) M), 3-isobutyl-1-methylxanthine (10(-3) M), dibutyryl adenosine 3',5'-cyclic monophosphate (10(-3) M), and 8-(4-chlorophenylthio)-cAMP (10(-3) M) had no or only trivial effects on Isc and [Ca2+]i. We suggest that mediators increase Isc across human airway epithelium by activating Ca-dependent basolateral K channels, resulting in hyperpolarization and an increased driving force for Cl exit through apical membrane Cl channels.

Calcium↗