Biomedical subjects

K Tasaka

Publications and source records attributed to K Tasaka.

At least 19 recordsLinked to original sources

PubMed1995

Mouse growth hormone-releasing factor secretion is activated by inhibin and inhibited by activin in placenta.

We investigated the effects of activin and inhibin on the regulation of mouse growth hormone-releasing factor (mGHRF) secretion by primary placental cells harvested at Day 12 of pregnancy. Activin-A, an activator of FSH secretion, inhibited mGHRF secretion. In contrast, inhibin, an inhibitor of FSH secretion, activated mGHRF secretion. The lowest concentrations of activin-A and inhibin that significantly affected mGHRF secretion were 2 nM. Follistatin, a binding protein of activin, completely eliminated the ability of activin to inhibit mGHRF secretion. The steady-state level of mGHRF mRNA, as assessed by Northern analysis, was reduced by incubation of placental cells with activin-A. All activin and inhibin subunit mRNAs were expressed in mouse placenta, and their expressions increased during gestation. These findings suggest that activin and inhibin have opposite effects on mGHRF secretion as compared with FSH secretion and that they regulate mGHRF secretion in an autocrine or paracrine manner in the mouse placenta in vivo.

Activins↗

PubMed1995

Expression of messenger ribonucleic acid for epidermal growth factor (EGF), transforming growth factor-alpha (TGF alpha), and EGF receptor in human amnion cells: possible role of TGF alpha in prostaglandin E2 synthesis and cell proliferation.

The amnion plays important structural and functional roles in the maintenance of pregnancy and the initiation of parturition. Recently, we reported that epidermal growth factor (EGF) activates prostaglandin (PG) production and cell growth in cultured amnion cells. In this study, we showed the expression of EGF, transforming growth factor-alpha (TGF alpha), and EGF receptor protein and messenger ribonucleic acid in amnion cells, using an immunofluorescence technique and the reverse transcription-polymerase chain reaction. Next, we studied the effect of TGF alpha on intracellular Ca2+ mobilization and PGE2 production in amnion cells. TGF alpha induced an increase in the intracellular Ca2+ concentration in amnion cells, and this increase was significantly reduced when the cells were incubated with cobalt chloride (a Ca2+ channel blocker; 2.5 mmol/L) or EGTA (a Ca2+ chelator; 5 mmol/L). TGF alpha enhanced PGE2 production, and this increase was significantly inhibited when the cells were incubated with indomethacin (a cyclooxygenase inhibitor; 10 mumol/L), cobalt chloride (2.5 mmol/L), or EGTA (5 mmol/L). We also investigated the effect of TGF alpha on the growth of cultured human amnion cells by using flow cytometric analysis of the DNA content. TGF alpha induced DNA synthesis by human amnion cells, and indomethacin inhibited the TGF alpha-induced DNA synthesis. These results suggest that 1) EGF/TGF alpha are expressed and produced in amnion cells; 2) these endogenous factors may regulate the proliferation of amnion cells in an autocrine or paracrine manner; and 3) these growth factors may exert their effects via intracellular Ca2+ mobilization and PGE2 production.

Amnion↗

PubMed1995

Scanning electron microscope assessment of exocytotic changes in purified gonadotropes.

These studies were undertaken to characterize the exocytotic changes in purified gonadotropes by three-dimensional imaging using scanning electron microscopy. Rat gonadotropes were purified using a fluorescence-activated cell sorter and an argon laser treatment system. The purified gonadotropes were stimulated with GnRH under various conditions and fixed for scanning electron microscopy. After the GnRH stimulation, many 'hole' structures (diameter 0.1-0.5 micron) were observed on the cell surface, and notably the population of cells with 10 or more holes was clearly increased. The pattern of the time-course of the changes in this population was perfectly consistent with the LH secretory profile of pituitary cells, and their formation of the cells with 10 or more holes was completely inhibited by pretreatment with a GnRH antagonist. Our data suggest that the hole structure represents an exocytotic opening site and that regulated exocytosis in purified gonadotropes can be evaluated by scanning electron microscopy. This method may be widely applicable to other endocrine cells.

Animals↗

PubMed1995

Activin inhibits but inhibin activates mouse placental lactogen-II secretion.

The regulation of mouse placental lactogen (mPL)-I and mPL-II secretion by activin and inhibin and the expression of activin and inhibin subunit mRNAs in the mouse decidua were examined. Activin-A at a concentration of 10 nM/l significantly inhibited mPL-II secretion by placental cells from days 9 and 12 of pregnancy. However, activin-A did not affect mPL-I secretion by cells from days 7 and 9 of pregnancy nor mPL-II secretion by cells from day 7 of pregnancy. By contrast, 10 nM/l inhibin activated mPL-II secretion by cells from day 12 of pregnancy. These effects of activin and inhibin on mPL-II secretion were dose-dependent. Follistatin, which binds to activin and blocks its bioactivity, completely eliminated the inhibitory effect of activin on mPL-II secretion. Incubation of placental cells from day 12 of pregnancy with activin-A resulted in a significant reduction of the mPL-II mRNA level assessed by Northern blot analysis. Northern blot analysis using poly(A)+RNA extracted from the decidua indicated that mouse decidua, as well as the placenta, express all activin and inhibin subunits and that their gene expressions increased during gestation. The expression of these mRNAs in the decidua was much higher than those in the placenta. These findings suggest that activin and inhibin regulate mPL-II secretion and suggest the presence of an autocrine or paracrine regulation of mPL-II secretion in mouse placenta by activin and inhibin after mid-pregnancy in vivo.

Activins↗

PubMed1994

Implantation and growth of epidermal growth factor (EGF) receptor expressing human ovarian cancer xenografts in nude mice is dependent on EGF.

BACKGROUND: The importance of epidermal growth factor (EGF) receptor-dependent growth has not been clarified for in vivo growth of primary human ovarian cancers. METHODS: Seventeen primary human ovarian cancer tissue samples were examined for the presence of EGF receptors by a 125I-EGF-binding study. Three groups of mice were inoculated with EGF receptor expressing and not-expressing cancer tissues. The groups were as follows: control group, Sx group (mice that underwent sialoadenectomy; EGF depleted mice), and Sx+EGF (EGF-replaced) group. The ability of the inoculated tissues to implant and grow then was studied. RESULTS: Of the 17 primary ovarian cancers, 12 expressed EGF receptors and 5 did not. Eight of 12 EGF-receptor expressing cancer tissues implanted and formed growing tumors in control animals. None implanted in the Sx animals. Epidermal growth factor receptor-expressing cancers implanted in Sx animals that received EGF administration. Two of five EGF receptor-negative ovarian cancers implanted and grew in both control and Sx animals. CONCLUSION: Growth of EGF receptor-expressing primary human ovarian cancers may be dependent on EGF in vivo.

Animals↗

PubMed1994

Characterization of activin A-, activin AB- and activin B-responding cells by their responses to hypothalamic releasing hormones.

Activin A-, AB- and B-responding cells were characterized by their responsiveness in cytosolic free calcium ([Ca2+])i) to four hypothalamic releasing hormones, CRH, GHRH, TRH and GnRH. First, rat pituitary cells responding to activin A, AB and B in [Ca2+]i were determined in a mixed population of pituitary cells. The populations of the activin A-, AB-, and B-responding cells were 13.9%, 9.3% and 13.2%, respectively. Overlapping of response among each population of activin- responding cells was present in some of the cells. The cells responding to activin A, AB, and B were then characterized by their responses to CRH, GHRH, TRH and GnRH. Most of the cells responding to activin A, AB, and B also responded to GHRH or TRH. These results reveal that there are distinct differences among each population of activin A-, AB- and B-responding cells and that there is still functional overlapping of responsiveness among these populations. The characterization of activin-responding cells suggests involvement of somatotropes and lactotropes in activin-induced biological events in the pituitary.

Activins↗

PubMed1994

Tumor necrosis factor-alpha (TNF-alpha) inhibits expression of mouse placental lactogen-II through TNF-alpha type-I but not type-II receptor.

The aim of this study was to determine whether TNF-alpha inhibits mPL-II secretion through TNF-RI or TNF-RII, and to investigate the gestational profile of TNF-RI and TNF-RII gene expression. The mouse trophoblast cells from day 12 pregnancy were cultured with or without agonistic polyclonal antibodies directed against the individual TNF-alpha receptors, and mPL-II secretion in the medium was assessed by RIA. Anti-TNF-RI antibody significantly inhibited the mPL-II secretion in a dose- and time-dependent manner, but anti-TNF-RII antibody did not. Moreover, the TNF-RII antibody did not influence the inhibitory effect of the TNF-RI antibody on mPL-II secretion. TNF-RI antibody inhibited the mPL-II gene expression by Northern blot analysis. Amount of the gene expression of TNF-RI in the second half of pregnancy was higher than those in the first half of pregnancy both in vitro and in vivo, although the gene expression of TNF-RII was not detectable by Northern blot analysis using poly(A)+RNA. These results suggest that TNF-RI is a main receptor for TNF-alpha in mouse placenta and that TNF-alpha may have an important role in regulating mPL-II secretion after midpregnancy.

Animals↗

PubMed1994

Inhibitory effect of interleukin-2 on histamine release from rat mast cells.

Interleukin-2 (IL-2) inhibited histamine release from rat mast cells induced by compound 48/80 in a concentration-dependent manner. The inhibitory effect of IL-2 on histamine release was also dependent on the length of the incubation period; the maximum inhibition was achieved at 8 h after IL-2 addition. Furthermore, IL-2 inhibited not only IP3 production but also 45Ca uptake in mast cells stimulated by compound 48/80. Since IL-2 enhanced [3H]-leucine uptake into mast cells, this suggests that protein synthesis may be related in some way with the inhibition of histamine release. IL-2 treatment augmented the synthesis of a protein having a molecular weight of approximately 35 kDa. From Western blotting analysis, it became clear that the production of lipocortin-I was augmented in rat mast cells by IL-2 treatment. The present study shows that IL-2 induces the synthesis of lipocortin-I in mast cells and that lipocortin-I may play some role in inhibiting histamine release from mast cells.

Animals↗

PubMed1994

Lateral movement of mast cell surface protein detected by gold-labeled anti-IgE and its relation with fodrin.

Rat mast cells were incubated with gold-conjugated concanavalin A and the movement of gold particles was observed using a polarization microscope. In resting cells, the movement of gold particles was very slow. When cells were stimulated with compound 48/80, the gold particles rapidly moved laterally, unrelated to granule extrusion. When sensitized mast cells were stimulated with gold-conjugated anti-IgE (anti-IgE-gold), patching of anti-IgE-gold was also observed. Immunofluorescence microscopy of rat mast cells stained with anti-fodrin antibody and rhodamine-phalloidin revealed that both fodrin and actin exist beneath the cell membrane forming a complicated network. After stimulation of the cells with anti-IgE-gold, the fodrin network was disrupted and thin fluorescence was observed homogeneously on the cell surface. By means of Western blotting, alpha-fodrin was detected in the membrane fraction of mast cells at the 240 kDa protein band. From the present study, it is suggested that disruption of the fodrin network may occur in association with the process leading to mast cell degranulation.

Animals↗

PubMed1994

Histamine-induced bi-directional differentiation of HL-60 cells towards neutrophils and eosinophils.

HL-60 cells, treated under alkaline conditions (pH 7.6) or acidic conditions (pH 7.2) for 2 months, were stimulated with histamine for 7 days. From the morphological examination and cytochemical characterization, it became clear that one of the clones treated in acidic pH differentiated to neutrophils and the other clone treated in alkaline medium differentiated to eosinophils after histamine-stimulation. The growth curve reached a maximum 4 days after stimulation. By means of in situ hybridization, it has been shown that the mRNA of major basic protein increased after histamine treatment only in the eosinophilic subclone, starting 4 days after stimulation. From the present study, it is suggested that when HL-60 cells were cultured under different pH conditions, commitment of lineages to the direction of either eosinophils or neutrophils takes place. Histamine may potently stimulate the further differentiation of both eosinophilic and neutrophilic clones.

Base Sequence↗

PubMed1994

The control of endothelin-1 secretion.

1. The human endothelin-1 (ET-1) gene, which is located on chromosome 6, contains cis-regulatory elements in the 5'-flanking region including the TPA-responsive element, nuclear factor 1 binding element and GATA motif. 2. The expression of preproendothelin-1 (PPET-1) mRNA is regulated by a mechanism involving receptor mediated mobilization of intracellular Ca2+ and activation of protein kinase C in endothelial cells. 3. Activation of protein kinase C results in the synthesis of c-Jun protein and the rapid dephosphorylation of c-Jun protein. Consequently, the binding activity of c-Jun protein to the TPA-responsive element increases, and this causes the induction of PPET-1 mRNA. 4. The microtubular system seems to play some important roles in ET-1 secretion, especially in the process of transferring the synthesized ET-1 to the cell surface of the endothelial cells. 5. The secretion of ET-1 from endothelial cells is also regulated by intracellular Ca2+ released from the Ca2+ store and by Ca2+-calmodulin complex. The phosphorylation of the myosin light chain, elicited by myosin light chain kinase and activated by Ca2+-calmodulin complex, facilitates the formation of filamentous myosin and actin which probably participate in ET-1 secretion especially in transporting the ET-1-containing vesicles towards the cell membrane in the stimulated endothelial cells. 6. Many cultured cells, other than endothelial cells, also secret ET-1 into the culture medium and this secretion can be stimulated by a variety of agents.

Calcium↗

PubMed1994

Inhibition of tumor necrosis factor-alpha and -beta secretion by lymphokine activated killer cells by transforming growth factor-beta.

Transforming growth factor-beta (TGF-beta) has a variety of immunosuppressive properties. We investigated the effect of TGF-beta secreted by glioblastoma (T98G) cells on the secretion of tumor necrosis factor-alpha and -beta (TNFs) by lymphokine activated killer (LAK) cells stimulated with tumor cells. The supernatant from T98G cells was preincubated with anti-TGF-beta 1 and -beta 2 neutralizing antibodies or untreated, and added to a coculture of LAK and Daudi cells. The neutralizing antibodies were added to LAK/Daudi and LAK culture, and natural human TGF-beta 1 and recombinant human TGF-beta 2 were also added to the LAK/Daudi culture. LAK cells were also cultured with T98G cells, of which the supernatant contained both active and latent forms of TGF-beta 1 and TGF-beta 2, and the neutralizing antibodies were added to the coculture. TNFs activity in the supernatants from LAK/Daudi cultures was examined by a specific bioassay. Addition of the supernatant from T98G cells to LAK/Daudi culture resulted in the inhibition of TNFs secretion by LAK cells. The inhibition was abrogated by the pretreatment of the supernatants with the anti-TGF-beta antibodies. Addition of TGF-beta 1 and TGF-beta 2 to LAK/Daudi culture inhibited TNFs secretion by LAK cells in a dose-dependent manner. Addition of anti-TGF-beta antibodies to LAK culture resulted in an increase of TNFs secretion. These results suggest that, if tumor cells have the capacity to convert TGF-beta from a latent to an active form, the active TGF-beta suppresses TNFs secretion by LAK cells stimulated with the tumor cells, and that TGF-beta secreted and activated by glioblastoma cells suppresses the propagation of immune reaction by inhibiting TNFs secretion by activated lymphocytes adjacent to tumor cells.

Glioblastoma↗

PubMed1994

Roles of prostaglandins and intracellular free calcium mobilisation in epidermal growth factor-induced proliferation of human amnion cells.

OBJECTIVE: To investigate the mechanisms which regulate the growth of human amnion cells. DESIGN: A prospective descriptive study. SUBJECTS: Women undergoing caesarean section at term before the onset of labour. INTERVENTIONS: Amnion cells were cultured in monolayer. MAIN OUTCOME MEASURES: Cell cycle analysis, intracellular calcium levels, prostaglandin (PG) production rates. RESULTS: Epidermal growth factor (EGF) stimulated intracellular Ca2+ mobilisation and PGE2 production in cultured amnion cells. The addition of a Ca2+ channel blocker (cobalt) or a Ca2+ chelator (EGTA) into the culture medium inhibited intracellular Ca2+ mobilisation and PGE2 production induced by EGF. The analysis of cell cycles showed that EGF induced the initiation of DNA synthesis and that the addition of cobalt or EGTA into the culture medium inhibited EGF-induced DNA synthesis. The addition of a cyclo-oxygenase inhibitor (indomethacin) inhibited PGE2 production and DNA synthesis induced by EGF without the effect on intracellular Ca2+ mobilisation. Moreover, the inhibitory effect of indomethacin on EGF-induced DNA synthesis was attenuated by the addition of exogenous PGE2 or PGF2 alpha. CONCLUSIONS: These data suggest that EGF induces an increase in intracellular Ca2+ levels and the rate of prostaglandin production which leads to proliferation of human amnion cells.

Amnion↗

PubMed1994

[Development of the research in the field of histamine release].

Histamine release from mast cells is intimately related with degranulation. When basic histamine releasers such as compound 48/80 were applied extracellularly to isolated rat mast cells by means of microelectrophoresis, localized degranulation was evoked near the tip of micropipet in a few seconds. In response to the second electrophoretic application at the opposite side of the membrane of the same mast cells, similar local degranulation was induced. This fact clearly indicates that local degranulation does not damage mast cells to the extent of blocking following degranulation. As intracellular electrophoretic application of compound 48/80 caused a swelling of mast cell, although no degranulation was elicited. When antigen-antibody reaction was induced in a single rat mesentery mast cell by means of microelectrophoresis, the application of antigen was made extracellularly or intracellularly. At the site of extracellular application, localized degranulation and histamine release were evoked. Histamine release was evidenced by the disappearance of histamine fluorescence in the degranulated area. Neither degranulation nor histamine release was induced by intracellular application of antigen. In freeze-fracture electronmicroscopy of the resting rat mast cells, intra-membrane particles (IMPs) were randomly distributed on the plasma membrane. When sensitized cells were exposed to antigen, IMPs were markedly dispersed so as to surround bulging regions of the membrane elicited by swollen granules. As the particles gathered at the periphery of the bulges, actually no particle was seen on the protuberant region. When rat mast cells loaded with quin 2 were exposed compound 48/80 in a Ca-free medium, a marked increase of quin 2 fluorescence was noticed, indicating that Ca2+ was released from intracellular Ca store. The binding of 45Ca was at its peak in the fractions where the highest activity of glucose-6-phosphatase, a marker enzyme for the endoplasmic reticulum, when organelles of mast cells were fractionated. This may indicate that intracellular Ca store is endoplasmic reticulum. It has been shown that microfilaments, and microtubules play some important roles in histamine release from rat mast cells. When permeabilized mast cells were stimulated with Ca2+, a translocation of protein kinase C from cytosol to membrane fraction was observed. This leads to phosphorylation of vimentin, one of intermediate filaments. In membrane skeletons of rat mast cells, alpha- and beta-fodrin, ankyrin and actin were found by means of western blotting analysis. It was supposed that membrane skeleton may be useful as a barrier between the plasma membrane and the granule membrane.

Actin Cytoskeleton↗

PubMed1994

Improved bioassay for the detection of transforming growth factor-beta 1 and beta 2 in malignant gliomas.

Growth inhibition assays using radioisotope or dye are used to detect transforming growth factor-beta (TGF-beta). Here, we describe a modified bioassay using crystal violet for the quantitative detection of TGF-beta 1 and TGF-beta 2. The procedure is based on staining Mv1Lu mink lung epithelial cells with crystal violet, followed by measurement of the absorbance at 570 nm in individual wells of a 96-well microtiter plate. The number of Mv1Lu cells correlated with the eluted dye intensity. The sensitivity of the bioassay to recombinant TGF-beta 1 and TGF-beta 2 increased approximately twofold by using only 500 Mv1Lu cells in microtiter wells. The bioassay was used to measure TGF-beta activity in the culture supernatant from glioblastoma cells. Culture supernatants were untreated or acid-activated to quantify the active or total TGF-beta, and neutralized with anti-TGF-beta 1 and/or anti-TGF-beta 2 antibody to measure the activity. Both TGF-beta 1 and TGF-beta 2 were detected in the untreated and acid-activated supernatants, and the amounts were calculated by extrapolating from the known recombinant TGF-beta 1 or TGF-beta 2 dilution curve. Our results show that the modified bioassay using crystal violet can measure the levels of TGF-beta 1 and TGF-beta 2 in culture supernatants from malignant glioma cells.

Biological Assay↗

PubMed1994

An autoimmune MRL/Mp-Ipr/Ipr mouse-derived monoclonal IgG antibody stimulates cytokine production in bone-marrow-derived cell line by cross-linking of a cell surface antigen and Fc receptor.

An IgG1 mAb 1G10 derived from an autoimmune MRL/Mp-Ipr/Ipr (MRL/Ipr) mouse has previously been shown to induce IL-3, TNF-alpha and IL-6 production, and autocrine growth in an IL-3-dependent myeloid cell line, FDC-P2/185-4. In the present study, we have attempted to further define the molecular mechanism responsible for the 1G10-induced activation of FDC-P2/185-4 cells. We have shown that 1G10 lacked anti-IgG1 rheumatoid factor activity, failing to generate self-associated immune complexes. Since 1G10 stimulated cells in an Fc gamma R-dependent manner, it seems likely that cross-linking of a cell surface antigen and Fc gamma R by 1G10 antibody is responsible for the stimulation of FDC-P2/185-4 cells. Among several mAb specific to surface antigens expressed on FDC-P2/185-4 cells (MHC class I, LFA-1, and Fc gamma R), only a mAb specific to the alpha chain of LFA-1 alpha was able to induce the IL-3 and Fc gamma R-dependent proliferation of FDC-P2/185-4 cells, similar to that induced by 1G10. Immunoprecipitation analysis revealed that 1G10 recognized a polypeptide with a molecular mass of 140 kilodaltons (p140), which differed from Fc gamma R and from LFA-1 alpha chain. These results suggest that cross-linking of not general but particular cell surface antigens and Fc gamma R stimulates FDC-P2/185-4 cells to produce cytokines resulting in their proliferation.

Animals↗

PubMed1994

Reinforcement effect of histamine on the differentiation of murine myeloblasts and promyelocytes: externalization of granulocyte colony-stimulating factor receptors induced by histamine.

Histamine and recombinant granulocyte colony-stimulating factor (rG-CSF) stimulated the differentiation of murine myeloblasts and promyelocytes to mature neutrophils. In connection with this, myeloperoxidase activity of these progenitor cells was decreased by either histamine or rG-CSF treatment. After pretreatment with histamine at 1 microM, both differentiation and the decrease in myeloperoxidase activity of myeloblasts and promyelocytes induced by rG-CSF were significantly augmented. Binding assays using 125I-labeled rG-CSF showed that the number of rG-CSF binding sites on the surface of neutrophil progenitor cells increased after histamine treatment. The histamine-induced increase in rG-CSF binding appeared to be definitely through H2 receptors. Furthermore, the increase in rG-CSF binding sites due to histamine treatment seemed to take place in association with the externalization of G-CSF receptors, because 1) the binding increase was observed in the presence of cycloheximide, 2) no concomitant increase in [3H]leucine uptake was elicited, and 3) colchicine and cytochalasin D effectively prevented the increase in rG-CSF binding due to histamine. In neutrophil progenitors, cAMP contents increased very rapidly and significantly after either histamine or rG-CSF treatment. Moreover, dibutyryl-cAMP increased rG-CSF binding to neutrophil progenitor cells in a dose-dependent fashion. However, when progenitor cells were pretreated with protein kinase A inhibitors, the histamine-induced increase in rG-CSF binding was remarkably decreased. This result seems to indicate that the stimulatory effects of histamine on rG-CSF binding to progenitor cells are intimately related to the cAMP-protein kinase A system in neutrophil progenitors. Moreover, c-myc mRNA expression in neutrophil progenitors was markedly reduced by either histamine or rG-CSF treatment. It was concluded that rG-CSF-induced differentiation of murine neutrophil progenitors was augmented by histamine pretreatment mainly due to an increase in rG-CSF receptors on these cells and this increase might be related to the externalization of rG-CSF receptors.

Animals↗

PubMed1994

Effects of antiallergic agents including levocabastine on experimental rhinitis in rats.

Topical application of levocabastine hydrochloride (-)-[3S-[1(cis)-3 alpha,4 beta]]-1-[4-cyano-4-(4-fluorophenyl) cyclohexyl]-3-methyl-4-phenyl-4-piperidinecarboxylic acid monohydrochloride, inhibited the increase in dye leakage into the nasal cavity induced not only by antigen in actively sensitized rats but also by histamine in non-sensitized rats. The potency of levocabastine was stronger than that of ketotifen in inhibiting the increase of dye leakage in both cases. In addition, levocabastine as well as ketotifen exerted a more potent inhibition of the dye leakage induced by histamine than that induced by antigen. Levocabastine also exerted a significant inhibition on the dye leakage induced by substance P; again the effect of levocabastine was more potent than that of ketotifen. On the other hand, levocabastine elicited no remarkable influence on the dye leakage induced by either acetylcholine or platelet activating factor. However, ipratropium and (RS)-2-methoxy-3-(octadecylcarbamoyloxy)propyl 2-(3-thiazolio)ethyl phosphate were effective when the corresponding agonists were perfused, respectively.

Acetylcholine↗