| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2001: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2000: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Research Abstract |
The role of nitric oxide (NO) in ciliary beat frequency (CBF) regulation in airway epithelial cells were studied using cultured rat tracheal epithelial cells. Images of ciliated cells were videotaped using a phase-contrast microscope. CBF was increased by NOC-12 and GSNO (NO donors), L-arginine (a NO precursor), 8-Br-cGMP, zaprinast (a cGMP-specific phosphodiesterase inhibitor), isoproterenol (a beta-receptor agonist), 8-Br-cAMP, amrinon (a phosphodiesterase type III inhibitor) and rolipram (a cAMP-specific phosphodiesterase inhibitor). The enhancement of CBF by L-arginine, 8-Br-cGMP, isoproterenol and 8-Br-cAMP was inhibited by L-NMMA (a NO synthase inhibitor), ODQ (a soluble guanylyl cyclase (sGC)-selective inhibitor) or KT5823 (a protein kinase G (PKG)-selective inhibitor). L-NMMA, ODQ or KT5823 alone did not change CBF. The enhancement of CBF by isoproterenol and 8-Br-cAMP was inhibited by KT5720 (a protein kinase A (PKA)-selective inhibitor). The production of NO using diaminofluo
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rescein (DAF, an indicator for NO) and its relationship with CBF were studied. The ciliated cells pretreated with DAF became fluorescent, but no fluorescence was detected in the cells without the pretreatment. The fluorescent intensity and CBF increased by L-arginine, not by D-arginine. The enhancements by L-arginine were nearly abolished by L-NMMA, not by D-NMMA. D-arginine, L-NMMA and D-NMMA alone did not change fluorescent intensity and CBF. There was a significant positive correlation between the increases of fluorescent intensity and CBF. These results demonstrate that rat tracheal clliated epithelial cells produce NO, NO stimulattes CBF in autocrine/paracrine manner, the NO-sGC-PKG pathway is involved in the regulation of ciliary motility, and that the pathway is involved in CBF stimulation via the beta-adrenoreceptor-cAMP-PKA pathway. The effect of propofol, an intravenous anesthetic, on CBF was investigated. Propofol stimulated CBF dose dependently. The enhancement of CBF by propofol was inhibited by L-NMMA, ODQ or KT5823. These results demonstrate that propofol stimulates CBF via the NO-sGC-PKG pathway. Less
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