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Your search keyword '"Isohama Yoichiro"' showing total 40 results
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40 results on '"Isohama Yoichiro"'

9. Goreisan alleviates cerebral edema: Possibility of its involvement in inhibiting aquaporin‐4 function.

Author

Shimizu, Tomofumi, Murakami, Kazuhito, Matsumoto, Chinami, Kido, Toshitaka, and Isohama, Yoichiro

Subjects
CEREBRAL edema, HYDROCEPHALUS, MAGNETIC resonance imaging, XENOPUS laevis, LABORATORY mice
Abstract

Aim: In Japan, goreisan (GRS) is used to alleviate cerebral edema and relieve headaches. Although improvement of water maldistribution in the brain may be one of the mechanisms of action of GRS for cerebral edema and headache, scientific evidence is limited. Here, we aimed to investigate the action mechanism of GRS against cerebral edema and headaches, focusing on water dynamics in the brain. Methods: We used a well‐established mouse model of cerebral edema to evaluate the effects of GRS on related symptoms and brain water content. The mouse model was subjected to magnetic resonance imaging (MRI) using H217O to assess water dynamics in the brain. The effect of GRS on water permeability through aquaporin‐4 (AQP4) was also examined in vitro. Results: GRS inhibited the loss of righting reflex and improved survival in the mouse model by ameliorating the increase in brain water content. The MRI evaluation of water dynamics suggested that GRS inhibited water influx into the brain. Evaluation of water permeability via AQP4 in Xenopus laevis oocytes and HEK293 cells showed that GRS inhibited AQP4 function. Conclusion: GRS suppressed the ubiquity of water in the brain in a mouse model of cerebral edema, suggesting inhibition of AQP4 function (not AQP4 expression) as one of the action mechanisms of GRS. Our findings provide fundamental evidence for the clinical efficacy of GRS against cerebral edema and headaches. [ABSTRACT FROM AUTHOR]

Published
2023
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39. Ezrin Regulates Ca 2+ Ionophore-Induced Plasma Membrane Translocation of Aquaporin-5.

Author

Muroi, Shin-ichi and Isohama, Yoichiro

Subjects
CELL membranes, EZRIN, AQUAPORINS, MEMBRANE proteins, EXOCRINE glands, SWEAT glands
Abstract

Aquaporin-5 (AQP5) is selectively expressed in the apical membrane of exocrine glands, such as salivary, sweat, and submucosal airway glands, and plays important roles in maintaining their secretory functions. Because AQP5 is not regulated by gating, localization on the plasma membrane is important for its water-permeable function. Ezrin is an ezrin–radixin–moesin family protein that serves as a crosslinker between the plasma membrane and actin cytoskeleton network. It plays important roles in translocation of various membrane proteins to mediate vesicle trafficking to the plasma membrane. In this study, we examined the effects of ezrin inhibition on membrane trafficking of AQP5. Ezrin inhibition selectively suppressed an ionomycin-induced increase in AQP5 translocation to the plasma membrane of mouse lung epithelial cells (MLE-12) without affecting the steady-state level of plasma membrane AQP5. Taken together, our data suggest that AQP5 translocates to the plasma membrane through at least two pathways and that ezrin is selectively involved in a stimulation-dependent pathway. [ABSTRACT FROM AUTHOR]

Published
2021
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40. ATP Increases Ciliary Beat Frequency and Ciliary Bend Angle through Distinct Purinergic Receptors in Bronchial Ciliary Cells Isolated from Mice.

Author

Sekiya T, Murakami K, and Isohama Y

Subjects
Animals, Mice, Mucociliary Clearance physiology, Male, Receptors, Purinergic P2X4 metabolism, Receptors, Purinergic P2Y1 metabolism, Receptors, Purinergic metabolism, Signal Transduction, Cilia metabolism, Cilia physiology, Adenosine Triphosphate metabolism, Bronchi cytology
Abstract

Airway ciliary cells are components of the mucociliary transport system and play an important role in sweeping out small particles, such as bacteria and viruses, towards the oropharynx by the action of beating cilia. Several lines of evidence have shown that the ciliary beat is under the regulation of the purinergic system; however, the subtype of receptor and the intracellular signaling pathways involved in the activation of ciliary movement remain to be elucidated. In addition, although the activity of ciliary movement comprises two parameters, the ciliary beat frequency (CBF) and ciliary bend angle (CBA), few reports have analyzed CBA. In this study, we examined the effects of ATP and other purinergic ligands on both CBF and CBA and demonstrated that the purinergic signaling requirements for CBF and CBA are different, with CBF mediated by P2Y 1 receptor activation and CBA mediated by the P2X4 receptor.

Published
2024
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