• The Korean Journal of Physiology and Pharmacology
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• v.23 no.5
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• pp.357-366
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• 2019

$G{\alpha}_q$-coupled receptor stimulation was implied in the activation process of transient receptor potential canonical (TRPC)1/4 and TRPC1/5 heterotetrameric channels. The inactivation occurs due to phosphatidylinositol 4,5-biphosphate ($PI(4,5)P_2$) depletion. When $PI(4,5)P_2$ depletion was induced by muscarinic stimulation or inositol polyphosphate 5-phosphatase (Inp54p), however, the inactivation by muscarinic stimulation was greater compared to that by Inp54p. The aim of this study was to investigate the complete inactivation mechanism of the heteromeric channels upon $G{\alpha}_q$-phospholipase $C{\beta}$ ($G{\alpha}_q-PLC{\beta}$) activation. We evaluated the activity of heteromeric channels with electrophysiological recording in HEK293 cells expressing TRPC channels. TRPC1/4 and TRPC1/5 heteromers undergo further inhibition in $PLC{\beta}$ activation and calcium/protein kinase C (PKC) signaling. Nevertheless, the key factors differ. For TRPC1/4, the inactivation process was facilitated by $Ca^{2+}$ release from the endoplasmic reticulum, and for TRPC1/5, activation of PKC was concerned mostly. We conclude that the subsequent increase in cytoplasmic $Ca^{2+}$ due to $Ca^{2+}$ release from the endoplasmic reticulum and activation of PKC resulted in a second phase of channel inhibition following $PI(4,5)P_2$ depletion.

• 대한핵의학회:학술대회논문집
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• 1990.04a
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• pp.185.1-185.1
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• 1990

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2002.05a
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• pp.123-123
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• 2002

• Proceedings of the PSK Conference
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• 2001.10a
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• pp.158.1-158.1
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• 2001

• Tuberculosis and Respiratory Diseases
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• v.82 no.1
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• pp.71-80
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• 2019

Background: Efficacy and safety of tiotropium bromide, a muscarinic receptor antagonist, in treatment of asthma have been reported. However, its effect on airway remodeling in chronic asthma of the elderly has not been clearly verified. The objective of this study was to investigate the effect of tiotropium and expression of muscarinic receptors as its related mechanism in an aged mouse model of chronic asthma with airway remodeling. Methods: BALB/c female mice age 6 weeks, 9 and 15 months were sensitized and challenged with ovalbumin (OVA) for three months. Tiotropium bromide was administered during the challenge period. Airway hyperresponsiveness (AHR) and pulmonary inflammation were measured. Parameters of airway remodeling, and expression levels of $M_2$ and $M_3$ receptors were examined. Results: Total cell with eosinophils, increased in the OVA groups by age, was decreased significantly after treatment with tiotropium bromide, particularly in the age group of 15 months. AHR and levels of interleukin (IL)-4, IL-5, and IL-13 were decreased, after tiotropium administration. In old aged group of 9- and 15-months-treated groups, hydroxyproline contents and levels of ${\alpha}$-smooth muscle actin were attenuated. Tiotropium enhanced the expression of $M_2$ but decreased expression of $M_3$ in all aged groups of OVA. Conclusion: Tiotropium bromide had anti-inflammatory and anti-remodeling effects in an aged mouse model of chronic asthma. Its effects seemed to be partly mediated by modulating expression $M_3$ and $M_2$ muscarinic receptors. Tiotropium may be a beneficial treatment option for the elderly with airway remodeling of chronic asthma.

• Biomolecules & Therapeutics
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• v.28 no.4
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• pp.328-336
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• 2020

Diabetes mellitus affects the colonic motility developing gastrointestinal symptoms, such as constipation. The aim of the study was to examine the role of intracellular signaling pathways contributing to colonic dysmotility in diabetes mellitus. To generate diabetes mellitus, the rats were injected by a single high dose of streptozotocin (65 mg/kg) intraperitoneally. The proximal colons from both normal and diabetic rats were contracted by applying an electrical field stimulation with pulse voltage of 40 V in amplitude and pulse duration of 1 ms at frequencies of 1, 2, 4, and 6 Hz. The muscle strips from both normal rats and rats with diabetes mellitus were pretreated with different antagonists and inhibitors. Rats with diabetes mellitus had lower motility than the control group. There were significant differences in the percentage of inhibition of contraction between normal rats and rats with diabetes mellitus after the incubation of tetrodotoxin (neuronal blocker), atropine (muscarinic receptor antagonist), prazosin (α₁ adrenergic receptor antagonist), DPCPX (adenosine A1 receptor antagonist), verapamil (L-type Ca²⁺ channel blocker), U73122 (PLC inhibitor), ML-9 (MLCK inhibitor), udenafil (PDE₅ inhibitor), and methylene blue (guanylate cyclase inhibitor). The protein expression of p-MLC and PDE₅ were decreased in the diabetic group compared to the normal group. These results showed that the reduced colonic contractility resulted from the impaired neuronal conduction and decreased muscarinic receptor sensitivity, which resulted in decreased phosphorylation of MLC via MLCK, and cGMP activity through PDE₅.

• Journal of Applied Biological Chemistry
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• v.63 no.4
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• pp.365-373
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• 2020

We previously reported the potential of Senna tora L. seeds fermented by Lactobacillus casei (FSL) as a laxative agent in a loperamide-induced constipation rat model. Here, we examine the mechanism of action of FSL and its bioactive compound, revealed herein, on loperamide-induced constipation Sprague Dawley rat model. We identified the compound aurantio-obtusin (AO) using HPLC quantitative analysis. Rats were randomly assigned to six experimental groups (eight rats each)-normal and constipated groups (loperamide, FSL [100, 300, 500 mg/kg], and AO [1 mg/kg]). The FSL and AO-treated group showed an increase in the frequency, amount, and water content of feces in the constipated rat. Moreover, FSL and AO increased the intestinal transit speed in the constipated rat. Histological analysis revealed that FSL and AO recovered the intestinal mucus, the number of goblet cells, as well as thickness of the mucosa layer and muscle. Furthermore, the protein levels of the muscarinic acetylcholine receptor M3, which is involved in intestine contraction, were recovered in the FSL and AO-treated group. Its downstream signaling pathway (p-protein kinase C) was recovered by FSL and AO treatment. In conclusion, fermentation of S. tora L. seeds increases AO, which improves intestinal function, indicating that FSL is effective for treating constipation.

• BMB Reports
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• v.47 no.10
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• pp.552-557
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• 2014

The main purpose of this study was to investigate whether type 3 muscarinic acetylcholine receptor (M3R) dysfunction induced vascular hyperpermeability. Transwell system analysis showed that M3R inhibition by selective antagonist 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP) and small interfering RNA both increased endothelial permeability. Using coimmunoprecipitation and Western blot assay, we found that M3R inhibition increased VE-cadherin and ${\beta}$-catenin tyrosine phosphorylation without affecting their expression. Using PTP1B siRNA, we found that PTP1B was required for maintaining VE-cadherin and ${\beta}$-catenin protein dephosphorylation. In addition, 4-DAMP suppressed PTP1B activity by reducing cyclic adenosine monophosphate (cAMP), but not protein kinase $C{\alpha}$ ($PKC{\alpha}$). These data indicate that M3R preserves the endothelial barrier function through a mechanism potentially maintaining PTP1B activity, keeping the adherens junction proteins (AJPs) dephosphorylation.

• Biomolecules & Therapeutics
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• v.12 no.2
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• pp.101-107
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• 2004

Repeated administration of psychostimulants such as amphetamines increases locomotor activity in rodents. These drugs, including methamphetamine, enhance dopaminergic neurotransmission and result in hyper-locomotion and behavioral sensitization. It is well known that the existence of a complex balance between the cholinergic and dopaminergic systems in the central nervous system. Thus, behavioral sensitization by methamphetamine may be related to the expression of the M1 muscarinic acetylcholine receptors gene. The present study investigated the changes of M1R mRNA in hyperlocomotor activity and behavioral sensitization by methamphetamine (2 mg/kg) in mice. Our results showed that M1R mRNA expression was increased in the frontal cortex and the hippocampus region (the CA2 region) in the acute methamphetamine administered group compared to the saline administered group. In the chronic group, M1R mRNA expression was increased in the frontal cortex ill1d the hippocampus regions (CA2 and DG regions) in melt1amphetamine administered group compared to saline control group. These results indicate that acute or chronic treatment of mathamphetamine leads to the region-specific changes in mRNA expression levels of M1R. Therefore, Therefore, the present result suggests that M1R may play a role in modulating of methamphetamine-induced behavioral sensitization in mice.

• Korean Journal of Veterinary Research
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• v.34 no.1
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• pp.63-67
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• 1994

Berberine $(10^{-7}-10^5M)$ increased the contractility dose-dependently in isolated rabbit ileal and jejunal segments. Atropine and hemicholinium abolished this response but not mecamylamine. Berberine$(10^{-8}-10^5M)$ enhanced the transmurally-stimulated(80 V, 0.5 ms, 0.05 Hz) twitch response in the isolated guinea-pig ileal segments. Atropine and hemicholinium also abolished this response but not mecamylamine. Effect of KCI, carbachol and histamine were not affected by pretreatment with berberine$(10^{-5}M)$. The results of our study suggest that berberine increases the intestinal contractility by increasing a small amount of acetylcholine release from the postganglionic parasympathetic nerve terminal but not by a direct activation of muscarinic receptors.