• Herbal Formula Science
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• v.30 no.2
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• pp.37-44
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• 2022

Objectives : The purpose of this study was to examine the effects of Alisma canaliculatum Extract (ACE) on pacemaker potentials of small and large intestinal interstitial Cells of Cajal (ICC) in mice. Methods : We used enzymatic digestions to dissociate the ICC in the small and large intestine in mice. The whole-cell patch-clamp method was used to record pacemaker potentials in ICC. Results : 1. The ICC generated the pacemaker potentials in small intestine in mice. ACE (0.1-1mg/ml) induced membrane depolarization and decreased frequency with concentration-dependent manners. 2. Pretreatment with a Ca²⁺ free solution, Na⁺ 5 mM solution or 2-APB, a nonselective cation channel blocker, stopped the small intestinal ICC pacemaker potentials. In the case of Ca²⁺-free solution, Na⁺ 5 mM solution or 2-APB, ACE had no effects on the membrane depolarizations in small intestinal ICC. 3. The ICC generated the pacemaker potentials in large intestine in mice. Membrane depolarization appears regularly in the small intestine, but irregularly in the large intestine. ACE induced membrane depolarization (0.1-1mg/ml) and increased frequency (0.1-0.5mg/ml). 4. Pretreatment with a Ca²⁺ free solution, Na⁺ 5 mM solution or 2-APB, stopped the large intestinal ICC pacemaker potentials. In the case of Ca²⁺-free solution, Na⁺ 5 mM solution or 2-APB, ACE depolarized the membrane depolarizations in large intestinal ICC. 5. In mice, intestinal transit rate (ITR) values were dose-dependently decreased by the intragastric administration of ACE. Conclusions : These results suggest that ACE can regulate the pacemaker activity of ICC and the reaction by ACE is different from the small and large intestinal ICC, and the control of the intestinal motion by ACE may be caused by many complex processes.

• BMB Reports
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• v.55 no.11
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• pp.565-570
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• 2022

Pulmonary arterial hypertension (PAH) is a progressive and devastating disease whose pathogenesis is associated with a phenotypic switch of pulmonary arterial vascular smooth muscle cells (PASMCs). Bone morphogenetic protein (BMP) signaling and potassium two pore domain channel subfamily K member 3 (KCNK3) play crucial roles in PAH pathogenesis. However, the relationship between BMP signaling and KCNK3 expression in the PASMC phenotypic switching process has not been studied. In this study, we explored the effect of BMPs on KCNK3 expression and the role of KCNK3 in the BMP-mediated PASMC phenotypic switch. Expression levels of BMP receptor 2 (BMPR2) and KCNK3 were downregulated in PASMCs of rats with PAH compared to those in normal controls, implying a possible association between BMP/BMPR2 signaling and KCNK3 expression in the pulmonary vasculature. Treatment with BMP2, BMP4, and BMP7 significantly increased KCNK3 expression in primary human PASMCs (HPASMCs). BMPR2 knockdown and treatment with Smad1/5 signaling inhibitor substantially abrogated the BMP-induced increase in KCNK3 expression, suggesting that KCNK3 expression in HPASMCs is regulated by the canonical BMP-BMPR2-Smad1/5 signaling pathway. Furthermore, KCNK3 knockdown and treatment with a KCNK3 channel blocker completely blocked BMP-mediated anti-proliferation and expression of contractile marker genes in HPAMSCs, suggesting that the expression and functional activity of KCNK3 are required for BMP-mediated acquisition of the quiescent PASMC phenotype. Overall, our findings show a crosstalk between BMP signaling and KCNK3 in regulating the PASMC phenotype, wherein BMPs upregulate KCNK3 expression and KCNK3 then mediates BMP-induced phenotypic switching of PASMCs. Our results indicate that the dysfunction and/or downregulation of BMPR2 and KCNK3 observed in PAH work together to induce aberrant changes in the PASMC phenotype, providing insights into the complex molecular pathogenesis of PAH.

• Korean Journal of Radiology
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• v.20 no.5
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• pp.719-728
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• 2019

Objective: To investigate the diagnostic validity of coronary computed tomography angiography (cCTA) in vasospastic angina (VA) and factors associated with discrepant results between invasive coronary angiography with the ergonovine provocation test (iCAG-EPT) and cCTA. Materials and Methods: Of the 1397 patients diagnosed with VA from 2006 to 2016, 33 patients (75 lesions) with available cCTA data from within 6 months before iCAG-EPT were included. The severity of spasm (% diameter stenosis [%DS]) on iCAGEPT and cCTA was assessed, and the difference in %DS (Δ%DS) was calculated. Δ%DS was compared after classifying the lesions according to pre-cCTA-administered sublingual nitroglycerin (SL-NG) or beta-blockers. The lesions were further categorized with %DS ≥ 50% on iCAG-EPT or cCTA defined as a significant spasm, and the diagnostic performance of cCTA on identifying significant spasm relative to iCAG-EPT was assessed. Results: Compared to lesions without SL-NG treatment, those with SL-NG treatment showed a higher Δ%DS (39.2% vs. 22.1%, p = 0.002). However, there was no difference in Δ%DS with or without beta-blocker treatment (35.1% vs. 32.6%, p = 0.643). The significant difference in Δ%DS associated with SL-NG was more prominent in patients who were aged < 60 years, were male, had body mass index < 25 kg/m², and had no history of hypertension, diabetes, or dyslipidemia. Based on iCAG-EPT as the reference, the per-lesion-based sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of cCTA for VA diagnosis were 7.5%, 94.0%, 60.0%, 47.1%, and 48.0%, respectively. Conclusion: For patients with clinically suspected VA, confirmation with iCAG-EPT needs to be considered without completely excluding the diagnosis of VA simply based on cCTA results, although further prospective studies are required for confirmation.

• The Korean Journal of Pharmacology
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• v.31 no.1 s.57
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• pp.11-15
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• 1995

Serotonergic neurons in medulla oblongata play an important role in the endogenous descending pain inhibitory system. To illucidate the factors involved in the regulation of medullary serotonergic neurons, we studied the effects of cholecystokinin (CCK) and agents acting on various second messenger systems on 5-hydroxytryptamine (5-HT) release from cultured neurons of rat fetal (gestational age 14th day) medulla oblongata. Cultured cells maintained for 10 days in vitro were stimulated for 48 hours with CCK or other neuropeptides at 10 micromolar concentration. CCK ($10{\mu}M$) and substance P ($10{\mu}M$) significantly increased. 5-HT release. However, somatostatin, proctolin, thyrotropin releasing hormone, and interleukin-6 did not have any effects on 5-HT release. Nimodipine ($1{\mu}M$), a calcium channel blocker, almost completely, and calmidazolium ($1{\mu}M$), a calmodulin antagonist, significantly inhibited the CCK-induced 5-HT release. The total 5-HT content (intracellular 5-HT plus released 5-HT) was significantly increased by CCK. However, the intracellular 5-HT content was not significantly changed by CCK. Forskolin ($5{\mu}M$), an adenylate cyclase activiator, but not $2{\mu}M$ phorbol myristate acetate (PMA), a protein kinase C activator, significantly enhanced 5-HT release. The total 5-HT content (intracellular 5-HT plus released 5-HT) was significantly increased by forskolin. However, the intracellular 5-HT content was not significantly changed by forskolin. PMA had no effect on intracellular 5-HT levels. These results suggest that CCK regulates serotonergic neurons in the medulla oblongata by enhancing 5-HT secretion through calcium influx and caimodulin, and that cyclic AMP system but not protein kinase C system is involved in 5-HT release.

• Clinical and Experimental Pediatrics
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• v.52 no.6
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• pp.689-695
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• 2009

Purpose : To examine the effect of bosentan, a dual endothelin receptor (ER) antagonist, on the development of monocrotaline (MCT)-induced pulmonary hypertension in rats by especially focusing on the pulmonary vascular morphology changes. Methods : Sprague-Dawley rats were treated as follows: controls received a subcutaneous saline injection, MCT-treated rats received a subcutaneous MCT injection, and bosentan-treated rats received a MCT injection followed by treatment with bosentan (20 mg/kg/day). To assess the effects of ER blockade on the time course, the animals were exsanguinated, and their hearts and lungs were dissected after 7, 14, or 28 days. Results : The mean body weights of the MCT- and bosentan-treated rats were significantly lower than that of the control rats on days 7, 14, and 28. Bosentan administration significantly inhibited the progression of right ventricular hypertrophy on day 28 (right ventricle/[left ventricle＋septum]: $0.71{\pm}0.10$ in MCT-treated rats vs. $0.49{\pm}0.09$ in bosentan-treated rats; P<0.05). Quantitative analysis of peripheral pulmonary arteries revealed that the increase in medial wall thickness after MCT injection was significantly attenuated in the bosentan-treated rats on day 28 ($49.96{\pm}10.06%$ in MCT-treated rats vs. $47.09{\pm}10.48%$ in bosentan-treated rats; P<0.05). In addition, the increase in the number of intra-acinar muscular arteries after MCT injection was reduced by bosentan on days 14 and 28. Conclusion : Bosentan administration in intermediate doses exerts inhibitory effects on lung vascular hypertrophy and right ventricular hypertrophy during the development of MCT-induced pulmonary hypertension in rats.

• Applied Biological Chemistry
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• v.44 no.3
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• pp.148-152
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• 2001

This study investigated the role of excitatory amino acid systems in the initiation of organophosphate-induced seizures and brain damages in rats through quantitative in vivo microdialysis. Microdialysates were collected from the hippocampus of rat brain, treated with diisopropylfluorophosphate (DFP; 2.67 mg/kg, s.c.) alone, and/or atropine sulfate (15 mg/kg, i.m.) and procyclidine (30 mg/kg, i.m.). The protective effects of atropine, a muscarinic blocker, and/or procyclidine, a N-methyl-D-aspartate and cholinergic antagonist, against DFP were examined. DFP treatment increased the levels of aspartate (Asp) and glutamate (Glu) significantly in the hippocampal persuate with the induction of seizures. Treatment of procyclidine could effectively block the increase of Asp and Glu levels. Atropine treatment showed no significant anticonvulsive effects against DFP-induced seizures. The increases of Asp and Glu levels by DFP were also completely blocked through the combined treatment of atropine and procyclidine. Histopathological findings on the hippocampus confirmed the above results. More effective protection was observed through the treatments of procyclidine alone or of both procyclidine and atropine than atropine alone against DFP-induced brain damage. Procyclidine was shown to be effective in DFP-induced seizures.

• The Korean Journal of Pharmacology
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• v.28 no.1
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• pp.81-89
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• 1992

Enuresis is a common voiding disorder among children. There are several therapeutic regimens for the disorder available today; behavioral therapies, psychotherapy, bladder training, sleep interruption, hypnosis and drug therapy. Recently, the efficacy of drug therapy has been acknowledged, particularly of antidepressants. Among the tricyclic antidepressants, imipramine is most frequently employed for the treatment of enuresis. Present study was undertaken to investigate the mechanism of imipramine on the contractility of urinary bladder in relation to the calcium modulation using isolated strips of rat detrusor urinae. 1. The electric fileld stimulation-induced contraction was abolished by imipramine, but partially inhibited by atropine. 2. Imipramine reduced the basal tone and diminished the phasic activity of detrusor muscle concentration-dependently, which was similar to that of diltiazem, a calcium channel blocker. 3. Imipramine suppressed the maximal responses and shifted the concentration-response curves of bethanechol and ATP to right. 4. Imipramine inhibited the calcium-induced recovery of tension in calcium-free physiologic salt solution (PSS) with a mode of action similar to that of diltizaem. 5. A23187, a calcium ionophore recovered the basal tone which had been reduced by imipramine in normal PSS. 6. In calcium-free PSS, A23187 could recover the abolished basal tone with the pretreatment of imipramine, but it exerted a partial recovery with the pretreatment of TMB-8, an inhibitor of intracellular calcium release. Based on these results, it is suggested that the inhibitory action of imipramine on the detrusor muscle exerted in part by blockade of the muscarinic and purinergic receptors, and interference with the influx of extracellular calcium, but not with the release of intracellular stored calcium, is involved in its mechanism of action.

• Clinical and Experimental Pediatrics
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• v.49 no.4
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• pp.439-445
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• 2006

Purpose : ${\alpha}$-Galactosylceramide (${\alpha}$-GalCer)-stimulated human $V{\alpha}24$ natural killer T (NKT) cells exert antitumor activity against some leukemia in a CD1d dependent and TCR-mediated manner, but could not kill CD1d - negative neuroblastoma (NB) cells. There are few reports about the direct antitumor effect of highly secreted cytokines by these cells on activation. In this study, using a cell-free supernatant (SPN) collected from plate bound hCD1d/${\alpha}$ GalCer tetramers-stimulated NKT cells, we examined whether they could be helpful in the immunotherapeutic treatment of NB. Methods : Cells were cultured in IMDM. The cytokines produced by NKT cells were measured with Cytometric Bead Array (CBA) analysis. Cell viability was evaluated by calcein-AM fluorescence with digital image microscopy scanning (DIMSCAN). The percentage of specific apoptosis was calculated by flow cytometric detection of apoptosis using annexin V and 7-AAD. Results : The activated NKT cells secreted high levels of IL-2, INF-${\gamma}$, TNF-${\alpha}$. The SPN was significantly cytotoxic against four out of eight tested NB cell lines, through mainly apoptosis as evidenced by annexin-V staining and inhibition with the pretreatment of pancaspase blocker. This apoptosis was significantly inhibited when anti-TNF-${\alpha}$ and anti-IFN-${\gamma}$ neutralizing mAbs were used separately and it was completely abolished when the two mAbs were combined. Conclusion : IFN-${\gamma}$ and TNF-${\alpha}$ produced by NKT cells could exert synergistically direct antitumor activity through apoptosis on some NB cell lines.

• Korean Journal of Veterinary Research
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• v.39 no.5
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• pp.878-895
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• 1999

Ischemic preconditioing (IPC), i.e., a preliminary brief episode of ischemia and reperfusion, has been shown to reduce the cell damage induced by long ischemia and reperfusion. Superoxide radical which is produced during reperfusion after ischemia was recognized as a factor of the ischemic injury and it is dismutated into $H_2O_2$ and $O_2$ by two types of intracellular superoxide dismutase (SOD), Cu,Zn-SOD in cytoplasm and Mn-SOD in mitochondria. Recently oxygen free radicals are suggested to induce the apoptosis, however mechanism of the reduced apoptosis by ischemic preconditioing was unknown, while many studies performed in mammalian heart indicated that ATP-sensitive $K^+$ ($K_{APT}$) channel activation related with the protective effects. The aim of present study is to investigate 1) whether IP upregulate the Cu,Zn-SOD and Mn-SOD activities, and 2) whether ischemic preconditioning decreases apoptosis via $K_{APT}$ channel activation in timely reperfused skeletal muscle after long ishemia. The experimental animals, Sprague-Dawley rats weighing 250~300g, were divided into 8 groups; 1) control group, 2) ischemic preconditioning only groups, 3) pinacidil, a $K_{APT}$ channel opener, treatment only groups, 4) glibenclamide, a $K_{APT}$ channel blocker, treatment only groups, 5) ischemia groups, 6) ischemia after IPC groups, 7) ischemia and pinacidil treatment groups, and 8) IP and ischemia after glibenclamide pretreatment groups. Animals of the control group were administered with the vehicle (DMSO) alone. Pinacidil (1mg/kg) was administered intravenously 5 minutes after initiation of ischemia, and glibenclamide (0.5mg/kg) was injected intravenously 20 minutes before IPC. In rats that were ischemic preconditioned, the left common iliac artery was occluded for 5 minutes followed by 5 minutes of reperfusion by three times using vascular clamp. Ischemia was done by occlusion of the same artery for 4 hours. The specimens of left rectus femoris muscle were obtained immediately (0 hour), 12 hours, 24 hours after drug administrations, IP or ischemia and reperfusion. The immunoreactivities of SOD and its alterations were observed by use of sheep antihuman Cu,Zn-SOD and Mn-SOD antibodies on the $10{\mu}m$ cryosections. The incidencies of apoptosis were observed by TUNEL methods with in situ apoptosis detection kit on $6{\mu}m$ paraffine section. The results obtained were as follows : 1. After IPC, immunoreactivities of Cu,Zn-SOD mainly in the small-sized fibers were increased by 24 hours, that of Mn-SOD at 0 hour and 24 hours. 2. No significant changes in immunoreactivities of SOD was observed in the pinacidil and in the glibenclamide treatment only groups, and in the ischemia only groups. 3. The immunoreactivities of the Cu,Zn-SOD were increased in the ischemia after IPC groups and the ischemia and pinacidil treatment groups. 4. The immunoreactivities of the Cu,Zn-SOD in the IPC and ischemia after glibenclamide pretreatment groups were not increased except for the 12 hours reperfusion group. But, Mn-SOD immunoreactivities were increased in the 0 hours, 12 hours and 24 hours after reperfusion. 5. In the control group, the IPC only groups, and the pinacidil treatment only groups, negative or trace apoptotic reactions were observed, but the positive apoptotic reaction occured in the glibenclamide treatment groups. 6. Moderate or many number of apoptosis were revealed in the ischemia groups, and also the IPC and ischemia after glibenclamide pretreatment group except for 12 hours and 24 hours after reperfusion. However, the incidence of apoptosis was decreased in the ischemia after IPC groups and in the ischemia and pinacidil treatment groups. 7. There is a coincidence between the increase of Cu,Zn-SOD immunoreactivities and the decrease of apoptosis in the presence of ischemia and reperfusion. These results suggest that the protective effects of ishemic preconditioing may related to the SOD activation, and the ischemic preconditioning decreases the apoptosis partially via $K_{APT}$ channel activation in timely reperfused rat skeletal muscle. It is also suggested that inhibition of apoptosis by IPC may related with the SOD activation.

• Journal of Chest Surgery
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• v.42 no.5
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• pp.588-596
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• 2009

Background: To clarify the effect of hypoxia on vascular contractility, we tried to show whether hypoxia induced the release of endothelium-derived relaxing factor (EDRF) and the nature of the underlying mechanism for this release. Material and Method: Isometric contractions were observed in rabbit aorta, and the released EDRF from the rabbit aorta was bioassayed by using rabbit denuded carotid artery. The intracellular $Ca^{2+}$ concentration ($[Ca^{2+}]_i$) in the cultured rabbit aortic endothelial cells was recorded by a microfluorimeter with using Fura-2/AM. Hypoxia was evoked to the blood vessels or endothelial cells by eliminating the $O_2$ in the aerating gases in the external solution. Chemical hypoxia was evoked by applying deoxyglucose or $CN^-$. Result: Hypoxia relaxed the precontracted rabbit thoracic aorta that had its endothelium, and the magnitude of the relaxation was gradually increased by repetitive bouts of hypoxia. In contrast, hypoxia-induced relaxation was not evoked in the aorta that was denuded of endothelium. In a bioassay experiment, hypoxia released endothelium-derived relaxing factor (EDRF) and the release was inhibited by L-NAME or the $K^+$ channel blocker tetraethylammonium (TEA). In the cultured endothelial cells, hypoxia augmented the ATP-induced increase of the intracellular $Ca^{2+}$ concentration ($[Ca^{2+}]_i$) and this increase was inhibited by TEA. Furthermore, chemical hypoxia also increased the $Ca^{2+}$ influx. Conclusion: From these results, it can be concluded that hypoxia might induce the release of NO from rabbit aortic endothelial cells by increasing $[[Ca^{2+}]_i$.