• Korean Journal of Veterinary Research
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• v.40 no.3
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• pp.479-487
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• 2000

Several recent studies demonstrate that receptor-mediated cAMP (adenosine 3',5'-monophosphate) production evokes marked change in magnesium ($Mg^{2+}$) homeostasis. The effects of dimaprit or/and phosphodiesterase (PDE) inhibitors on the $Mg^{2+}$ release from perfused guinea pig heart and collagenase-dispersed myocytes was studied to clarify an association of $H_2-histaminergic$ receptor-mediated $Mg^{2+}$ regulation with intracellular cAMP-degradation system. $Mg^{2+}$ efflux was stimulated in perfused hearts and myocytes by IBMX (3-isobutyl-1-methylxanthine), a calmodulin-sensitive PDE inhibitor, but not by RO 20-1724(4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone) or papaverine, cAMP-specific PDE inhibitors. $Mg^{2+}$ efflux was also be induced by dimaprit, a H-2-agonist. $Mg^{2+}$ effluxes induced by dimaprit were augmented by the presence of the PDE inhibitors. The augmentation of dimaprit-induced $Mg^{2+}$ effluxes by the PDE inhibitors were inhibited by ranitidine, a $H_2-antagonist$, and imipramine, a $Na^{+}-Mg^{2+}$ exchange inhibitor, in perfused hearts and myocytes and were also inhibited by amiloride in perfused hearts. These results suggest that the $H_2$-stimulated $Mg^{2+}$ effluxes from guinea pig heart can be regulated by the cytosolic nonspecific-dependent PDE systems and that it is induced by the $Na^{+}-Mg^{2+}$ exchanger stimulation.

• Biomolecules & Therapeutics
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• v.1 no.2
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• pp.188-195
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• 1993

In order to understand the machanism of action and regulation of ${\beta}$-adrenergic receptor in terms of molecular level, the purification of receptor protein has a fundamental importance. Moreover, species differences among avian, amphibian and mammalian ${\beta}$-adrenergic receptors make it more important to purify mammalian ${\beta}$-adrenergic receptor. Because ${\beta}$-adrenergic receptor is an integral membrane protein, it must be solubilized from the membrane for the purification. The purpose of the present study was to solubilize and characterize the mammalian $\beta$-adrenergic receptor from guinea pig lung in quantities by more efficient and practical method eventually to purify receptor. Guinea pig lung membrane preparation was solubilized by sequential treatment of buffers containing low and high concentration of digitonin which are 0.2 and 1.2% respectively. About 50% of the total receptor pool was released by this double extraction procedure. The $\beta$-adrenoceptors in the digitonin extract were identified using the ${\beta}$-adrenergic antagonist, (-)-[$^3H$]-dihydroalprenolol ([$^3H$]DHA). The solubilized receptor retained all of the essential characteristics of membrane-bound receptor, namely saturability; stereoselectivity; high affinity to ${\beta}$-adrenergic drugs. For the measurement of soluble receptor activity, Sephadex G-50 chromatography method has been widely used. Inspite of its accuracy and wide acceptance, this technique employed troublesome column work which required long time to assay the activity of receptor. We employed another methods to measure receptor activity. When using 0.5% polyethylenimine pretreated GF/B glass fiber filter, filtration technique could be used to measure soluble receptor activity. This technique enabled us to reduce the total amount of time to assay by a factor of 4 as well as to detect soluble receptor. In the present study, we could establish more efficient and practical solubilization method of mammalian $\beta$-adrenergic receptor. The rapidity and high yield of this solubilization scheme, together with the favorable recovery of the receptor activity, are significant steps toward the ultimate purification of the mammalian $\beta$-adrenergic receptor. The result of this study together with more convenient purification method could provide large amount of purified receptor with ease for various research purposes.

• The Korean Journal of Pharmacology
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• v.26 no.2
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• pp.167-176
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• 1990

In the present study, we examined the effects of tamoxifen and LY117018 on various parameters for the estrogenic actions in order to understand the mechanism by which tamoxifen and LY117018 act on the uterine cells in 21-23 day old immature rats. Tamoxifen and LY117018 stimulated uterine weight and uterine contents of DNA, protein, and peroxidase activity in the absence of estradiol while inhibited above parameters in the presence of estradiol. Both cytosolic and nuclear progesterone receptors were increased by the treatment of tamoxifen and LY117018 as well as estradiol, but estradiol-induced increase in the progesterone receptors were reduced by the treatment of antiestrogens. These effects were enhanced by the multiple injections of antiestrogens. It seemed that tamoxifen was more agonistic than LY117018 but less antagonistic than LY117018, judged by their effects on various parameters for the estrogenic action. The affinities of estradiol, tamoxifen, and LY117018 for the estrogen receptor were $0.17{\pm}0.01nM(100%)$, $1.10{\pm}0.01nM(6.3%)$, and $0.23{\pm}0.01nM(77%)$, respectively. Furthermore, LY117018 was the competitive ligand for the estrogen receptor in dose-related manner but tamoxifen was not. Following estradiol treatment, nuclear estrogen receptor was sharply increased by 1 h, reaching the maximum by 16 h, while tamoxifen and LY117018 slightly increased nuclear estrogen receptor by 1 h and then decreased thereafter. It is therefore concluded that LY117018 is a competitive antagonist for the estrogen receptor with less estrogenic activity, compared to tamoxifen with low affinity to the estrogen receptor, and tamoxifen may act through other binding site than the estrogen receptor.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.1
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• pp.1-12
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• 1997

As it has been reported that the depolarization induced acetylcholine (ACh) release is modulated by activation of presynaptic $A_1$ adenosine heteroreceptor and various evidence suggest that indicate the $A_2$ adenosine receptor is present in the striatum, this study was undertaken to delineate the role of adenosine receptors on the striatal ACh release. Slices from the rat striatum were equilibrated with $[^3H]$choline and then the release amount of the labelled product, $[^3H]$ACh, which was evoked by electrical stimulation (rectangular pulses, 3 Hz, 2 ms, 24 mA, $5\;Vcm^{-1}$, 2 min), was measured, and the influence of various agents on the evoked tritium outflow was investigated. And also, quantitative receptor autoradiography and drug-receptor binding assay were performed in order to confirm the presence and characteristics of $A_1$ and $A_2$ adenosine receptors in the rat striatum. Adenosine $(10{sim}100\;{mu}M)$ and $N^6$-cyclopentyladenosine (CPA, $1{sim}100\;{mu}M)$ decreased the $[^3H]$ACh release in a dose-dependent manner without changing the basal rate of release in the rat striatum. The reducing effects of ACh release by adenosine and CPA were abolished by 8-cyclopentyl-1,3-dipropy-Ixanthine (DPCPX, 2 ${mu}M$), a selective $A_1$, adenosine receptor antagonist, treatment. The effect of adenosine was potentiated markedly by 3,7-dimethyl-1-propargylxanthine (DMPX, 10 ${mu}M$), a specific $A_2$ adenosine receptor antagonist. 2-P-(2-carboxyethyl)phenethylamimo-5'-N- ethylcarboxamidoadenosine hydrochloride (CGS-21680C), in concentrations ranging from 0.01 to 10 ${mu}M$, a recently introduced potent $A_2$ adenosine receptor agonist, increased the $[^3H]$ACh release in a dose related fashion without changing the basal rate of release. These effects were completely abolished by DMPX $(10\;{mu}M)$. In autoradiograrhy experiments, $[^3H]$2-chloro-$N^6$-cyclopentyladenosine ($[^3H]$ CCPA) bindings were highly localized in the hippocampus and the cerebral cortex. Additionally, lower levels of binding were found in the striatum. However, $[^3H]$CGS-21680C bindings were highly localized in the striatal region with the greatest density of binding found in the caudate nucleus and putamen. Lower levels of binding were also found in the nucleus accumbens and olfactory tubercle. In drug-receptor binding assay, binding of $[^3H]$ CCPA to $A_1$ adenosine receptors of rat striatal membranes was inhibited by CPA ($K_i$ = 1.6 nM) and N-ethylcarboxamidoadenosine (NECA, $K_i$ = 12.9 nM), but not by CGS-21680C ($K_i$ = 2609.2 nM) and DMPX ($K_i$ = 19,386 nM). In contrast, $[^3H]$CGS-21680C binding to $A_2$ denosine receptors was inhibited by CGS-21680C ($K_i$ = 47.6 nM) and NECA ($K_i$ = 44.9 nM), but not by CPA ($K_i$ = 2099.2 nM) and DPCPX ($K_i$ = 19,207 nM). The results presented here suggest that both types of $A_1$ and $A_2$ adenosine heteroreceptors exist and play an important role in ACh release in the rat striatal cholinergic neurons.

• Journal of Chest Surgery
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• v.30 no.12
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• pp.1251-1253
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• 1997

Gastrointestinal complications, especially duodenal complication after cardiopulmonary bypass are rare, but often fatal. We experienced 1 case of duodenal ulcer bleeding and 2 cases of duodenal ulcer perforation developing after cardiopulmonary bypass from August 1994 to April 1996. In the case of duodenal ulcer bleeding, palpitation, dizziness, tachycardia and melena were the clues leading to diagnosis, and in the cases of perforation, abdominal distension with pain, tachycardia, hypotension, oliguria were the clues. Duodenal perforations were diagnosed by abdominal paracentesis. The patient with duodenal bleeding was treated by H-2 receptor antagonist, antacids and transfusion. And emergency laparotomy was required for the patients with duodenal perforation. In addition to ulcer prophylaxis including H-2 receptor antagonist and antacids, a high index of suspicion and timely surgery are necessary for early diagnosis and appropriate treatment of duodenal complication developing af er cardiopulmonary bypass.

• Archives of Pharmacal Research
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• v.28 no.8
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• pp.930-935
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• 2005

We have investigated the effects of relatively high concentration of carbachol (CCh), an agonist of muscarinic acetylcholine receptor (mAChR), on cardiac automaticity in mouse heart. Action potentials from automatically beating right atria of mice were measured with conventional microelectrodes. When atria were treated with $100{\mu}M$ CCh, atrial beating was immediately arrested and diastolic membrane potential (DMP) was depolarized. After exposure of the atria to CCh for $\~4 min$, action potentials were regenerated. The regenerated action potentials had lower frequency and shorter duration when compared with the control. When atria were pre-exposed to pirenzepine $(1{\mu}M)$, an $M_1$ mAChR antagonist, there was complete inhibition of CCh-induced depolarization of DMP and regeneration of action potentials. Pre-exposure to AFDX-116 (11 ({2-[(diethylamino)-methyl]-1-piperidyl}acetyl)-5, 11-dihydro-6H-pyridol[2,3-b][1,4] benzodiazepine-6-one base, $1{\mu}M$), an $M_2$ mAChR antagonist, failed to block CCh-induced arrest of the beating. However, prolonged exposure to CCh elicited gradual depolarization of DMP and slight acceleration in beating rate. Our data indicate that high concentration of CCh depolarizes membrane potential and recovers right atrial automaticity via $M_1$ mAChR, providing functional evidence for the role of $M_1$ mAChR in the atrial myocytes.

• Archives of Pharmacal Research
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• v.14 no.2
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• pp.181-187
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• 1991

The muscarinic antagonist 1-[benzilic 4, 4'-$[^3H]$ QUINUCLIDINYL BENZILATE $([^3H]$ QNB) bound to a single class of muscarinic receptors with high affinity in rabbit ileal membranes. The $K_D\;and\;B_{ max}$ values for $([^3H]$ QNB calculated from analysis of saturation isotherms were 52.5 pM AND 154 fmol/mg, respectively. Chlopheniramine (CHP), histamine $H_1$ blocker, increased $K_D$ vlue for $([^3H]$QNB without affecting the binding site concentrations and Hill coefficient. The $K_i$ value of CHP for inhibition of $([^3H]$QNB binding in ileal membranes was 1.44\mu{M}$ and the pseudo-Hill coefficient for CHP was close to unit. In the functional assay carbachol, muscarinic agonist, increased the contractile force of ileum with $ED_{50}$ value of $0.11\mu{M}$. CHP caused the rightward shift of the dose-response curve to carbachol. The $pA_2$ value of CHP determined from Schild analysis of carbacholinduced contraction was 5.77 and the slope was unity indicating competitive antagonism with carbachol. The dissociation constant $(K_i)$ of CHP obtained in competitive experiments with $([^3H]$ QNB was similar to the $K_A$ value (1.69 \mu{M)}$ of CHP as inhibitor of carbachol induced contraction in rabbit ileum. This result suggest that the binding of $H_i$ blocker. CHP, vs $([^3H]$QNB to muscarinic receptors in ileal membranes represents an interaction with a receptor of physiological relevance.

• Tuberculosis and Respiratory Diseases
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• v.52 no.3
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• pp.219-229
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• 2002

Background : Sepsis-induced acute lung injury (ALI) is caused by many cellular and humoral mediators induced by an endotoxin. Histamine, which is widely distributed in the lungs and has been considered as an important mediator of sepsis. It increases P-selectin expression on the endothelial cell surfaces and induces IL-8 secretion. Therefore, an endotoxin-induced histamine may be related to neutrophil-mediated ALI by inducing the migration and activation of neutrophils in the lung tissue. However, the role of endogenous histamine in endotoxin ALI has not been clarified. The purpose of this study was to investigate how endotoxin-induced ALI is influenced by endogenous histamine and to identify the possible mechanism of action. Materials and Methods : The study consisted of 4 groups using Sprague-Dawley rats : 1) control group, where the rats were infused intratracheally by normal saline, 2) an endotoxin group, where lipopolysaccharide (LPS) was administered intratracheally 3) the $H_2$ receptor antagonist-treated group ($H_2$ group) and 4) the $H_1$ receptor antagonist-treated group ($H_1$ group), where $H_2$-receptor blocker (ranitidine) and $H_1$-receptor blocker(pyrilamine) were co-treated intravenously with the intratracheal administration of an endotoxin. The lung leak index using $I^{125}$-BSA, the total protein and LDH concentration in the lung lavage fluid, myeloperoxidase(MPO) activity in the lung tissue, the pathologic score and the total number of neutrophils, TNF-$\alpha$, IL-$1{\beta}$ and IL-10 in lung lavage (BAL) fluid were measured in each group as the indices of lung injury. Results : Compared to the control group, the endotoxin group exhibited significant increases in all lung injury indices. Significant reductions in the endotoxin-mediated increases in lung leak index (p<0.05) were observed in both the $H_1$ and $H_2$ groups. In addition the total protein (p<0.05) and LDH concentration (p<0.05) in the BAL fluid were also lower in the $H_2$ group compared to the endotoxin group. However, there was no change in the MPO activity in the lung tissue, the pathologic score and the total number of neutrophils in the BAL fluid in both the $H_2$ and $H_1$ groups compared to the endotoxin group. The increases in TNF-$\alpha$ IL-$1{\beta}$ and IL-10 concentrations in the BAL fluid observed in the endotoxin group were not reduced in the $H_2$ and $H_1$ groups. Conclusion : Antihistamine attenuated the enhanced alveolar-capillary permeability induced by the endotoxin via the $H_2$ receptor. However the attenuating mechanism may not be related to the pathogenesis of neutrophil dependent lung injury.

• Journal of Oriental Neuropsychiatry
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• v.15 no.1
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• pp.77-86
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• 2004

Objective : This study was performed to investigate the agonistic activity of Chunmajeongal-tang extract to the $GABA_A/benzodiazepine$ receptor complex. Methods : Male mice and Sprague-Dawley rats were used for this experiment. Chunmajeongal-tang Prescription was extracted with 80% methanol, evaporated in vacuo and dried with freeze dryer. The agonistic activity to the GABA/ benzodiazepine receptor complex and GABA transaminase activity were measured in vitro. Results : Chunmajeongal-tang extract inhibited dose-dependently the binding of [3H]Ro15-1788, an antagonist on GABA/benzodiazepine receptor complex, in rat cerebral cortices, showing $82.4{\pm}4.12%$ inhibition at a dose of 5.0 mg/kg. This extract inhibited dose-dependently the binding of [3H]flunitrazepam, an agonist on GABA/benzodiazepine receptor complex, in rat cerebral cortices, showing $5.6{\pm}1.24%$ inhibition. Furthermore, Chunmajeongal-tang extract inhibited the binding of [3H]flunitrazepam in the presence of GABA/NaCI with $13.2{\pm}0.44%$ inhibition, its inhibitory effect exhibited a positive GABA shift, which means that this extract activates a GABAergic neurotransmission.

• BMB Reports
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• v.48 no.8
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• pp.479-484
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• 2015

In this study, we report that one of the antimicrobial peptides scolopendrasin VII, derived from Scolopendra subspinipes mutilans, stimulates actin polymerization and the subsequent chemotactic migration of macrophages through the activation of ERK and protein kinase B (Akt) activity. The scolopendrasin VII-induced chemotactic migration of macrophages is inhibited by the formyl peptide receptor 1 (FPR1) antagonist cyclosporine H. We also found that scolopendrasin VII stimulate the chemotactic migration of FPR1-transfected RBL-2H3 cells, but not that of vector-transfected cells; moreover, scolopendrasin VII directly binds to FPR1. Our findings therefore suggest that the antimicrobial peptide scolopendrasin VII, derived from Scolopendra subspinipes mutilans, stimulates macrophages, resulting in chemotactic migration via FPR1 signaling, and the peptide can be useful in the study of FPR1-related biological responses. [BMB Reports 2015; 48(8): 479-484]