• Journal of Life Science
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• v.14 no.2
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• pp.309-314
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• 2004

Cyclic AMP receptor protein (CRP) is involved in the transcriptional regulation of more than 100 genes in E. coli. CRP dimer is converted into active form via the sequential conformation change of cAMP binding pocket, hinge region and HTH DNA binding motif by binding of cAMP. The temperature gradient gel electrophoresis (TGGE) was applied to CRP protein to know whether it was an efficient technique to study the conformational transitions and the thermal stability. TGGE showed the unfolding process of wild-type and S83G CRP proteins with the temperature gradient set from 29 to 71$^{\circ}C$ on nondenaturing polyacrylamide gel. Melting temperature (Tm) was 57$\pm$1 and 55$\pm$1$^{\circ}C$ for wild-type and S83G CRP, respectively in acidic buffer[89.8 mM Glycine and 24 mM Boric acid (pH 5.8)].

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.2
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• pp.201-208
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• 1997

It is becoming increasingly clear that the inflammatory reaction can be ascribed to a complex array of mediators generated and released from activated phagocytes. In this study, the effect of PAF on interleukin-1(IL-1) activity by rat alveolar macrophages(AM) was examined using thymocyte proliferation assay in the supernate of sample obtained after 24 hr culture. When AM were cultured with PAF alone, no change in IL-1 activity was observed. However, the combined addition of PAF and muramyl dipeptide(MDP) or lipopolysaccharide(LPS) to AM cultures markedly enhanced IL-1 activity by 2-3 fold compared with AM cultures with the stimulant alone in a concentration dependent fashion. The peack effect was found at $10^{-8}$ M PAF with MDP and $10^{-14}$ M PAF with LPS. the effect of PAF was also tested in silica, toxic respirable dust, -added AM cultures as well as in the cultures containing bacterial compounds. Although silica did not stimulate the IL-1 activity, PAF could enhance IL-1 activity by 2 fold above the value of the silica-treated AM cultures with the peak response at $10^{-12}$ M PAF. Optimal enhancement of IL-1 activity occured when MDP and PAF were present together at the initiation of the 24 hr AM cultures. Additionaly, the biologically inactive precursor/metabolite of PAF, lyso-PAF failed to induce enhancement of IL-1 activity. When the specific, but structurally different PAF receptor antagonists, BN 52021($10^{-5}$ M) and CV 3988($10^{-5}$ M) was treated 15 min before addition of PAF($10^{-8}$ M) and MDP$(10\;{\mu}g/ml)$ to the AM cultures, it markedly inhibited the enhancement of IL-1 activity induced by PAF. The effects of these PAF antagonists were also observed in LPS$(10\;{\mu}g/ml)$-stimulated cells. Collectively, these data suggest that PAF enhances IL-1 activity by interaction with a specific receptor.

• Korean Journal of Veterinary Research
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• v.29 no.2
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• pp.19-24
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• 1989

To elucidate the physiological characteristics of histamine receptor of the isolated renal artery in dog, effects of various receptor blockers and $Ca^{{+}{+}}$ channel blockers on the contractile responses of histamine were investigated in the isolated renal artery of dog. The results were summarized as follows: 1. Histamine caused the contraction in the isolated renal artery of dog, and the contractile responses increased between the concentration of $5{\times}10^{-6}M$ and $10^{-2}M$ in dose-dependent manner. 2. The contractile response induced by histamine ($10^{-3}M$) was not blocked by pretreatment with atropine ($10^{-6}M$), phentolamine ($10^{-6}M$), propranolol ($10^{-6}M$) or cimetidine ($10^{-6}M$), but was completely blocked by pretreatment with pyrilamine ($10^{-6}M$). 3. The contractility induced by histamine ($10^{-3}M$) was decreased in the $Ca^{{+}{+}}$ free medium. 4. The contractile response induced by histamine ($10^{-3}M$) was markedly inhibited by pretreatment with papaverine ($5{\times}10^{-5}M$) or verapamil ($5{\times}10^{-5}M$). 5. After the pre-contraction induced by norepinephrine ($10^{-7}M$) or prostaglandin $F2{\alpha}$ ($5{\times}10^{-6}M$), the contractile response induced by the additional treatment of histamine ($10^{-3}M$) was markedly increased compared with that of histamine ($10^{-3}M$) alone.

• Archives of Pharmacal Research
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• v.24 no.6
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• pp.613-617
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• 2001

The present study examined the hypothesis that NMDA, AMPA/Kainate, and metabotropic (mGlu) glutamate receptors contribute to a behavioral stimulation induced by activation of dopamine receptors by comparing responses in apomorphine-induced cage climbing behaviors in mice. MK-801, CNQX, and MCPG were served as the NMDA receptor, AMPA/Kainate receptor, and mGlu receptor antagonist, respectively, to elucidate the glutamatergic modulation in apomorphine-induced eopaminergic activation in mice. Drugs were administered intracerebroventricularly (i.c.v.) into the mouse brain 15 min before the apomorphine treatment (2 mg/kg, s.c.). 1.c.v. injection of MK-801 inhibited the apomorphine-induced cage climbing behavior dose-dependently. However, treatments with CNQX and MCPG did not any significant change in apomorphine-induced cage climbing behavior in mice. These results suggest that stimulation of NMDA type of glutamate receptors could contribute to the dopaminergic sti mutation, but not AMPA/Kainate and mGlu type glutamate receptors.

• YAKHAK HOEJI
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• v.39 no.2
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• pp.153-160
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• 1995

Receptor binding study was carried out as an in vitro assay to test the anti-ulcer effect for newly synthesized test compounds(IY-80843 and IY-80845) which were reported to have a strong anti-secretory effect in Shay-ligated rats. The histamine H$_{2}$-receptor fraction was prepared from the membranes of the isolated gastric glands in guinea pigs and $^{3}$H-cimetidine was used as a radioligand. The binding of $^{3}$H-cimetidine to the membranes of the isolated gastric glands was found to be time dependent, saturable and confined to a single population of binding sites with $K_{D}$ value of 0.13$\pm$0.03 $\mu{M}$ and B$_{max}$ value of 52.5$\pm$1.5 pmol/mg. From the competition experiments, both IY-80843 and IY-80845 were shown to have a strong blocking effect against binding of $^{3}$H-cimetidine to the histamine H$_{2}$-receptor. The IC$_{50}$, Ki, and Hill coefficient(nH) values for IY-80843 were 0.18$\pm$0.02 $\mu{M}$, 0.16$\pm$0.02 $\mu{M}$, and 0.97$\pm$0.15, respectively and those values for IY-80845 were 0.27$\pm$0.02 $\mu{M}$, 0.24$\pm$0.02 $\mu{M}$, and 0.82$\pm$0.13, respectively. The results demonstrated that the blocking effects of IY-80843 and IY-80845 were 7 and 5 times stronger than that of cimetidine, respectively. Therefore, the newly synthesized compounds, IY-80843 and IY-80845, appeared to be the highly potent competitive inhibitors of histamine on the H$_{2}$-receptor.

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.6
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• pp.517-527
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• 2020

Layer 2/3 pyramidal neurons (L2/3 PyNs) of the cortex extend their basal dendrites near the soma and as apical dendritic tufts in layer 1, which mainly receive feedforward and feedback inputs, respectively. It is suggested that neuromodulators such as serotonin and acetylcholine may regulate the information flow between brain structures depending on the brain state. However, little is known about the dendritic compartment-specific induction of synaptic transmission in single PyNs. Here, we studied layer-specific serotonergic and cholinergic induction of long-term synaptic plasticity in L2/3 PyNs of the agranular insular cortex, a lateral component of the orbitofrontal cortex. Using FM1-43 dye unloading, we verified that local electrical stimulation to layers 1 (L1) and 3 (L3) activated axon terminals mostly located in L1 and perisomatic area (L2/3). Independent and AMPA receptor-mediated excitatory postsynaptic potential was evoked by local electrical stimulation of either L1 or L3. Application of serotonin (5-HT, 10 μM) induced activity-dependent longterm depression (LTD) in L2/3 but not in L1 inputs. LTD induced by 5-HT was blocked by the 5-HT₂ receptor antagonist ketanserin, an NMDA receptor antagonist and by intracellular Ca²⁺ chelation. The 5-HT₂ receptor agonist α-me-5-HT mimicked the LTD induced by 5-HT. However, the application of carbachol induced muscarinic receptor-dependent LTD in both inputs. The differential layer-specific induction of LTD by neuromodulators might play an important role in information processing mechanism of the prefrontal cortex.

• Tuberculosis and Respiratory Diseases
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• v.74 no.6
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• pp.264-268
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• 2013

Background: Idiopathic pulmonary fibrosis (IPF) is a lethal pulmonary fibrotic disease. In general, the exaggerated activation of the coagulation cascade has been observed during initiation or maintenance of the fibrotic disease. In our recent study, immunohistochemical expression of protease-activated receptor-2 (PAR-2), which plays a key role in coagulation cascade, was observed in surgical specimen of IPF patients, and associated with poor clinical outcome. The aim of this study was to evaluate the overexpression of PAR-2 in inflammatory cells from peripheral blood and bronchoalveolar lavage fluid in IPF patients. Methods: From May 2011 to March 2012, IPF patients and controls were enrolled in Seoul National University Hospital. Peripheral blood and bronchoalveolar lavage fluid were collected for analysis of PAR-2 expression. Flow cytometry and reverse transcription polymerase chain reaction were used for PAR-2 receptor and mRNA assessment. Results: Twelve IPF patients and 14 controls were included in this study. Among them, flow cytometry analysis was conducted from 26 peripheral blood (patient group, 11; control group, 13) and 7 bronchoalveolar lavage fluid (patient group, 5; control group, 2). The expression of PAR-2 receptor was not different between patient and control groups (p=0.074). Among all 24 population, PAR-2 mRNA assessment was performed in 19 persons (patient group, 10; control group, 9). The mRNA expression of PAR-2 was not significant different (p=0.633). Conclusion: In IPF patients, PAR-2 receptor and mRNA expression were not different from control group.

• The Korean Journal of Pharmacology
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• v.17 no.2
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• pp.17-22
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• 1981

In the electrically stimulated guinea-pig ileum, which was incubated in the modified Krebs-Henseleit bicarbonate buffer solution containing various concentrations of electrolytes at $4^{\circ}C$ for 24 hours, the effect of naloxone on the inhibitory action of morphine was investigated. Incubation potentiated the inhibitory action of morphine. In the incubated preperation, the inhibitory action of morphine was potentiated in the $Na^+\;75mM$, and $K^+\;2.9mM$ groups, while that action of morphine was reduced in the $Ca^{++}\;3.6mM,\;Mg^{++}$ free and $Mn{++}\;0.2mM$ groups. Naloxone in incubation media potentiated in the inhibitory action of morphine. In the preparations which were incubated in various concentrations of electrolytes plus naloxone, the action of morphine was reduced in $Na^+\;75mM,\;K^+\;2.9mM$, and $Ca^{++}\;3.6mM$ groups, while that action of morphine was potentiated in $Mg^{++}$free and $Mn{++}\;0.2mM$ groups. Naloxone antagonised those actions of morphine. However, $pA_2$ values for naloxone (index for affinity for antagonist) was not changed. Thus changes in the inhitory action of morphine caused by incubation are probably not the result of changes in the affinity of receptor, but due to the alterations in the events which precede or follow the receptor binding by incubations.

• Toxicological Research
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• v.6 no.1
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• pp.75-88
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• 1990

The characteristics of dopamine uptake, D-1 and D-2 receptors after acute and subacute cocaine administration were determind in striatum from WKY and SHR. Cocaine was administered either acutely (40 mg/kg, s.c.) or twice daily (20 mg/kg, s.c.) for 3 and 7 days in 9-wk old WKY and SHR. Rats were sacrificed 30 min, 2 or 24 h after the single injection and 18 h after the last administration to the subacutely treated group. The changes in dopamine uptake, dopamine uptake sites, D-1 and D-2 receptors were determined using $(^3H)$dopamine, $(^3H)$-GBR-12935, $(^3H)$SCH-23390 and $(^3H)$sulpiride, respectively. In acutely treated rats, significant increases in $V_{max}$of dopamine uptake were observed 30 min after the cocanine injection in both strains without changes in $K_m$ values. The in vitro $IC_{50}$for cocaine was significantly decreased 30 min in WKY and 2 h in SHR. However, that for in vitro GBR-12909 was significantly increased 30 min and 2 h in both strains. Also densities of $(^3H)$-GBR-12935 binding sites were significantly increased 30 min and 2 h without changes in their $K_d$. Significant increases in D-2 receptor density were observed 30 min, 2 or 24 h after acute injection in both strains without changes in their affinities. The density of D-1 receptor was significantly decreased 30 min after the injection in WKY, but not in SHR. In subacutely treated rats, a significant increase in $K_m$ of dopamine uptake was observed in 7-day treated SHR. The in vitro $IC_{50}$fot GBR-12909 was significantly increased in 3-day treated WKY. The density of D-1 receptors was significantly increased in 3- and 7-day treated WKY, but not in SHR. The affinity of both binding sites remained unchanged. The results suggest that cocanine administration alters dopamine uptake, characteristics of dopamine uptake sites and dopamine receptor binding characteristics in rat brain. Furthermore, D-1 and D-2 dopamine receptors appear to be differently regulated.

• Korean Journal of Veterinary Research
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• v.37 no.2
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• pp.331-338
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• 1997

최근 동물의 진통 및 진정을 목적으로 널리 사용되고 있는 imidazole 유도체인 clonidine, medetomidine, etomidate 등의 약물과 xylazine의 효과를 발정정지기의 척출 돼지 자궁근에서 검토하였다. Clonidine($10^{-8}{\sim}10^{-6}M$)이나 medetomidine($10^{-8}{\sim}10^{-6}M$)은 xylazine과 비슷한 정도로 용량의존적인 자궁근의 수축을 일으켰다. Clonidine, medetomidine, xylazine 등의 $EC_{50}$는 각각 24.7nM, 19.9nM, 45.1nM이었다. 그러나 etomidate는 $10^{-6}M$ 미만의 농도에서 반응이 거의 없었으며, $10^{-6}M$ 이상에서 수축반응을 일으켰다. 이들 agonists의 효과는 yohimbine($10^{-8}{\sim}10^{-6}M$), idazoxan($10^{-7}{\sim}10^{-5}M$), tolazoline($10^{-7}{\sim}10^{-5}M$) 등의 ${\alpha}_2-adrenoceptor$ antagonists에 의해서 차단되었으나, ${\alpha}_1-adrenoceptor$ antagonist인 prazosin ($10^{-6}M$)에 의해서는 차단되지 않았다. 또한 $Ca^{2+}-free$ medium이나 verapamil($10^{-5}M$)의 전처치에 의해서 이들 agonist의 효과가 완전히 차단되었다. 결론적으로 발정정지기의 돼지 자궁근에서 clonidine, medetomidine, etomidate, xylazine 등은 ${\alpha}_2-adrenoceptors$의 흥분을 통해 자궁근의 수축을 일으키며, 이 효과는 voltage-dependent $Ca^{2+}$ channels을 통한 extracellular $Ca^{2+}$ influx의 증가에 의한 것으로 추론하였다.