• 제목/요약/키워드: Desensitization

검색결과 121건 처리시간 0.025초

Involvement of phospholipase $A_2$ in ATP-induced mucin release from cultured Hamster Tracheal Surface Epithelial cells

  • Jo, M.;Ko, K.H.;Kim, K.C.
    • 한국응용약물학회:학술대회논문집
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    • 한국응용약물학회 1996년도 춘계학술대회
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    • pp.219-219
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    • 1996
  • Mucin release from hamster tracheal surface epithelial(HTSE) cells can be stimulated by extracellular ATP via activation of P$_2$ purinoceptors located on the cell surface which appears to be coupled to phospholipase C via G proteins. However, our preliminary data indicate that the ATP-induced mucin release involves, in part, activation of PKC, but not an increase in the intracellular Ca++ level, suggesting the presence of another pathway which is separate from the PLC-PKC pathway, In this study, we intended to confirm the previous observation and subsequently identify an additional mechanism. Confluent HTSE cells were metabolically labeled with either $^3$H-glucosamine or $^3$H-arachidonic acid(AA), and release of either $^3$H-mucin or $^3$H-AA was quantified following various treatments. $^3$H-mucin was assayed using the sepharose CL-4B gel-filtration method, whereas $^3$H-AA liberation was measured by counting $^3$H-radioactivity in the chase medium. We found that: (1)Desensitization of PKC by pretreatment with PMA completely abolished the mucin releasing effect of PMA but partially inhibited the ATP-induced mucin release; (2) ATP increases release of $^3$H-AA in a dose-dependent fashion; (3) mepacrine, an inhibitor of PLA$_2$, attenuates ATP-induced mucin release in a dose-dependent fashion. These results confirm our previous notion that the PLC-PKC pathway is responsible, in part, for ATP-induced mucin release. Furthermore, activation of PLA$_2$ appears to be an additional pathway which is involved in ATP-induced mucin release.

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Enhanced Coupling of $M_1$ Muscarinic Receptors to Activation of Phospholipase C upon Mutation of a Transposed Amino Acid Triplet Repeat

  • Lee, Seok-Yong;Sung, Ki-Wug;Kim, Ok-Nyu;Lee, Sang-Bok
    • The Korean Journal of Physiology and Pharmacology
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    • 제1권1호
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    • pp.19-25
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    • 1997
  • The C-terminus ends of the second putative transmembrane domains of both $M_1$ and $M_2$ muscarinic receptors contain a triplet of amino acid residues consisting of leucine (L), tyrosine (Y) and threonine (T). This triplet is repeated as LYT-TYL in $M_1$ receptors at the interface between the second transmembrane domain and the first extracellular loop. Interestingly, however, it is repeated in a transposedfashion (LYT-LYT) in the sequence of $M_2$ receptors. In our previous work, we investigated the possible significance of this unique sequence diversity for determining the distinct differential receptor function at the two receptor subtypes. However, we found mutation of the LYTTYL sequence of $M_1$ receptors to the corresponding $M_2$ receptor LYTLYT sequence demonstrated markedly enhanced the stimulation of phosphoinositide (PI) hydrolysis by carbachol without a change in its coupling to increased cyclic AMP formation. In this work, thus, the enhanced stimulation of PI hydrolysis in the LYTLYT $M_1$ receptor mutant was further investigated. The stimulation of PI hydrolysis by carbachol was enhanced in the mutant $M_1$ receptor, and this change was not due to alterations in the rate of receptor desensitization or sequestration. The observed larger response to carbachol at mutant $M_1$ receptors was also not due to an artifact resulting from selection of CHO cells which express higher levels of G-proteins or phospholipase C. Our data suggest that although the LYTTYL sequence in $M_1$ muscarinic receptors is not involved in determining receptor pharmacology, mutation of the sequence enhanced the coupling of $M_1$ receptors to the stimulation of phospholipase C.

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Ca2+/calmodulin-dependent regulation of polycystic kidney disease 2-like-1 by binding at C-terminal domain

  • Baik, Julia Young;Park, Eunice Yon June;So, Insuk
    • The Korean Journal of Physiology and Pharmacology
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    • 제24권3호
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    • pp.277-286
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    • 2020
  • Polycystic kidney disease 2-like-1 (PKD2L1), also known as polycystin-L or TRPP3, is a non-selective cation channel that regulates intracellular calcium concentration. Calmodulin (CaM) is a calcium binding protein, consisting of N-lobe and C-lobe with two calcium binding EF-hands in each lobe. In previous study, we confirmed that CaM is associated with desensitization of PKD2L1 and that CaM N-lobe and PKD2L1 EF-hand specifically are involved. However, the CaM-binding domain (CaMBD) and its inhibitory mechanism of PKD2L1 have not been identified. In order to identify CaM-binding anchor residue of PKD2L1, single mutants of putative CaMBD and EF-hand deletion mutants were generated. The current changes of the mutants were recorded with whole-cell patch clamp. The calmidazolium (CMZ), a calmodulin inhibitor, was used under different concentrations of intracellular. Among the mutants that showed similar or higher basal currents with that of the PKD2L1 wild type, L593A showed little change in current induced by CMZ. Co-expression of L593A with CaM attenuated the inhibitory effect of PKD2L1 by CaM. In the previous study it was inferred that CaM C-lobe inhibits channels by binding to PKD2L1 at 16 nM calcium concentration and CaM N-lobe at 100 nM. Based on the results at 16 nM calcium concentration condition, this study suggests that CaM C-lobe binds to Leu-593, which can be a CaM C-lobe anchor residue, to regulate channel activity. Taken together, our results provide a model for the regulation of PKD2L1 channel activity by CaM.

Effects of L-trans-pyrrolidine-2,4-dicarboxylate, a Glutamate Uptake Inhibitor, on NMDA Receptor-mediated Calcium Influx and Extracellular Glutamate Accumulation in Cultured Cerebellar Granule Neurons

  • Oh, Seikwan;Shin, Chang-Sik;Patrick-P. McCaslin;Seong, Yeon-Hee;Kim, Hack-Seang
    • Archives of Pharmacal Research
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    • 제20권1호
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    • pp.7-12
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    • 1997
  • Glutamate uptake inhibitor, L-trans-pyrrolidine-2, 4-dicarboxylate (PDC, $20{\mu}M$) elevated basal and N-methyl-D-aspartate (NMDA, $100{\mu}M$)-induced extracellular glutamate accumulation, while it did not augment kainate $100{\mu}M$-induced glutamate accumulation in cultured cerebellar granule neurons. However, pretreatment with PDC for 1 h significantly reduced NMDA-induced glutamate accumulation, but did not affect kainate-induced response. Pretreatment with glutamate $(5{\mu}M)$ for 1 h also reduced NMDA-induced glutamate accumulation, but did not kainate-induced response. Upon a brief application (3-10 min), PDC did neither induce elevation of intracellular calcium concentration $([Ca^{2+}]_i)$ nor modulate NMDA-indLiced $[Ca^{2+}]_1$ elevation. Pretreatment with PDC for 1 h reduced NMDA-induced $[Ca^{2+}]_1$ elevation, but it did not reduce kainate-induced $[Ca^{2+}]_1$ elevation. These results suggest that glutamate concentration in synaptic clefts of neurana cells is increased by prolonged exposure (1 h) of the cells to PDC, and the accumulated glutamate subsequently induces selective desensitization of NMDA receptor.

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생애주기에 따른 스트레스 관리 프로그램에 대한 고찰 -1993년부터 1996년까지의 외국문헌을 중심으로- (Literature Review on the Stress Management Programs throughout Life - span: By foreign research for 1993-1996)

  • 윤손녕;최정숙;이경숙
    • 지역사회간호학회지
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    • 제8권2호
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    • pp.178-196
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    • 1997
  • The purpose of this study is to identify the kind, the frequency, and the type of Stress Management Program(SMPs) throughout life-span used foreign, recent research. The period of this study was from July 1 to Dec. 10, 1997. The data were collected through Medline using two concepts: stress management programs and life-span. The number of these research were 106 and thirty-one experimental researches that were tested the effectiveness of SMPs throughout life span were selected. The data were analysed by the kind, frequency, and life-span. The results were as follows: 1. The kind and frequency of SMP : The total number of the kind of SMP were twenty-two. The most used SMP was relaxation therapy, 22 out of 31. The second biofeedback was 10, the third, cognitive behavior program was 9, the fourth, nutrition and diet, and education were 7. The others were coping skill(4), cognitive therapy(4), breathing(4), imagery(3), autogenic training(3), sleep and rest(2), meditation(2), information(2), desensitization(2), hypnosis(2), behavior therapy(1), time management (1), visualization(I), yoga(I), diversion(1), and problem solving skill. 2. Throughout life-span: Most SMPs were applied to adolescents, young adults, and middle-adults. Other subjects could not be found under the schooler. 3. The type of SMPs : 28(90.3%) out of 31 research used combined-SMP : two-combined SMP, 5: three-combined SMP, twelve: four-combined SMP, seven: five-combined SMP. 4. Afterward, further study such as meta-analysis are needed in order to identify effective ness of the SMPs.

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정신치료와 신경생물학적 연구결과의 관계 (The Relationship between Psychotherapy and Neurobiological Findings)

  • 오현영;박용천
    • 생물정신의학
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    • 제19권1호
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    • pp.1-8
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    • 2012
  • The mechanism of psychotherapy is explained by the recent developments in neuroscience and neuroimaging. The purpose of this study is to understand the nature of psychotherapy and to discuss the future of psychotherapy improvement with the help of advances of the neurobiological findings in psychotherapy. For this study, we investigated a wide range of materials. We searched for various researches on psychotherapy, brain, and neurobiology. In addition to the conventional psychodynamic psychotherapy, we investigated research findings on cognitive behavioral therapy, interpersonal psychotherapy and eye movement desensitization and reprocessing (EMDR). Moreover, based on the actual experiences of treating patients, we speculated the neurobiological mechanisms of the process and results of psychotherapy. With the development of neuroscience, we are now able to understand the personal consciousness, unconsciousness and developmental process. Also subdividing the disease is made possible. Personalized treatment has become available, and we are able to predict the prognosis of patients. Our memories are composed by implicit memory and explicit memory. By psychotherapy, we can consciously remember explicit memory, and it becomes easier to explore implicit memory through free association. Through psychotherapy, we will also be able to learn the effect of acquired environment and experience. Psychotherapy is able to correct human behaviors by modifying the memories. Through the regulation of emotions, it becomes possible to modify the memories and correct the behaviors. In this process, doctor-patient relationship is the main factor which cause positive treatment effects. Furthermore imagination therapy or unconscious, non-verbal stimuli could bring about positive treatment effects. Now psychotherapy could be explained and studied by neuroscientific researches. In this sense, we could provide the direction of future advances in neuroscience by the neurobiological understanding of psychotherapy.

Identification of Amino Acid Residues Involved in Feedback Inhibition of the Anthranilate Synthase in Escherichia coli

  • Kwak, Joon-Hyeok;Hong, Kwang-Won;Lee, Sung-Haeng;Hong, Jin-Han;Lee, Se-Yong
    • BMB Reports
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    • 제32권1호
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    • pp.20-24
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    • 1999
  • The first step of the branch pathway in tryptophan biosynthesis is catalyzed by anthranilate synthase, which is subjected to feedback inhibition by the end product of the pathway. The $trpE^{FBR}$ gene from a mutant Escherichia coli strain coding for anthranilate synthase that was insensitive to feedback inhibition by tryptophan has been cloned. To identify the amino acid changes involved in the feedback regulation of anthranilate synthase, the nucleotide sequence of the mutant $trpE^{FBR}$ gene was determined. Sequence analysis of the $trpE^{FBR}$ gene revealed that four bases were changed in the structural gene while alteration was not found in the 5' control region. Among these base changes, only two base substitutions caused the alterations in amino acid sequences. From the results of restriction fragment exchange mapping, the 61st nucleotide, C to A substitution, that changed $Pro^{21}{\rightarrow}Ser$ was identified as the cause of the desensitization to feedback inhibition by tryptophan. Additional feedback-resistant enzymes of the E. coli anthranilate synthases were constructed by site-directed mutagenesis to examine the effect of the $Ser^{40}\;{\rightarrow}\;Arg^{40}$ change found in the $trpE^{FBR}$ gene of Brevibacterium lactofermentum. From the feedback inhibition analysis, the $Pro^{21}{\rightarrow}Ser$ and $Ser^{40}{\rightarrow}Arg$ mutants maintained about 50% and 90% of their maximal activities, respectively, even at the extreme concentration of 10 mM tryptophan. From these results, we suggest that the $Pro^{21}$ and $Ser^{40}$ residues are involved in the tryptophan binding in the E. coli enzyme.

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색소흡착산화아연에 대한 표면광기전력의 분광학적 연구 (Surface Photovoltage Spectroscopy on Dyed Zinc Oxide)

  • 김영순;성용길
    • 대한화학회지
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    • 제28권4호
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    • pp.251-258
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    • 1984
  • 색소를 흡착시킨 산화아연의 표면상태를 광기전력측정법을 이용하여 색소증감기구 및 바인더(binder)효과에 대한 연구를 수행하였다. 산화아연의 에너지트랩준위는 1.12eV이며, 색소흡착에 의해 0.99eV로 에너지준위가 낮아짐을 알았다. 바인더효과는 표면광기전력의 효율을 커지게 하나 에너지트랩준위에는 변화를 주지 않는다. 또한 색소증감기구로 흡착력이 강한 산형색소는 전자 이동(electron transfer)이며, 산화아연 고유흡수광에 減感작용이 있는 나트륨염형색소는 에너지이동(energy transfer)로써 추측된다. 근적외부인 1,100~1,350nm에 걸쳐 광기전력감도가 나타나므로 적외선에 의한 전자사진용 畵像材料로서 가능성을 제시하였다.

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알레르기 치료를 이용한 비용증을 동반한 부비동염의 치험 2례 (Two Cured Cases of Nasal Polyposis Combiend with Chronic Sinusitis by Allergy Therapy)

  • 박정열;임원호;이영환;임현준;김형곤
    • 대한기관식도과학회:학술대회논문집
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    • 대한기관식도과학회 1982년도 제16차 학술대회연제순서 및 초록
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    • pp.16.3-17
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    • 1982
  • E. N. T. Clinic에 내원하는 환자중 nasal symptoms을 호소하는 환자의 높은 비율에서 알레르기 질환이 있는 것을 느끼게 되며 특히 nasal cavity내에 오는 질환의 원인 중 알레르기가 놀라울 정도로 많은 것을 생각하면 이비인후과 영역에서의 알레르기에 대한 관심도 높다고 하겠읍니다. 일반적으로 비용증, 만성비염. 만성부비동염의 치료 방법으로는 약물요법과 수술요법을 병행하여 시행하는데 치료후 증상이 호전되다가 다시 계속적인 치료전의 증상이 재발되는 경우를 흔히 경험하게 된다. 특히 비용증 환자의 치료에서는 높은율의 재발을 경험하게 되는데 nasal symptoms을 일으키는 질환의 많은 원인이 allergy 라는데 착안하여 allegy symptoms은 호소하지 않았으나 비용증을 동반한 만성부비동염 환자에 수술 및 일반치료를 시행하였으나 얼마후 증상이 재현되어 Rinkels technique의 allergy test를 시행 하였다. 특정한 allergen에 양성을 보이지는 않았으나 일반적으로 nasal allergy의 많은 원인이 되는 House dust와 Mold groups의 allergen을 이용 (#2 ∼ #3 Solution)하여 계속적인 Desensitization을 시행함으로서 근치에 가까운 효과를 얻었기에 문헌고찰과 함께 보고하는 바이며 이러한 환자들에게 계속적인 allergy test상 양성반응을 보이지 않더라도 위의 방법을 적용하여 치료한 결과를 추후 발표드릴 것을 약속드립니다.

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Tricyclic antidepressant amitriptyline inhibits 5-hydroxytryptamine 3 receptor currents in NCB-20 cells

  • Park, Yong Soo;Myeong, Seok Ho;Kim, In-Beom;Sung, Ki-Wug
    • The Korean Journal of Physiology and Pharmacology
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    • 제22권5호
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    • pp.585-595
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    • 2018
  • Amitriptyline, a tricyclic antidepressant, is commonly used to treat depression and neuropathic pain, but its mechanism is still unclear. We tested the effect of amitriptyline on 5-hydroxytryptamine 3 ($5-HT_3$) receptor currents and studied its blocking mechanism because the clinical applications of amitriptyline overlapped with $5-HT_3$ receptor therapeutic potentials. Using a whole-cell voltage clamp method, we recorded the currents of the $5-HT_3$ receptor when 5-HT was applied alone or co-applied with amitriptyline in cultured NCB-20 neuroblastoma cells known to express $5-HT_3$ receptors. To elucidate the mechanism of amitriptyline, we simulated the $5-HT_3$ receptor currents using Berkeley $Madonna^{(R)}$ software and calculated the rate constants of the agonist binding and receptor transition steps. The $5-HT_3$ receptor currents were inhibited by amitriptyline in a concentration-dependent, voltage-independent manner, and a competitive mode. Amitriptyline accelerated the desensitization of the $5-HT_3$ receptor. When amitriptyline was applied before 5-HT treatment, the currents rose slowly until the end of 5-HT treatment. When amitriptyline was co-applied with 5-HT, currents rose and decayed rapidly. Peak current amplitudes were decreased in both applications. All macroscopic currents recorded in whole cell voltage clamping experiments were reproduced by simulation and the changes of rate constants by amitriptyline were correlated with macroscopic current recording data. These results suggest that amitriptyline blocks the $5-HT_3$ receptor by close and open state blocking mechanisms, in a competitive manner. We could expand an understanding of pharmacological mechanisms of amitriptyline related to the modulation of a $5-HT_3$ receptor, a potential target of neurologic and psychiatric diseases through this study.