• Title/Summary/Keyword: $AT_{1}$receptor

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Signaling Pathway of Lysophosphatidic Acid-Induced Contraction in Feline Esophageal Smooth Muscle Cells

  • Nam, Yun Sung;Suh, Jung Sook;Song, Hyun Ju;Sohn, Uy Dong
    • The Korean Journal of Physiology and Pharmacology
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    • v.17 no.2
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    • pp.139-147
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    • 2013
  • Lysolipids such as LPA, S1P and SPC have diverse biological activities including cell proliferation, differentiation, and migration. We investigated signaling pathways of LPA-induced contraction in feline esophageal smooth muscle cells. We used freshly isolated smooth muscle cells and permeabilized cells from cat esophagus to measure the length of cells. Maximal contraction occurred at $10^{-6}M$ and the response peaked at 30s. To identify LPA receptor subtypes in cells, western blot analysis was performed with antibodies to LPA receptor subtypes. LPA1 and LPA3 receptor were detected at 50 kDa and 44 kDa. LPA-induced contraction was almost completely blocked by LPA receptor (1/3) antagonist KI16425. Pertussis toxin (PTX) inhibited the contraction induced by LPA, suggesting that the contraction is mediated by a PTX-sensitive G protein. Phospholipase C (PLC) inhibitors U73122 and neomycin, and protein kinase C (PKC) inhibitor GF109203X also reduced the contraction. The PKC-mediated contraction may be isozyme-specific since only $PKC{\varepsilon}$ antibody inhibited the contraction. MEK inhibitor PD98059 and JNK inhibitor SP600125 blocked the contraction. However, there is no synergistic effect of PKC and MAPK on the LPA-induced contraction. In addition, RhoA inhibitor C3 exoenzyme and ROCK inhibitor Y27632 significantly, but not completely, reduced the contraction. The present study demonstrated that LPA-induced contraction seems to be mediated by LPA receptors (1/3), coupled to PTX-sensitive G protein, resulting in activation of PLC, PKC-${\varepsilon}$ pathway, which subsequently mediates activation of ERK and JNK. The data also suggest that RhoA/ROCK are involved in the LPA-induced contraction.

Mitochondrial tumor suppressor 1 is a target of AT-rich interactive domain 1A and progesterone receptor in the murine uterus

  • Chang, Hye Jin;Teasley, Hanna E.;Yoo, Jung-Yoon;Kim, Tae Hoon;Jeong, Jae-Wook
    • Asian-Australasian Journal of Animal Sciences
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    • v.31 no.8
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    • pp.1176-1182
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    • 2018
  • Objective: Progesterone receptor (PGR) and AT-rich interactive domain 1A (ARID1A) have important roles in the establishment and maintenance of pregnancy in the uterus. In present studies, we examined the expression of mitochondrial tumor suppressor 1 (MTUS1) in the murine uterus during early pregnancy as well as in response to ovarian steroid hormone treatment. Methods: We performed quantitative reverse transcription polymerase chain reaction and immunohistochemistry analysis to investigate the regulation of MTUS1 by ARID1A and determined expression patterns of MTUS1 in the uterus during early pregnancy. Results: The expression of MTUS1 was detected on day 0.5 of gestation (GD 0.5) and then gradually increased until GD 3.5 in the luminal and glandular epithelium. However, the expression of MTUS1 was significantly reduced in the uterine epithelial cells of $Pgr^{cre/+}Arid1a^{f/f}$ and Pgr knockout (PRKO) mice at GD 3.5. Furthermore, MTUS1 expression was remarkably induced after P4 treatment in the luminal and glandular epithelium of the wild-type mice. However, the induction of MTUS1 expression was not detected in uteri of $Pgr^{cre/+}Arid1a^{f/f}$ or PRKO mice treated with P4. Conclusion: These results suggest that MTUS1 is a novel target gene by ARID1A and PGR in the uterine epithelial cells.

Responsiveness of Pregnant Rat Uterus to Oxytocin (임신쥐에 대한 옥시토신의 반응)

  • Bai, Y.H.;Cho, C.;Pak, S.C.
    • Korean Journal of Animal Reproduction
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    • v.22 no.1
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    • pp.61-66
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    • 1998
  • In vitro contractile response of the uterus in the pregnant rat to oxytocin increases with advancing gestation. This increase coincides with an increase in uterine oxytocin receptor number. However, in vitro the change in uterine contractile response of the pregnant uterus to oxytocin with advancing gestation is not clear. The purpose of the present study was to find out that the uterine response in vitro to oxytocin changes as delivery a, pp.oaches. Secondly, to determine if the incubation of uterine tissue in vitro altered the uterine oxytocin receptor number and affinity and thus explain the ambiguity between the in vitro and in vitro results. The studies were performed on rats at days 15, 20 and 21 or pregnancy. In vitro the uterine contractile response to oxytocin was sgreater (P<0.05) at day 21 compared to days 15 and 20 (Emax : 724.8 88.9, 130.0 81.5 and 133.4 53.4, respectively). This correlated with a significant increase (P<0.05) in uterine oxytocin receptor number at day 21 (days 21, 15 and 20 : 540 89, 53 24, 89 35 fmoles/mg protein, respectively). However, the kids at days 15, 20 and 21 did not differ (P>0.05). Finally no difference (P>0.05) in oxytocin receptor number or affinity was detected between incubated and non-incubated tissue. The results of these studies suggest that either pre-oxytocin or post-oxytocin receptor factors are important in determining the uterine myometrial responsiveness to oxytocin.

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Anxiolytic-Like Effects of Chrysanthemum indicum Aqueous Extract in Mice: Possible Involvement of GABAA Receptors and 5-HT1A Receptors

  • Hong, Sa-Ik;Kwon, Seung-Hwan;Kim, Min-Jung;Ma, Shi-Xun;Kwon, Je-Won;Choi, Seung-Min;Choi, Soo-Im;Kim, Sun-Yeou;Lee, Seok-Yong;Jang, Choon-Gon
    • Biomolecules & Therapeutics
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    • v.20 no.4
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    • pp.413-417
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    • 2012
  • Chrysanthemum indicum Linne is an ancient herbal medicine used to treat bone and muscle deterioration, ocular inflammation, headache, and anxiety in Korea, China, and Japan. Furthermore, tea derived from Chrysanthemum indicum Linne has been used to treat anxiety by facilitating relaxation and curing insomnia. However, no reports exist on the anxiolytic-like effects of Chrysanthemum indicum Linne water extract (CWE) in mice. In the present study, we investigated the anxiolytic-like effects of CWE using the elevated plus-maze (EPM) test in mice. CWE, at a dose of 500 mg/kg (p.o.), significantly increased the time spent in the open arms of the EPM compared to a vehicle-injected control group. Moreover, the effect of CWE (500 mg/kg) was blocked by bicuculline (a selective $GABA_A$ receptor antagonist) and WAY 100635 (a selective 5-$HT_{1A}$ receptor antagonist). Taken together, these findings suggest that the anxiolytic-like effects of CWE might be mediated by the $GABA_A$ receptor and the 5-$HT_{1A}$ receptor.

Pharmacological Characterization of KR-31125, a Novel Nonpeptide AT1 Receptor Antagonist (안지오텐신 수용체 길항제 KR-31125의 특성에 관한 연구)

  • Lee, Sung-Hou
    • Journal of Life Science
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    • v.20 no.6
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    • pp.831-837
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    • 2010
  • KR-31125 (2-butyl-5-dimethoxymethyl-6-phenyl-7-methyl-3-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]-3H-imidazo[4,5-b]pyridine) is a potent inhibitor of angiotensin II type 1 ($AT_1$) receptors in human recombinant $AT_1$ receptors and rabbit aorta. These in vitro studies revealed that KR-31125 inhibited specific [$^{125}I$] [$Sar^1$, $Ile^8$]-angiotensin II binding to human recombinant $AT_1$ receptors in a concentration dependent manner with an $IC_{50}$ value of $19.72{\pm}2.65$ nM. However, no interaction with $AT_2$ receptors was detected as displayed by the competition binding of [$^{125}I$] CGP 42112A to human recombinant $AT_2$ receptor. The binding action was also confirmed as a competitive mode that was identical to the previously studied compound, losartan. In addition, KR-31125 caused a nonparallel shift to the right in the concentration response curves to angiotensin II with a 30-80% decrease in the maximum contractile responses ($pK_B$: 7.63). Compared to the previous studies with losartan that showed a parallel right shift in the maximum contractile responses to AII ($pA_2$: 7.59), KR-31125 presented a different mode of action with a similar potency to losartan. These results demonstrate that KR-31125 is a highly potent and $AT_1$ selective angiotensin II receptor antagonist that can be applied to the fields of new diagnostic and research tools with upcoming in vivo study results.

Ginsenoside Rg1 enhances the healing of injured tendon in achilles tendinitis through the activation of IGF1R signaling mediated by oestrogen receptor

  • Wu, Tianyi;Qi, Wenxiao;Shan, Haojie;Tu, Bin;Jiang, Shilin;Lu, Ye;Wang, Feng
    • Journal of Ginseng Research
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    • v.46 no.4
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    • pp.526-535
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    • 2022
  • Background: During the pathogenesis of tendinopathy, the chronic inflammation caused by the injury and apoptosis leads to the generation of scars. Ginsenoside Rg1 (Rg1) is extracted from ginseng and has anti-inflammatory effects. Rg1 is a unique phytoestrogen that can activate the estrogen response element. This research aimed to explore whether Rg1 can function in the process of tendon repair through the estrogen receptor. Methods: In this research, the effects of Rg1 were evaluated in tenocytes and in a rat model of Achilles tendinitis (AT). Protein levels were shown by western blotting. qRT-PCR was employed for evaluating mRNA levels. Cell proliferation was evaluated through EdU assay and cell migration was evaluated by transwell assay and scratch test assay. Results: Rg1 up-regulated the expression of matrix-related factors and function of tendon in AT rat model. Rg1 reduced early inflammatory response and apoptosis in the tendon tissue of AT rat model. Rg1 promoted tenocyte migration and proliferation. The effects of Rg1 on tenocytes were inhibited by ICI182780. Rg1 activates the insulin-like growth factor-I receptor (IGF1R) and MAPK signaling pathway. Conclusion: Rg1 promotes injured tendon healing in AT rat model through IGF1R and MAPK signaling pathway activation.

Role of Spinal Adenosine $A_2$ Receptor in the cardiovascular Regulation in Rats (흰쥐에서 실혈관 조절기전에 대한 척수의 Adenosine $A_2$수용체의 역할)

  • 문삼영;신현진;신인철;고현철;엄애선;박정로;김범수;강주섭
    • Biomolecules & Therapeutics
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    • v.8 no.4
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    • pp.325-331
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    • 2000
  • The present study was designed to assess the role of spinal adenosine $A_2$ receptor in the regulation of cardiovascular functions such as mean arterial pressure (MAP) and heart rate (HR) in male Sprague-Dawley rats. Rats (250~300 g) were anesthetized with urethane and paralyzed with d-tubocurarine and artificially ventilated. blood pressure and HR were continuously monitored via a femoral catheter connected to a pressure transducer and a polygraph. Drugs were administered intrathecally using injection cannula through guide cannula which was inserted inthrathecally at lower thoracic level through a puncture of an atlantooccipital mombrane. Intrathecal injection of an adenosine $A_2$ receptor agonist, 5'-(N-cyclopropyl)-carboxamaidoadenosine (CPCA; 1, 2 and 3 nmol, respectively), produced a dose-dependent decrease in MAP and HR. Pretreatment with $N^{G}$-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor or 10 nmol of MDL-12,330, an adenylate cyclase inhibitor blocked significantly the depressor and bradycardic effect of 2 nmol of CPCA. But, Pretreatment with 3 nmol of bicuculline, gamma-aminobutyric acid A (GAB $A_{A}$) receptor antagonist, or 50 nmol of 5-aminovaleric acid, GAB $A_{B}$ receptor antagonist did not inhibit the depressor and bradycardic effect of 2 nmol of CPCA. These results indicate that adenosine $A_2$ receptor in the spinal cord plays an inhibitory role in the regulation of cardiovascular function and that the depressor and bradycardic action of adonosine $A_2$ receptor are mediated via the synthesis of nitric oxide and the activation of adenylate cyclase in the spinal cord of rats.s.s.s.

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Regulation of Adenosine Receptors in Rat Brain following Chronic Carbamazepine Treatment

  • Park, Kyung-Sun;Yang, Wan-Suk;Kim, Kyung-Hwan
    • The Korean Journal of Physiology and Pharmacology
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    • v.1 no.1
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    • pp.13-17
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    • 1997
  • Carbamazepine (CBZ), an anticonvulsant, has beeen reported to displace ligands at adenosine receptors. Several studies have demonstrated that as far as $A_2$adenosine receptors is concerned, CBZ acts as an antagonist. However, the situation with regard to Al receptors is less straightforward. In this study, we describe the effects of one-week CBZ treatment (25 mg/kg/day) on cerebrocortical $A_1$ adenosine receptors. $A_1$ adenosine receptor bindings as determined by using $[^3CH]DPCPX$ was not significantly altered in membranes prepared from CBZ-treated rats. However, there was a significant decrease in the $A_1$ adenosine receptor-mediated stimulation of $[^{35}S]GTP_{\gamma}S$ binding to cerebrocortical membranes prepared from CBZ-treated rats (20.0% decrease in basal activity; 17.8% decrease in maximal activity). The basal and $10^{-4}$ M forskolin-stimulated adenylyl cyclase activities were relatively unaffected by CBZ treatment, but 10 mM NaF-stimulated adenylyl cyclase activity was significantly reduced in CBZ-treated rats. It appears that one-week CBZ treatment caused an uncoupling of adenosine receptors from G proteins without alteration of $A_1$ adenosine receptor molecules, suggesting that CBZ acts as an agonist at $A_1$ adenosine receptors in rat brain.

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Lower Incidence but More Aggressive Behavior of Right Sided Breast Cancer in Pakistani Women: Does Right Deserve More Respect?

  • Fatima, Nosheen;Zaman, Maseeh Uz;Maqbool, Aamir;Khan, Shaista H.;Riaz, Nazia
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.1
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    • pp.43-45
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    • 2013
  • Background: The aim of this epidemiological study was to establish the laterality of breast cancer (BC) and its association with size, receptor status of the primary tumor and bone metastasis (BM) in a local population. Materials and Methods: This retrospective study included cases of BC from Jan-2009 to Dec-2011 who were referred for metastatic work up or follow up survey with Technetium-99m MDP bone scan (BS) to the Nuclear Medicine Department of Karachi Institute of Radiotherapy and Nuclear Medicine (KIRAN). A total of 384 patients out of 521 were included and all reviewed for age, primary tumor size (PTS), laterality, receptor status like estrogen receptor (ER) progesterone receptor (PR) and Her-2-Neu receptor, presence or absence of BM with sites of involvement and time interval between diagnosis of BC and appearance of BM. Results: The left to right sided BC proportion was significantly higher than unity (59%:41%; p<0.001). The right sided BC was observed in younger age group (46:52 years; p<0.0001) and with a smaller PTS than the left sided (3.43:4.15 cm; p<0.0001). The patients with BM had relatively higher negative receptor status with a significant predominance of right sided BC. The overall incidence of BM on BS was 28% and relatively higher in right than left breast (33%:24% p=0.068). The average number of BM sites was also significantly greater for the right side (6:4, P<0.0001). The % cumulative risk of BM in right breast was noted at significantly smaller PTS than left side with log rank value of 5.579; p<0.05. The Kaplan Meier survival plot for event free survival of BM in left sided BC was significantly higher than for the right side (log rank value=4.155, p<0.05), with an earlier appearance of BM in right BC. Conclusions: 1) A left sided predominance of BC was seen in local population; 2) right sided BC had a more aggressive behavior with extensive and earlier appearance of BM at relatively younger age, smaller PTS and receptor (s) negativity.

Synthesis and Binding Affinity of Homologated Adenosine Analogues as A3 Adenosine Receptor Ligands

  • Lee, Hyuk-Woo;Choi, Won-Jun;Jacobson, Kenneth A.;Jeong, Lak-Shin
    • Bulletin of the Korean Chemical Society
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    • v.32 no.5
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    • pp.1620-1624
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    • 2011
  • Homologated analogues 3a and 3b of potent and selective A3 adenosine receptor ligands, IB-MECA and dimethyl-IB-MECA were synthesized from commercially available 1-O-acetyl-2,3,5-tri-O-benzoyl-${\beta}$-D-ribofuranose (4) via $Co_2(CO)_8$-catalyzed siloxymethylation as a key step. Unfortunately, homologated analogues 3a and 3b did not show significant binding affinities at three subtypes of adenosine receptors, indicating that free rotation, resulting from homologation, induced unfavorable interactions in the binding site of the receptor maybe due to the presence of many conformations.