• The Korean Journal of Pharmacology
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• v.30 no.2
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• pp.153-165
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• 1994

In this study, we tested the influences of several ${\kappa}$ opioid ligands on the $[^3H]diprenorphine$ binding in rat and guinea pig cortex membrane preparations. Using paradigm to block ${\mu}\;and\;{\delta}$ opioid receptors with $DAMGO(1{\mu}M)$ and $DPDPE(1{\mu}M)$, $[^3H]diprenorphine$ labeled ${\kappa}$ sites. Competition analysis in both rat and guinea pig cortex has shown a single population of $[^3H]diprenorphine$ binding site with different Kd values, respectively. There is a significant difference in Ki values of (-) WIN44441 and (+)WIN44441 in both rat and guinea pig cortex. Bremazocine, (-)ethylketocyclazocine, (-)cyclazocine, nor-binaltorphimine effectively inhibited the $[^3H]diprenorphine$ binding with different Ki values in rat and guinea pig cortex. U-69,593, U-50,488H and dynorphine-A (1-8) did not inhibit the $[^3H]diprenorphine$ binding in rat but in guinea pig cortex. Nor-binaltorphimine was a ligand discriminate the ${\kappa}_1$, and ${\kappa}_2$ receptor most effectively. We, also, examined the influence of Na ion and $GTP{\gamma}S$, a nonhydrolyzable guanine nucleotide analog, on the inhibition of $[^3H]diprenorphine$ binding by diprenorphine, (-)ethyl-ketocyclazocine, U-69,593 and bremazocine. By the replacement of NaCl with N-methy-D-glucamine or addition of $GTP{\gamma}S$, Ki values of diprenorpnine were not changed and that of ethylketocyclazocine were changed significantly in both rat and guinea pig cortex. The Ki value of bremazocine was decreased by removal of Na ion, and increased by $GTP{\gamma}S$, however, was not changed by any one of either. These results suggest that there are 2 kinds of subtypes of ${\kappa}$ opioid receptor, ${\kappa}_1$, and ${\kappa}_2$, showing different Ki values for various ${\kappa}$ opioid ligands, also, bremazocine possess the antagonistic property at ${\kappa}_2$ site which is dominant subtype of K receptor in rat cortex.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.1
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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.

• Development and Reproduction
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• v.6 no.2
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• pp.111-115
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• 2002

5-Hydroxytryptamine(5-HT; serotonin) system has been implicated in the modulation of male sexual behaviors and the secretion of reproductive hormones. In human males, selective serotonin re-uptake inhibitors(SSRIs) are known to improve the major male sexual dysfunction, premature ejaculation, through the central nervous system-mediated pathways. As numerous hormone and local factors, 5-HT may have peripheral role in the regulation of male sexual function. The expression of 5-HT receptor subtypes in the target tissue, however, has not been explored yet. The present study was undertaken to test whether the 5-HT receptor subtypes are expressed in the reproductive tissues of male rat, especially in ejaculatory machinery such as seminal vesicle and vas deferens. To do this, reverse transcription-polymerase chain reaction(RT-PCR) and Southern blot analysis were employed. The transcripts for the 1A, 1B and 2C subtypes of 5-HT receptor were amplified in all the tested tissues. The present study demonstrated the expression of 5-HT receptor in the rat ejaculatory machinery, suggesting that 5-HT may play a pivotal role in the male sexual function via not only central pathway but also peripheral route. Further study on the receptor subtype-specific effect and their harmonized mode of action will be needed to establish the understanding of ejaculation mechanism and drug design.

• Anxiety and mood
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• v.2 no.2
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• pp.79-85
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• 2006

Anxiety and anxiety disorders are related to many neurotransmitters, such as norepinephrine, serotonine, dopamine, glutamate, and Gamma-aminobutyric acid (GABA). GABA, the main inhibitory neurotransmitter of the CNS, is known to counterbalance the action of the excitatory neurotransmitters and control anxiety. GABA acts on 3 GABA receptor subtypes, $GABA_A$, $GABA_B$, and $GABA_C$. $GABA_A$ and $GABA_c$ receptors are oligomeric transmembrane glycoproteins composed of 5 subunits that are arranged around a central chloride channel. $GABA_B$ receptor comprises two 7-transmembraneis-spanning proteins that are coupled to either calcium or potassium channel via G proteins. This article highlights neurobiological interactions between anxiety and GABA system.

• Journal of Integrative Natural Science
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• v.5 no.2
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• pp.65-71
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• 2012

Neuropeptide Y (NPY), a 36-amino acid polypeptide, is a member of the pancreatic polypeptide family, which consists of NPY, peptide YY (PYY) and pancreatic polypeptide (PP). The neuropeptide Y (NPY) receptors called Y receptors belongs to G-protein coupled that are involved in a variety of physiological functions such as appetite regulation, circadian rhythm and anxiety. Five receptor subtypes have been cloned in mammals (Y1, Y2, Y4, Y5, and Y6) of which four are functional. In this short review, information about the functional NYP receptors was analyzed. Sequence analyses were done between these receptors to identify the relationships between them. Phylogram was generated between these receptors to identify the close homologue between these receptors. Our sequence analyses found that Y1 and Y4 receptors are close than the other receptors. Further structure based analysis could be useful to identify subtype selective antagonists and dual antagonists targeting Y1 and Y4 receptors.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.10
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• pp.5081-5086
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• 2012

Background: The liver is one of the most common metastatic sites of breast cancer, hepatic metastases developing in 6%-25% of patients with breast cancer and being associated with a poor prognosis. The aim of this study was to analyze the survival and clinical characteristics of patients with hepatic metastases from breast cancer of different molecular subtypes and to investigate the prognostic and predictive factors that effect clinical outcome. Methods: We retrospectively studied the charts of 104 patients with breast cancer hepatic metastases diagnosed at Sun Yat-sen University Cancer Center from December 1990 to June 2009. Subtypes were defined as luminal A, luminal B, human epidermal growth factor receptor 2 (HER2) enriched, triple-negative (TN). Prognostic factor correlations with clinical features and treatment approaches were assessed at the diagnosis of hepatic metastases. Results: The median survival time was 16.0 months, and the one-, two- three-, four-, five-year survival rates were 63.5%, 31.7%, 15.6%, 10.8%, and 5.4%, respectively. Median survival periods after hepatic metastases were 19.3 months (luminal A), 13.3 months (luminal B), 18.9 months (HER2-enriched), and 16.1 months (TN, P=0.11). In multivariate analysis, a 2 year-interval from initial diagnosis to hepatic metastasis, treatment with endocrine therapy, and surgery were independent prognostic factors. Endocrine therapy could improve the survival of luminal subtypes (P=0.004) and was a favorable prognostic factor (median survival 23.4 months vs. 13.8 months, respectively, P=0.011). Luminal A group of patients treated with endocrine therapy did significantly better than the Luminal A group of patients treated without endocrine therapy (median survival of 48.9 vs. 13.8 months, P=0.003). Conclusions: Breast cancer subtypes were not associated with survival after hepatic metastases. Endocrine therapy was a significantly favorable treatment for patients with luminal subtype.

• Animal cells and systems
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• v.6 no.3
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• pp.253-261
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• 2002

Although cardiac distribution of specific receptors for atrial natriuretic peptide (ANP) was mainly observed in the ventricular endocardium, the modulation of ANP receptors in relation to cardiac development is not defined. The present study was undertaken to investigate ANP receptor modulation in rat during development. In the developmental stages examined (fetus, after postnatal 3-days, 1-, 2-, 3-, 4-, and 8-week-old Sprague Dawley rats) specific ANP binding sites were localized in the right and left ventricular endo-cardia by quantitative in vitro receptor autoradiography using (equation omitted)-rat ANP as labeled ligand. The specific bindings to endocardium were much higher in the right than the left ventricle. The binding affinities of ANP were much higher in the right than the left ventricular endocardium. The difference of these binding affinities among various developmental stages was not observed in the right ventricle, whereas the binding affinity in left ventricle was gradually increased with aging and reached the peak value at 8 weeks. No significant difference in maximal binding capacities of endocardial bindings was observed in the right and left ventricular endocardia during developmental stages. Also, cGMP production via activation of particulate guanylyl cyclase-coupled receptor subtypes in the ventricular membranes was gradually decreased with close relationship to aging. Therefore, the present study show that the endocardial ANP receptor is modulated with close relationship to cardiac development in the left ventricle rather than the right ventricle, and may be involved in regulating myocardial contractility in left heart.

• Biomedical Science Letters
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• v.14 no.2
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• pp.69-76
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• 2008

${\gamma}$-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the central nervous system, and its actions are mediated by subtypes of GABA receptors named as $GABA_A$, $GABA_B,\;and\;GABA_C,\;GABA_A$, receptor consisting of ${\alpha},\;{\beta},\;{\gamma}\;and\;{\delta}$ subunits is a heterooligomeric ligand-gated chloride channel. This study was performed to investigate regulation of $GABA_A$ receptor by protein kinase C(PKC). Ion currents were recorded using gramicidine-perforated patch and whole cell patch clamp. mRNA encoding the subunits of PKC expressed in major pelvic ganglion (MPG) neurons was detected by using RT-PCR. The GABA-induced inward current was increased by PKC activators and decreased by PKC inhibitors, respectively. These effects were not associated with intracellular $Ca^{2+}$ and GAG (1-oleoyl-2-acetyl-sn-glycerol), a membrane permeable diacylglycerol (DAG) analogue. These results mean that the subfamily of PKC participating in activation of $GABA_A$ receptor would be an atypical PKC (aPKC). Among theses, ${\xi}$ isoform of aPKC was detected by RT-PCR. Taking together, we suggest that excitable $GABA_A$ receptor in sympathetic MPG neuron seemed to be regulated by aPKC, particular in ${\xi}$ isoform. The regulatory roles of PKC on excitatory $GABA_A$ receptors in sympathetic neurons of MPG may be an important factor to control the functional activity of various pelvic organs such as bowel movement, micturition and erection.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.1
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• pp.55-63
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• 1997

The present study was designed to quantify the alterations of renal renin, angiotensin type I receptor ($AT_1$), $TGF-{\beta}1$, and fibronectin gene expression in rats with unilateral ureteral obstruction (UUO). We also investigated the change of $AT_1$ density during UUO. Reverse transcription-polymerase chain reaction (RT-PCR) technique and receptor binding assay were used to detect mRNA expression and receptor density, respectively. At one day after UUO, renin mRNA level of the obstructed kidneys was decreased transiently and then subsequently increased to the level of sham kidneys. In the contralateral kidneys of the same rats, on the contrary, renin mRNA level was gradually decreased. Then, at 9 days after UUO, it was significantly lower than that of sham kidneys. The expressions of both $AT_1$ subtypes, called $AT_{1A}$ and $AT_{1B}$, mRNAs did not change at any time. UUO led to a significant decrease in $AT_1$ density in the obstructed kidneys compared with the sham kidneys at 1 and 3 days $(66\;{\pm}\;11.6%\;(p<0.005)\;and\;73\;{\pm}\;4.0%$ (p<0.01), respectively). Thereafter, $AT_1$ density was gradually increased and at 9 days it showed a marked elevation in the obstructed kidneys compared to the sham kidneys. In contrast, in the contralateral kidneys $AT_1$ density was significantly reduced from 3 to 9 days after UUO. The $TGF-{\beta}$1 mRNA level of the obstructed kidneys was unexpectedly decreased at 6 days after UUO. Then, at 9 days it was followed by a significant increase in the obstructed kidneys, whereas it showed an obvious decrease in the contralateral kidneys. In addition, fibronectin mRNA level was also significantly increased in the obstructed kidneys after UUO compared to the sham or the contralateral kidneys of the same rats. These results suggest a differential regulation of renal renin, $AT_1$ receptor, $TGF-{\beta}$1 and fibronectin mRNA levels at different stages of UUO.

• YAKHAK HOEJI
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• v.59 no.5
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• pp.207-214
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• 2015

P2Y receptors, a type of P2 receptor family, are G-protein coupled receptors and 8 subtypes have been characterized ($P2Y_1$, $P2Y_2$, $P2Y_4$, $P2Y_6$, $P2Y_{11-14}$). Recently, several studies have shed light on the role of P2Y receptors in bone biology. Among them, little is known on the role of $P2Y_6$ receptor on osteoclast differentiation. Thus, we investigated the role of $P2Y_6$ receptor on osteoclastogenesis using $P2Y_6$ receptor selective antagonist, MRS 2578. When osteoblasts and bone marrow cells were co-cultured in the presence of $VitD_3$ and $PGE_2$, $P2Y_6$ antagonist increased the formation of TRAP positive osteoclasts. To elucidate the target cells of $P2Y_6$ antagonist, we first checked the effect of MRS 2578 on osteoblasts. Treatment of MRS 2578 did not affect OPG : RANKL mRNA ratio in osteoblasts. Next, we checked the effects of $P2Y_6$ antagonist on osteoclast precursors using mouse bone marrow macrophages (BMMs). Addition of MRS 2578 increased the number of osteoclasts in RANKL-treated BMMs. Although $P2Y_6$ antagonist had no effect on RANKL-induced NFATc1, c-Fos and MafB expression levels, it significantly stimulated RANKL-induced Blimp1 mRNA expression in BMMs. Taken together, these data indicate that $P2Y_6$ antagonist increases osteoclast formation by upregulation of Blimp1 expression.