• 통합자연과학논문집
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• 제5권3호
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• pp.168-174
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• 2012

Gal (1-3) receptors are members of GPCR superfamily with seven transmembrane helices. The neuropeptide galanin mediates its effects through the receptor subtypes Gal1, Gal2, and Gal3 and has been implicated in anxiety and depression related behaviors. Galanin receptors are considered to be important targets for the development of novel antidepressant drugs. Owing to the importance of these receptors, a short communication about the sequential and structural studies about the functional Galanin (1-3) receptors has been reported. Structural studies have been hampered due to the lack of X-ray crystal structures. However with the availability of templates with close homologs comparative modeling could be encouraging. Sequence analysis was done for each receptors and homology modeling of each receptors were done with recently reported templates. Comparative analyses were done between these receptors to identify the relationships between them sequentially. Phylogram was generated between these receptors to identify the close homologue between this receptor and found that Gal2 and Gal3 receptors are closer. Our results could be useful for further structure based drug design targeting Gal1, Gal2 and Gal3 receptors.

• 대한약리학회지
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• 제32권3호
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• pp.311-321
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• 1996

$M_1$과 $M_2$ 무스카린성 수용체의 두 번째 transmembrane domain의 C-말단에는 leucine(L), tyrosine(Y), threonine(T)로 구성된 3중체(triplet)가 있다. 이 3중체는 $M_2$ 무스카린성 수용체에서는 두 번째 transmembrane domain과 첫 번째 세포외 고리사이의 연접부위에서 LYT-LYT의 반복구조로 존재하며 $M_1$ 무스카린성 수용체에서는 흥미롭게도 LYT-TYL의 역상구조로 존재한다. 본 연구에서는 site-directed mutagenesis방법을 사용하여 이와 같은 특이한 구조적차이가 두 subtype의 수용체의 기능상 차이와 관련한 역할을 가지고 있는지를 확인하고자 하였다. $M_1$ 수용체에서는 LYTTYL서열을 $M_2$ 수용체의 서열에 해당하는 LYTLYT로 mutation시켰으며 $M_2$ 수용체에서는 LYTLYT8서열을 $M_1$ 수용체의 서열에 해당하는 LYTTYL로 mutation시켰다. 이와같은 mutation은 $M_1$과 $M_2$ 수용체에서 효능제 carbachol의 수용체 결합친화력에 유의한 변화를 주지 않았다. 또한 $M_1$ 수용체에서의 mutation은 cyclic AMP 증가작용에 대한 coupling은 변화시키지 않고 phosphoinositides (PI) hydrolysis 촉진작용과 세포내 $Ca^{2+}$ 농도 상승을 현저히 증가시켰다. 또한 $M_2$ 수용체에서의 mutation은 adenylate cyclase 억제에 대한 coupling은 변화시키지 않고 PI hydrolysis 촉진을 약간 증가 시켰다. 이상의 결과는 $M_1$과 $M_2$ 수용체에서 LYTTYL/LYTLYT 아미노산 서열의 차이는 두 수용체의 PI hydrolysis에 대한 coupling을 조절하는 역할을 하지만, 두 수용체 사이에서 ligand 결합과 신호전달계의 차이를 구분하는데 중요한 역할을 하지는 않는다.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 2002년도 학술대회지
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• pp.96-112
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• 2002

In the present study, we have investigated the effects of centrally administered ginsenoside Rc or Rgl on the modulation of NMDA receptor and $GABA_A$ receptor binding in rat brain. The NMDA receptor binding was analyzed by quantitative autoradiography using $[^3H]MK-801$ binding, and $GABA_A$ receptor bindings were analyzed by using $[^3H]muscimol\;and\;[^3H]flunitrazepam$ in rat brain slices. Rats were infused with ginsenoside Rc or Rg1 ($10\;{\mu}g/10{\mu}l/hr$, i.c.v.) for 7 days, through pre-implanted cannula by osmotic minipumps (Alzet, model 2ML), The levels of $[^3H]MK-801$ binding were highly decreased in part of cortex and cingulated by ginsenoside Rc and Rgl. The levels of $[^3H]muscimol$ binding were strongly elevated in almost all regions of frontal cortex by the treatment of ginseoside Rc but decreased by ginsenoside Rg 1. However, the $[^3H]flunitrazepam$ binding was not modulated by ginsenoside Rc or ginsenoside Rgl infusion. These results suggest that prolonged infusion of ginsenoside could differentially modulate $[^3H]MK-801\;and\;[^3H]muscimol$ binding in a region-specific manner. Also, we investigated the influence of centrally administered ginsenoside on the regulation of mRNA levels of the family of NMDA receptor subtypes (NR1, NR2A, NR2B, NR2C) by in situ hybridization histochemistry in the rat brain. The level of NR1 mRNA is significantly increased in temporal cortex, caudate putamen, hippocampus, and granule layer of cerebellum in Rgl-infused rats as compared to control group. The level of NR2A mRNA is elevated in the frontal cortex. In contrast, it was decreased in CAI area of hippocampus in Rgl-infused rats. However, there was no significant change of NR1 and NR2A mRNA levels in Rc-infused rats. The level of NR2B mRNA is elevated in cortex, caudate putamen, and thalamus in both Rc- and Rg-infused rats. In contrast, NR2B level is decreased in CA3 in Rgl-infused rats. The level of NR2C mRNA is increased in the granule layer of cerebellum in only Rg1 but not Rc infused rats. These results show that structure difference of ginsenoside may diversely affect the modulation of expression of NMDA receptor subunit mRNA after infusion into cerebroventricle in rats.

• International Journal of Oral Biology
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• 제34권4호
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• pp.215-222
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• 2009

Medial vestibular nucleus (MVN) neurons are involved in the reflex control of the head and eyes, and in the recovery of vestibular function after the formation of peripheral vestibular lesions. In our present study, whole cell patch clamp recordings were carried out on MVN neurons in brainstem slices from neonatal rats to investigate the actions of a group I metabotropic glutamate receptor (mGluR) agonist upon synaptic transmission and ionic currents. Application of the mGluR I agonist (S)-3,5- dihydroxyphenylglycine (DHPG) increased the frequency of miniature inhibitory postsynaptic currents (mIPSCs) but had no effect upon amplitude distributions. To then identify which of mGluR subtypes is responsible for the actions of DHPG in the MVN, we employed two novel subtype selective antagonists. (S)-(+)-$\alpha$-amino-a-methylbenzeneacetic acid (LY367385) is a potent competitive antagonist that is selective for mGluR1, whereas 2-methyl-6-(phenylethynyl)-pyridine (MPEP) is a potent noncompetitive antagonist of mGluR5. Both LY367385 and MPEP antagonized the DHPG-induced increase of mIPSCs, with the former being more potent. DHPG was also found to induce an inward current, which can be enhanced under depolarized conditions. This DHPG-induced current was reduced by both LY367385 and MPEP. The DHPG-induced inward current was also suppressed by the PLC blocker U-73122, the $IP_3$ receptor antagonist 2-APB, and following the depletion of the intracellular $Ca^{2+}$ pool by thapsigargin. These data suggest that the DHPG-induced inward current may be mainly regulated by the intracellular $Ca^{2+}$ store via the PLC-$IP_3$ pathway. In conclusion, mGluR I, via pre- and postsynaptic actions, may modulate the excitability of the MVN neurons.

• Asian Pacific Journal of Cancer Prevention
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• 제15권19호
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• pp.8441-8445
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• 2014

Background: Paired-like homeodomain transcription factor 2 (PITX2) is another new marker in breast carcinoma since hypermethylation at P2 promoter of this gene was noted to be associated with poor prognosis. We investigated the expression of PITX2 protein using immunohistochemistry in invasive ductal carcinoma and its association with the established growth receptors such as estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth receptor 2 (HER2). Methods: We conducted a cross sectional study using 100 samples of archived formalin-fixed paraffin embedded tissue blocks of invasive ductal carcinoma and stained them with immunohistochemistry for PITX2, ER, PR and HER2. All HER2 with scoring of 2+ were confirmed with chromogenic in-situ hybridization (CISH). Results: PITX2 protein was expressed in 53% of invasive ductal carcinoma and lack of PITX2 expression in 47%. Univariate analysis revealed a significant association between PITX2 expression with PR (p=0.001), ER (p=0.006), gland formation (p=0.044) and marginal association with molecular subtypes of breast carcinoma (p=0.051). Combined ER and PR expression with PITX2 was also significantly associated (p=0.003) especially in double positive cases. Multivariate analysis showed the most significant association between PITX2 and PR (RR 4.105, 95% CI 1.765-9.547, p=0.001). Conclusion: PITX2 is another potential prognostic marker in breast carcinoma adding significant information to established prognostic factors of ER and PR. The expression of PITX2 together with PR may carry a very good prognosis.

• Asian Pacific Journal of Cancer Prevention
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• 제16권5호
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• pp.1707-1713
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• 2015

Eighty six cases of invasive ductal breast carcinomas were utilized to investigate GSTP1 polymorphisms in certain immunohistochemistry (IHC) subtypes of breast cancer with respect to ER, PR and HER2 expression. The frequency of wild allele homozygote, heterozygote and variant allele homozygote genotypes were 46.5%, 52.3% and 1.16% respectively; Whereas 54.3% of the control subjects were GSTP1 wild type allele homozygous, 40.0% were heterozygous and 5.71% mutant allele homozygous. There was dramatic inverted relation between positive IHC ER staining and increasing grade of tumors in general (100%, 88.6%, 40.4%) and especially among tumors with heterozygote genotype of GSTP1 (70%, 35.4%, 22.7). There was increase in positive IHC HER2 staining consistent with higher grades in general (20%, 29.6%, 50.0%), especially among tumors with GSTP1 wild allele homozygote genotype (5.0%, 9.1%, 31.8%). A remarkable reverse relation was also observed between the fraction of IHC hormone receptor phenotype ER+/PR+/ HER2- and increased grade of tumors (60.0%, 45.5%, and 27.3%) especially among tumors with GSTP1 heterozygote genotype, and a similar link was noted regarding ER+/PR-/ HER2- and tumor grade. There was increase in frequency of ER-/PR-/ HER2- (0.0%, 6.8%, and 18.2%) and ER-/PR-/ HER2+ (0.0%, 4.54%, and 40.9%) consistent with the higher grades of tumors in general and especially GSTP1 heterozygote genotype tumors. As a conclusion, there is no correlation between GSTP1 polymorphism and increased risk of breast cancer i.e. the mutant allele is randomly distributed in cancer and control cases. However, there is a link between GSTP1 genotypes and hormone receptor expression status and certain phenotypes of breast cancer, which may have clinical importance.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1996년도 춘계학술대회
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• pp.252-252
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• 1996

We Investigated the peripheral excitatory effect of capsaicin and KR-25018, a newly synthesized capsaicin derivative which was demonstrated to have a potent analgesic activity. KR-25018 and capsaicin were found to be both potent efficacious contractors of isolated guinea pig bronchial smooth muscle. KR-25018 was equipotent with capsaicin and [Sar$\^$9/,Met(O$_2$)$\^$11/]-substance P, 10-fold more potent than histamine and 10-fold less potent than (${\beta}$ -Ala$\^$8/)-neurokinin A(4-10), and their -log(M)EC$\_$50/ values were 6.94${\pm}$0.08, 6.86${\pm}$0.05, 6.96${\pm}$0.07, 5.64${\pm}$0.04, 7.96${\pm}$0.02, respectively. Contractile responses to KR-25018 and capsaicin were potentiated by phosphoramidon (1 ${\mu}$M), an inhibitor of neuropeptide-inactivating endopeptidase, but completely abolished in a calcium-free medium. These responses to KR-25018 and capsaicin were unaffected by the NK-1 antagonist CP96345 (1${\mu}$M), partially inhibited by the NK-2 antagonist SR48968 (1 ${\mu}$M) but almost completely abolished by a combination of the antagonists. A vanilloid receptor antagonist capsazepine competitively antagonized the responses to both KR-25018 and capsaicin (pA$_2$: aganst KR-25018, 5.98${\pm}$0.47; against capsaicin, 5.80${\pm}$0.31), and a capsaicin-sensitive cation channel antagonist ruthenium red caused significant reduction in the maximum responses to KR-25018 and capsaicin (pD'$_2$: against KR-25018, 4.61${\pm}$0.33; against capsaicin 4.96${\pm}$0.21). In conclusion, the present results suggest that KR-25018 and cpasaicin act on the same vanilloid receptor inducing the influx of calcium through ruthenium red-sensitive cation channel and produce contractile responses via the release of tachykinins that act on both NK-1 and NK-2 receptor subtypes.

• Biomolecules & Therapeutics
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• 제30권4호
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• pp.320-327
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• 2022

Neurodevelopmental disorders are complex conditions that pose difficulty in the modulation of proper motor, sensory and cognitive function due to dysregulated neuronal development. Previous studies have reported that an imbalance in the excitation/inhibition (E/I) in the brain regulated by glutamatergic and/or GABAergic neurotransmission can cause neurodevelopmental and neuropsychiatric behavioral deficits such as autism spectrum disorder (ASD). NMDA acts as an agonist at the NMDA receptor and imitates the action of the glutamate on that receptor. NMDA however, unlike glutamate, only binds to and regulates the NMDA receptor subtypes and not the other glutamate receptors. This study seeks to determine whether NMDA administration in mice i.e., over-activation of the NMDA system would result in long-lasting behavioral deficits in the adolescent mice. Both gender mice were treated with NMDA or saline at early postnatal developmental period with significant synaptogenesis and synaptic maturation. On postnatal day 28, various behavioral experiments were conducted to assess and identify behavioral characteristics. NMDA-treated mice show social deficits, and repetitive behavior in both gender mice at adolescent periods. However, only the male mice but not female mice showed increased locomotor activity. This study implies that neonatal exposure to NMDA may illicit behavioral features similar to ASD. This study also confirms the validity of the E/I imbalance theory of ASD and that NMDA injection can be used as a pharmacologic model for ASD. Future studies may explore the mechanism behind the gender difference in locomotor activity as well as the human relevance and therapeutic significance of the present findings.

• Biomolecules & Therapeutics
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• 제31권3호
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• pp.312-318
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• 2023

The natural flavonoid macakurzin C (1) exhibited adiponectin biosynthesis-inducing activity during adipogenesis in human bone marrow mesenchymal stem cells and its molecular mechanism was directly associated with a pan-peroxisome proliferator-activated receptor (PPAR) modulator affecting all three PPAR subtypes α, γ, and δ. In this study, increases in adiponectin biosynthesis-inducing activity by macakurzin C derivatives (2-7) were studied. The most potent adiponectin biosynthesis-inducing compound 6, macakurzin C 3,5-dimethylether, was elucidated as a dual PPARα/γ modulator. Compound 6 may exhibit the most potent activity because of the antagonistic relationship between PPARδ and PPARγ. Docking studies revealed that the O-methylation of macakurzin C to generate compound 6 significantly disrupted PPARδ binding. Compound 6 has therapeutic potential in hypoadiponectinemia-related metabolic diseases.

• Biomolecules & Therapeutics
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• 제31권2호
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• pp.176-182
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• 2023

Among 14 subtypes of serotonin receptors (5-HTRs), 5-HT_2AR plays important roles in drug addiction and various psychiatric disorders. Agonists for 5-HT_2AR have been classified into three structural groups: phenethylamines, tryptamines, and ergolines. In this study, the structure-activity relationship (SAR) of phenethylamine and tryptamine derivatives for binding 5-HT_2AR was determined. In addition, functional and regulatory evaluation of selected compounds was conducted for extracellular signal-regulated kinases (ERKs) and receptor endocytosis. SAR studies showed that phenethylamines possessed higher affinity to 5-HT_2AR than tryptamines. In phenethylamines, two phenyl groups were attached to the carbon and nitrogen (R³ ) atoms of ethylamine, the backbone of phenethylamines. Alkyl or halogen groups on the phenyl ring attached to the β carbon exerted positive effects on the binding affinity when they were at para positions. Oxygen-containing groups attached to R³ exerted mixed influences depending on the position of their attachment. In tryptamine derivatives, tryptamine group was attached to the β carbon of ethylamine, and ally groups were attached to the nitrogen atom. Oxygen-containing substituents on large ring and alkyl substituents on the small ring of tryptamine groups exerted positive and negative influence on the affinity for 5-HT_2AR, respectively. Ally groups attached to the nitrogen atom of ethylamine exerted negative influences. Functional and regulatory activities of the tested compounds correlated with their affinity for 5-HT_2AR, suggesting their agonistic nature. In conclusion, this study provides information for designing novel ligands for 5-HT_2AR, which can be used to control psychiatric disorders and drug abuse.