Selective Ligand Conversion of Ethylenediamine Tetraacetate to Its Triacetate on Peroxotitanate(IV)

2007 ◽  
Vol 46 (17) ◽  
pp. 6846-6848 ◽  
Author(s):  
Zhao-Hui Zhou ◽  
Yuan-Fu Deng ◽  
Qiong-Xin Liu ◽  
Hua-Lin Zhang ◽  
Thomas C. W. Mak ◽  
...  
Keyword(s):  
Selective Ligand ◽  
Ethylenediamine Tetraacetate

Characterization of opioid receptors on smooth muscle cells from guinea pig stomach

1992 ◽  
Vol 262 (3) ◽  
pp. G461-G469 ◽  
Author(s):  
L. Zhang ◽  
Z. F. Gu ◽  
T. Pradhan ◽  
R. T. Jensen ◽  
P. N. Maton
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Opioid Receptors ◽  
Muscle Cells ◽  
Receptor Subtypes ◽  
Selective Antagonist ◽  
Kappa Agonist ◽  
Gastric Smooth Muscle ◽  
Selective Ligand ◽  
Guinea Pig Stomach

On the basis of opioid-stimulated contraction of dispersed gastric smooth muscle cells it has been suggested that these cells possess opioid receptors of three subtypes: kappa (kappa), mu (mu), and delta (delta). We have used selective peptidase-resistant radioligands, agonists and antagonists, to examine receptor subtypes on dispersed gastric smooth muscle cells from guinea pigs prepared by collagenase digestion. The kappa-agonist U-50488H, the mu-agonist [D-Ala2,N-Me-Phe4,Gly5-ol]enkephalin (DAGO), and the delta-agonist [D-Pen2,Pen5]enkephalin (DPDPE) each caused muscle contraction. The concentrations required to caused half-maximal contraction were U50488H (6 pM) greater than DAGO (13 pM) greater than DPDPE (6 nM). The abilities of these agonists to inhibit binding of [3H]U-69593 (kappa-preferring) by 50% were U50488H (43 nM) greater than DAGO (43 microM) greater than DPDPE (200 microM). Their abilities to inhibit binding of [3H]naloxone (mu-preferring) by 50% were DAGO (0.2 microM) greater than U50488H (10 microM) greater than DPDPE (greater than 100 microM). No binding could be detected with the delta-selective ligand [3H]DPDPE. The kappa-preferring antagonist Mr2266 (10 nM) preferentially inhibited contraction stimulated by the kappa-agonist U50488H, and naltrexone (10 nM) (mu-selective antagonist) preferentially inhibited contraction stimulated by the mu-agonist DAGO. ICI 174864 (200 microM; delta-selective antagonist) had no effect on contraction stimulated by mu-, kappa-, or delta-agonists. Contraction stimulated by the delta-agonist DPDPE was inhibited by both kappa- and mu-receptor antagonists. Studies on the effect of the antagonists on binding of [3H]naloxone and [3H]U69593 also provided evidence for kappa- and mu-sites but nor for delta-sites.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Interaction between Galectin-3 and Integrins Mediates Cell-Matrix Adhesion in Endothelial Cells and Mesenchymal Stem Cells

2021 ◽  
Vol 22 (10) ◽  
pp. 5144
Author(s):  
Antonín Sedlář ◽  
Martina Trávníčková ◽  
Pavla Bojarová ◽  
Miluše Vlachová ◽  
Kristýna Slámová ◽  
...  
Keyword(s):  
Stem Cells ◽  
Endothelial Cells ◽  
Cell Adhesion ◽  
Vascular Tissue ◽  
Cell Functions ◽  
Matrix Adhesion ◽  
Cell Matrix ◽  
Selective Ligand ◽  
Galectin 3 ◽  
Cell Matrix Adhesion

Galectin-3 (Gal-3) is a β-galactoside-binding protein that influences various cell functions, including cell adhesion. We focused on the role of Gal-3 as an extracellular ligand mediating cell-matrix adhesion. We used human adipose tissue-derived stem cells and human umbilical vein endothelial cells that are promising for vascular tissue engineering. We found that these cells naturally contained Gal-3 on their surface and inside the cells. Moreover, they were able to associate with exogenous Gal-3 added to the culture medium. This association was reduced with a β-galactoside LacdiNAc (GalNAcβ1,4GlcNAc), a selective ligand of Gal-3, which binds to the carbohydrate recognition domain (CRD) in the Gal-3 molecule. This ligand was also able to detach Gal-3 newly associated with cells but not Gal-3 naturally present on cells. In addition, Gal-3 preadsorbed on plastic surfaces acted as an adhesion ligand for both cell types, and the cell adhesion was resistant to blocking with LacdiNAc. This result suggests that the adhesion was mediated by a binding site different from the CRD. The blocking of integrin adhesion receptors on cells with specific antibodies revealed that the cell adhesion to the preadsorbed Gal-3 was mediated, at least partially, by β1 and αV integrins—namely α5β1, αVβ3, and αVβ1 integrins.

The in vitro effect of kynurenic acid on the rainbow trout (Oncorhynchus mykiss) leukocyte and splenocyte activity

2014 ◽  
Vol 17 (3) ◽  
pp. 453-458 ◽  
Author(s):  
J. Małaczewska ◽  
A. K. Siwicki ◽  
R. Wójcik ◽  
W. a. Turski ◽  
E. Kaczorek
Keyword(s):  
Rainbow Trout ◽  
Immune Cells ◽  
Kynurenic Acid ◽  
Kynurenine Pathway ◽  
Phagocytic Cells ◽  
Mitogenic Response ◽  
Tryptophan Degradation ◽  
Selective Ligand ◽  
Vitro Effect

Abstract Kynurenic acid (KYNA), an endogenous neuroprotectant formed along the kynurenine pathway of tryptophan degradation, is a selective ligand of the GPR35 receptor, which can be found on the surface of various populations of human immune cells. In infections and inflammations, KYNA produces an anti-inflammatory effect through this receptor, by depressing the synthesis of reactive oxygen species and pro-inflammatory cytokines. However, it is still unrecognized whether receptors for kynurenic acid are also localized on immune cells of poikilothermic animals, or whether KYNA is able to affect these cells. The objective of this study has been to determine the effect of different concentrations of kynurenic acid (12.5 μM to 10 mM) on the viability and mitogenic response of lymphocytes and on the activity of phagocytic cells isolated from blood and the spleen of rainbow trout. The results imply low toxicity of kynurenic acid towards fish immune cells, and the proliferative effect observed at the two lowest concentrations of KYNA (12.5 μM and 25 μM) seems indicative of endogenous kynurenic acid being capable of activating fish lymphocytes. Non-toxic, micromole concentrations of KYNA, however, had no influence on the mitogenic response of lymphocytes nor on the activity of phagocytes in rainbow trout under in vitro conditions. There is some likelihood that such an effect could be observed at lower, nanomole concentrations of KYNA.

scholarly journals Three amino acids in the D2dopamine receptor regulate selective ligand function and affinity

2009 ◽  
Vol 110 (1) ◽  
pp. 45-57 ◽  
Author(s):  
David F. Cummings ◽  
Spencer S. Ericksen ◽  
John A. Schetz
Keyword(s):  
Amino Acids ◽  
Selective Ligand

3β-(4-Ethyl-3-iodophenyl)nortropane-2β- carboxylic Acid Methyl Ester as a High-Affinity Selective Ligand for the Serotonin Transporter

1997 ◽  
Vol 40 (24) ◽  
pp. 3861-3864 ◽  
Author(s):  
Bruce E. Blough ◽  
Philip Abraham ◽  
Andrew C. Mills ◽  
Anita H. Lewin ◽  
John W. Boja ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Methyl Ester ◽  
Serotonin Transporter ◽  
Acid Methyl Ester ◽  
High Affinity ◽  
Acid Methyl ◽  
Selective Ligand

scholarly journals Activation of G protein-coupled bile acid receptor, TGR5, induces smooth muscle relaxation via both Epac- and PKA-mediated inhibition of RhoA/Rho kinase pathway

2013 ◽  
Vol 304 (5) ◽  
pp. G527-G535 ◽  
Author(s):  
Senthilkumar Rajagopal ◽  
Divya P. Kumar ◽  
Sunila Mahavadi ◽  
Sayak Bhattacharya ◽  
Ruizhe Zhou ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Kinase Activity ◽  
Muscle Relaxation ◽  
Rho Kinase ◽  
Muscle Cells ◽  
Receptor Activation ◽  
Gastric Smooth Muscle ◽  
Selective Ligand ◽  
Gastric Muscle ◽  
Kinase Pathway

The present study characterized the TGR5 expression and the signaling pathways coupled to this receptor that mediates the relaxation of gastric smooth muscle. TGR5 was detected in gastric muscle cells by RT-PCR and Western blotting. Treatment of cells with the TGR5-selective ligand oleanolic acid (OA) activated Gαs, but not Gαq, Gαi1, Gαi2, or Gαi3, and increased cAMP levels. OA did not elicit contraction, but caused relaxation of carbachol-induced contraction of gastric muscle cells from wild-type mice, but not tgr5−/− mice. OA, but not a selective exchange protein activated by cAMP (Epac) ligand (8-pCPT-2′-O-Me-cAMP), caused phosphorylation of RhoA and the phosphorylation was blocked by the PKA inhibitor, myristoylated PKI, and by the expression of phosphorylation-deficient mutant RhoA (S188A). Both OA and Epac ligand stimulated Ras-related protein 1 (Rap1) and inhibited carbachol (CCh)-induced Rho kinase activity. Expression of RhoA (S188A) or PKI partly reversed the inhibition of Rho kinase activity by OA but had no effect on inhibition by Epac ligand. However, suppression of Rap1 with siRNA blocked the inhibition of Rho kinase by Epac ligand, and partly reversed the inhibition by OA; the residual inhibition was blocked by PKI. Muscle relaxation in response to OA, but not Epac ligand, was partly reversed by PKI. We conclude that activation of TGR5 causes relaxation of gastric smooth muscle and the relaxation is mediated through inhibition of RhoA/Rho kinase pathway via both cAMP/Epac-dependent stimulation of Rap1 and cAMP/PKA-dependent phosphorylation of RhoA at Ser188. TGR5 receptor activation on smooth muscle reveals a novel mechanism for the regulation of gut motility by bile acids.

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