@incollection{LohseKlotzMaureretal.1990, author = {Lohse, Martin J. and Klotz, Karl-Norbert and Maurer, K. and Ott, I. and Schwabe, Ulrich}, title = {Effects of adenosine on mast cells}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86101}, publisher = {Universit{\"a}t W{\"u}rzburg}, year = {1990}, abstract = {No abstract available}, subject = {Adenosin}, language = {en} } @incollection{SpielmannArendKlotzetal.1990, author = {Spielmann, W.-S. and Arend, L. J. and Klotz, Karl-Norbert and Schwabe, U.}, title = {Adenosine receptors and singnaling in the kidney}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86114}, publisher = {Universit{\"a}t W{\"u}rzburg}, year = {1990}, abstract = {No abstract available.}, subject = {Adenosinrezeptor}, language = {en} } @incollection{SpielmannArendKlotzetal.1991, author = {Spielmann, W. S. and Arend, L. J. and Klotz, Karl-Norbert and Schwabe, U.}, title = {Adenosine control of the renal Collecting tubule: receptors and signaling}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86129}, publisher = {Universit{\"a}t W{\"u}rzburg}, year = {1991}, abstract = {No abstract available.}, subject = {Adenosin}, language = {en} } @article{LohseKlotzSchwabe1986, author = {Lohse, Martin J. and Klotz, Karl-Norbert and Schwabe, Ulrich}, title = {Effectes of temperature and membrane phase transitions on ligand binding to a2-receptors of human platelets}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86023}, year = {1986}, abstract = {The binding of agonists and antagonists to a2-adrenergic receptors of human platelets was studied. The receptors showed homogeneaus affinities for antagonists but two affinity states for the agonist (-)-epinephrine, which were modulated by guanine nucleotides. Van't Hoffplots of antagonist binding had a break point at about 18° and considerable diversity between 18° and 0°. Agonist binding to both affinity states showed a similar break point; agonist binding to the high affinity state was characterized by a large entropy component compared to the low affinity state. This entropy component was reduced at higher concentrations of sodium, indicating that it may be due to Iiberation of sodium ions. Measurements of the fluorescence of 1-anilin-8-naphthalenesulfonate showed thermotropic phase transitions of theplatelet membranes at about 17°. The transition temperature was decreased to about 12° by addition of 1 0 mM octanoic acid. Octanoic acidalso shifted the break points of the van't Hoffplot of antagonist and low affinity agonist binding from 18° to 12°. High affinity agonist binding, however, remained unchanged. It is concluded that agonist-specific thennodynamic characteristics of ligand binding to a2-receptors of human platelets can only be investigated by regarding differences between high and low affinity agonist binding. These differences include an entropy increase upon Iigand binding, which is in part due to enhanced liberation of sodium ions, and a loss of sensitivity to fluidity changes in the outer layer of the plasma membrane.}, subject = {Molekularpharmakologie}, language = {en} } @article{LohseKlotzSchwabe1986, author = {Lohse, Martin J. and Klotz, Karl-Norbert and Schwabe, Ulrich}, title = {Agonist photoaffinity labeling of A1 adenosine receptors: Persistent activation reveals spare receptors}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-87966}, year = {1986}, abstract = {No abstract available.}, subject = {Pharmazie}, language = {en} } @article{MeierGrossKlotzetal.1989, author = {Meier, Friedegund and Gross, Eva and Klotz, Karl-Norbert and Ruzicka, Thomas}, title = {Leukotriene B4 receptors on neutrophils in patients with psoriasis and atopic exzema}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86265}, year = {1989}, abstract = {Polymorphonuclear leukocyte (PMNL) infiltration is an important characteristic in psoriatic lesions. Elevated concentrations of the chemoattractant eicosanoid leukotriene B4 (L TB4) are present in psoriatic skin. Its chemotactic activity is mediated via high affinity receptors on PMNL. The goal of our work was to ascertain whether PMNL infiltration in psoriasis can be accounted for by functional abnormalities of the circulating PMNL due to alterations in the LTB4 receptor density or affinity (or both). No significant difference was found between patients with psoriasis, healthy controls and patients with another inflammatory dermatosis (atopic eczema) with regard to the binding parameters of LTB4 receptors on PMNL. Our findings suggest that PMNL accumulation in psoriatic skin may be the result of an excess of cutaneous hemoattractant rather than the increased readiness of psoriatic PMNL to migrate towards L TB4 due to altered LTB4 receptor density or affinity.}, subject = {Dermatologie}, language = {en} } @incollection{KlotzKeilZimmeretal.1989, author = {Klotz, Karl-Norbert and Keil, Roger and Zimmer, Franz-Josef and Schwabe, Ulrich}, title = {Modulation of (\SH) DPCPX binding to membrane-bound ans solubilized A1 adenosine receptors by guanine nucleotides}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86153}, publisher = {Universit{\"a}t W{\"u}rzburg}, year = {1989}, abstract = {No abstract available}, subject = {Adenosinrezeptor}, language = {en} } @article{JesaitisKlotz1993, author = {Jesaitis, A. J. and Klotz, Karl-Norbert}, title = {Cytoskeletal regulation of chemotactic receptors: Molecular complexation of N-formyl peptide receptors with G proteins and actin}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-79673}, year = {1993}, abstract = {Signal transduction via receptors for N-formylmethionyl peptide chemoattractants (FPR) on human neutrophils is a highly regulated process. It involves direct interaction of receptors with heterotrimeric G-proteins and may be under thc control of cytoskeletal clemcnts. Evidencc exists suggesting that thc cytoskeleton and/or the membrane ske1eton determines the distribution of FPR in the plane of the plasma membrane, thus controlling FPR accessibility to different protcins in functionally distinct membrane domains. In desensitized cells, FPR are restricted to domains which are depleted of G proteins but enriched in cytoskeletal proteins such as actin and fodrin. Thus, the G protein signal transduction partners of FPR become inacccssible to the agonist-occupied receptor, preventing cell activation. We are investigating the molecular basis for the interaction of FPR with the membrane skeleton, and our results suggest that FPR, and possibly other receptors, may directly bind to cytoskeletal proteins such as actin.}, subject = {Immunologie}, language = {en} } @article{GonzalezCaleroCuberoKlotz1991, author = {Gonzalez-Calero, G. and Cubero, A. and Klotz, Karl-Norbert}, title = {Characterization and photoaffinity labeling of A1 adenosine receptors in coated visicles form bovine brain}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86004}, year = {1991}, abstract = {The antagonist (3 II ) DPCPX exhi bitcd a Kd of 0. 4 nM at coalcd vcsicles from bovine brain. Agonist compelition for ( 3 11) DPCPX bind in~ revcaled two affini ty slales for gonists. The pholoaffinity probe I25 I -AHPIA specifically labelled a band with a molecular weight of 35 Kd.}, subject = {Pharmakologie}, language = {en} } @article{VazquezRodriguezVilarKachleretal.2020, author = {Vazquez-Rodriguez, Saleta and Vilar, Santiago and Kachler, Sonja and Klotz, Karl-Norbert and Uriarte, Eugenio and Borges, Fernanda and Matos, Maria Jo{\~a}o}, title = {Adenosine receptor ligands: coumarin-chalcone hybrids as modulating agents on the activity of hARs}, series = {Molecules}, volume = {25}, journal = {Molecules}, number = {18}, issn = {1420-3049}, doi = {10.3390/molecules25184306}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-213165}, year = {2020}, abstract = {Adenosine receptors (ARs) play an important role in neurological and psychiatric disorders such as Alzheimer's disease, Parkinson's disease, epilepsy and schizophrenia. The different subtypes of ARs and the knowledge on their densities and status are important for understanding the mechanisms underlying the pathogenesis of diseases and for developing new therapeutics. Looking for new scaffolds for selective AR ligands, coumarin-chalcone hybrids were synthesized (compounds 1-8) and screened in radioligand binding (hA\(_1\), hA\(_{2A}\) and hA\(_3\)) and adenylyl cyclase (hA\(_{2B}\)) assays in order to evaluate their affinity for the four human AR subtypes (hARs). Coumarin-chalcone hybrid has been established as a new scaffold suitable for the development of potent and selective ligands for hA\(_1\) or hA\(_3\) subtypes. In general, hydroxy-substituted hybrids showed some affinity for the hA\(_1\), while the methoxy counterparts were selective for the hA\(_3\). The most potent hA\(_1\) ligand was compound 7 (K\(_i\) = 17.7 µM), whereas compound 4 was the most potent ligand for hA\(_3\) (K\(_i\) = 2.49 µM). In addition, docking studies with hA\(_1\) and hA\(_3\) homology models were established to analyze the structure-function relationships. Results showed that the different residues located on the protein binding pocket could play an important role in ligand selectivity.}, language = {en} }