TY - JOUR A1 - Peric, M. A1 - Engels, Bernd A1 - Peyerimhoff, S.D. T1 - Ab initio investigation of the vibronic structure of the C\(_2\)H spectrum Calculation of the hyperfine coupling constants for the three lowest lying electronic states N2 - The hyperfine coupling constants (isotropic hfcc and four Cartesian components of the ani~ tropic tensor) are calculated for all three atoms of C\(_2\)H in its three lowest-lying electronic states at various molecu)ar geometries by means of the ab initio configuration interaction ( MRO.CI) method. The off-diagonal electronic matrix elements involving the two species ofthe A' symmetry are also computed. A diabatic transforrnation is perforrned Jeading to simple geometrical depen· dences of the hyperline coupling constants. KW - Organische Chemie Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-58901 ER - TY - JOUR A1 - Peric, M. A1 - Engels, Bernd A1 - Peyerimhoff, S.D. T1 - Ab initio investigation of the vibronic structure of the C\(_2\)H spectrum Computation of the vibronically-averaged values for the Hyperfine Coupling Constants N2 - The vibronically averaged values for tbe hyperfine coupling constants in the X\(^2 \sum\)-A\(^2 \Pi\) system of the ethynyl radical are computed by means of tbe ab initio metbod calculations. The results point at tbe importance of taking into account the coupling of a1l tbree electronic states in question ( I\(^2\)A', 2\(^2\)A', and 1\(^2\)A") for a reliable explanation of the available experimental findings. The mean values of the hfcc's for K = 0 and 1 levels in \(^{13}\)C\(_2\)H and \(^{13}\)C\(_2\)D in the energy range up to 6000 cm\(^{-1}\) are predicted. KW - Organische Chemie Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-58915 ER - TY - JOUR A1 - Maurer, Bernd A1 - Serfling, Edgar A1 - ter Meulen, Volker A1 - Rethwilm, Axel T1 - Transcription factor AP-1 modulates the activity of the human foamy virus long terminal repeat N2 - The human foamy virus (HFV) contains within the UJ region of its long terminal repeat (L TR) three perfect consensus sequences for the binding of the inducible transcription factor AP-1. Results of DNase I footprint protection and gel retardation assays demonstrated that proteins in extracts of HeLa and BHK-21 cells as weil as bacterially expressed Jun and Fos proteins bind to these AP-1 sites. By conducting transient expression assays using chloramphenicol acetyltransferase plasmids carrying LTR sequences with point-mutated AP-1 sites it was found that the three AP-1 sites contribute to the optimal activity ofthe HFV promoter. It is shown that lnduction of the HFV L TR by 12-O-tetradecanoylphorbol-13-acetate (TPA) and serum factors is mediated through the AP-1 sites. KW - Virologie Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61444 ER - TY - JOUR A1 - Bothe, Katrin A1 - Aguzzi, Adriano A1 - Lassmann, Hans A1 - Rethwilm, Axel A1 - Horak, Ivan T1 - Progressive encephalopathy and myopathy in transgenic mice expressing human foamy virus genes N2 - Transgenie mice carrying the bel region of human foamy retrovirus (HFV) under transcriptional control of its own long terminal repeat expressed tbe transgene in their centrat nervous systems and in smootb and striated muscle tissues. The animals developed a progressive degenerative disease of tbe centrat nervous system and of the striated muscle. Because expression of tbe transgene was dosely correlated witb the appearance of structural damage and inflammatory reactions were scanty, the disease is likely to be caused directly by tbe HFV proteins. These unexpected findings call for a reevaluation of tbe patbogenic potential of HFV in humans. KW - Virologie Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61453 ER - TY - JOUR A1 - Kaupp, Martin A1 - Schleyer, Paul. von Rague A1 - Stoll, Hermann A1 - Preuss, Heinzwerner T1 - The Question of bending of the Alkaline Earth Dihalides MX\(_2\) (M = Be, Mg, Ca, Sr, Ba; X = F, C1, Br, I). An ab Initio Pseudopotential Study N2 - No abstract available KW - Anorganische Chemie Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-60166 ER - TY - JOUR A1 - Kaupp, Martin A1 - Stoll, Hermann A1 - Preuss, Heinzwerner A1 - Kaim, Wolfgang A1 - Stahl, Thomas A1 - van Koten, Gerard A1 - Wissing, Elmo A1 - Smeets, Wilberth J. J. A1 - Spek, Anthony L. T1 - Theoretical and Experimential Study of Diamagnetic and Paramagnetic Products from Thermal and Light-Induced Alkyl Transfer between Zinc or Magnesium Dialkyls and 1,4-Diaza-1,3-butadiene Substrates N2 - No abstract available KW - Anorganische Chemie Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-60173 ER - TY - JOUR A1 - Dörje, F. A1 - Wess, J. A1 - Lambrecht, G. A1 - Tacke, Reinhold A1 - Mutschler, E. A1 - Brann, M. R. T1 - Antagonist binding profiles of five cloned human muscarinic receptor subtypes N2 - A variety of muscarinic antagonists are currently used as tools to pharmacologically subclassify muscarinic receptors into M\(_1\), M\(_2\) and M\(_3\) subtypes. ln the present study I we have determined the affinity proflies of several of these antagonists at five cloned human muscarinic receptors (m1-m5) stably expressed in Chinesehamster ovary cells (CHO-K1). At all five receptorsl the (R)-enantiomers of trihexyphenidyl and hexbutinol displayed considerably higher affinities (up to 525-fold) than their corresponding (S)-isomers. The stereoselectivity ratios [inhibition constant( S)/inhibition constant(R)] for both pairs of enantiomers were lowest at m2 receptors, suggesting that less stringent configurational demands are made by this receptor subtype. The "M\(_1\)-selective" antagonist (R)-trihexyphenidyl displayed high affinities for m1 and m4 receptors. The "M\(_2\)-selective" antagonists himbacinel (±}-5, 11-dihydro-11-1[(2-[(dipropylamino)methyl]-1- piperidinyllethyl)amino]carbonyii-6H-pyrido(213-b)(1 ~4)benzodiazepine- 6-one (AF-DX 384)1 11-(14-[4-(diethylamino)butyl)-1-piperidinyll acetyl)-5~ 11-dihydro-6H-pyrido(2~3-b) (1~4)benzodiazepine-6-one (AQ-RA 741) and (+K11-(12-[(diethylamino)methyl]-1-piperidinyll acetyl)-5~ 11-di-hydro-6H-pyrido(2~3-b)(1,4)benzodiazepine-6-one (AF-OX 250; the (+)-enantiomer of AF-DX 116] exhibited high affinities for m2 and m41 intermediate affinities for m1 and m3 and low affinities for m5 receptors. This selectivity profile was most prominent for AQ-RA 7 41 I which displayed 195- and 129-fold higher affinities for m2 and m4 receptors than for mS receptors. The "M\(_3\)-selective" antagonist (±)-p-fluoro-hexahydro-sila-difenidol hydrochloride (pFHHsiD) exhibited high affinity for m1 I m3 and m4 receptors. 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP) bound with up to 7 -fold higher affinities to m1 I m31 m4 and m5 receptors than to m2 receptors. Although none of the tested antagonists showed more than 2-fold selectivity for one subtype over all other subtypes, each receptor displayed a unique antagonist binding profile. KW - Anorganische Chemie Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64113 ER - TY - JOUR A1 - Waelbroeck, M. A1 - Camus, J. A1 - Tastenoy, M. A1 - Mutschler, E. A1 - Strohmann, C. A1 - Tacke, Reinhold A1 - Lambrecht, G. A1 - Christophe, J. T1 - Binding affinities of hexahydro-difenidol and hexahydro-sila-difenidol analogues at four muscarinic receptor subtypes: constitutional and stereochemical aspects N2 - Hexahydro-sila-difenidoJ and eight analogues behaved as simple cumpetitive inhibitors of eHJN·methyl·scopoJamine binding to homogenates frorn human neuroblastoma NB-OK 1 cells (M\(_1\) sites), rat heart (M\(_2\) sites), rat pancreas (M\(_3\) sites), and rat striatum 'B' sites (M\(_4\) sites). Pyrrolidino- and hexamethyleneimino analogues showed the same sekctivity profile as the parent compound. Hexahydro-sila-difenidol methiodide and the methiodide of p-fluoro-hexahydro·sila-difenidol had a fügher affinity but a lower selectivity than the tertiary amines. Compounds containing a p·methoxy, p-chJoro or p-fluoro substituent in the phenyl ring of hexahydro-sila-difenidol showed a qualitative)y similar selectivity profile as the parent compound (i.e., M\(_1\)= M\(_3\) = M\(_4\) >M\(_2\) ), but up to 16-fold lower affinities. o-Methoxy-hexahydro-sila-difenidol has a lower affinity than hexahydro-sila-difeni.:!o! at the four binding sites. lts selectivity profile (M\(_4\) > M\(_1\), M\(_3\) > M\(_2\) ) was different from hexahydro-sila-difenidol. Replacement of the centrat silicon atom of hexahydro-sila-difenidol, p-fluoro-hexahydro-sila-difenidol and thdr quatemary (N-methylated) analogues by a carbon atom did not change their binding affinities significantly. The iour muscarinic receptors showed a higher affinity for the (R)- than for the (S)-enantiomers of hexahydro-difenidol, p-fluorohexahydro-difenidol and their methiodides. The stereoselectivity varied depending on the receptor subtype and drug considered. KW - Anorganische Chemie KW - Muscarinic receptor antagonists (selective) KW - Hexahydro-sila-difenidol analogues KW - p-Fluoro-hexahydro-sila-difenidol KW - Stereoselectivity Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64128 ER - TY - JOUR A1 - Waelbroeck, M. A1 - Camus, J. A1 - Tastenoy, M. A1 - Mutschler, E. A1 - Strohmann, C. A1 - Tacke, Reinhold A1 - Lambrecht, G. A1 - Christophe, J. T1 - Stereoselectivity of (R)- and (S)-hexahydro-difenidol binding to neuroblastoma M\(_1\), cardiac M\(_2\), pancreatic M\(_3\), and striatum M\(_4\) muscarinic receptors N2 - (R)-Hexahydro-difenidol has a higher affinity for M\(_1\) receptors in NB-OK 1 cells, pancreas M\(_3\) and striatum M\(_4\) receptors (pKi 7.9 to 8.3) than for cardiac M2 receptors (pKi 7 .0). (8)-Hexahydro-difenidol, by contrast, is nonselective (pKi 5.8 to 6.1). Our goal in the present study was to evaluate the importance ofthe hydrophobic phenyl, and cyclohexyl rings of hexahydro-difenidol for the stereoselectivity and reeeptor selectivity of hexahydro-difenidol binding to the four muscarinic receptors. Our results indieated that replacement of the phenyl ring of hexahydro-difenidol by a cyclohexyl group <~ dicyclidol) and ofthe cyclohexyl ring by a phenyl moiety <~ difenidol) indueed a !arge (4- to 80-fold) decrease in binding affinity for all musearlnie receptors. Difenidol had a signifieant preference for M\(_1\) , M\(_3\) , and M\(_4\) over M\(_2\) receptors; dicyclidol, by eontrast, had a greater affinity for M\(_1\) and M\(_4\) than for M\(_2\) and M\(_3\) receptors. The binding free energy deerease due to replacement ofthe phenyl and the cyelohexyl groups of(R)-hexahydro-difenidol by, respectively, a eyclohexyl and a phenyl moiety was almostadditive in the ease of M\(_4\) (striatum) binding sites. In the ease ofthe cardiac M\(_2\), pancreatic M\(_3\) , or NB-OK 1 M\(_1\) receptors the respective binding free energies were not eompletely additive. These results suggest that the four (R)-hexahydro-difenidol ''binding moieties" (phenyl, cyclohexyl, hydroxy, and protonated amino group) cannot simultaneously form optimal interaetions with the M\(_1\), M\(_2\), and M\(_3\) muscarinic receptors. When eaeh of the hydrophobic groups is modified, the position of the whole molecule, relative to the four subsites, was changed to allow an optimal overall interaction with the musearlnie receptor. KW - Anorganische Chemie KW - hexahydro-difenidol enantiomers KW - muscarinic receptor subtypes KW - stereoselective interaction KW - difenidol KW - dicyclidol Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64135 ER - TY - JOUR A1 - Strohmann, C. A1 - Bauerecker, S. A1 - Cammenga, H. K. A1 - Jones, P. G. A1 - Mutschler, E. A1 - Lambrecht, G. A1 - Tacke, Reinhold T1 - Enantiomers of the muscarinic antagonist 1-cyclohexyl-1-(4-fluorophenyl)-4-piperidino-1-butanol (p-fluoro-hexahydro-difenidol): synthesis, absolute configuration, and enantiomeric purity N2 - The enantiomers of the antimuscarinic agent 1-cyclohexyl-1- (4-fluorophenyl)-4-piperidino-1-butanol [(R)- and (S)-p-fluorohexahydro- difenidol] ((R)- and (S)-2a] and their methiodides (R)- 3 and (S)-3 were prepared with high enantiomeric purity. (R)- 2a and (S)-2a (isolated as hydrochlorides) were obtained by catalytic hydrogenation (Pd/C contact) of the corresponding enantiomers of 1-cyclohexyl-1-( 4-fl uorophen yl)-4-piperidino- 2-butyn-1-ol [(R)- and (S)-4]. Reaction of (R)-2a and (S)-2a with rnethyl iodide led to (R)-3 and (S)-3, respectively. The unsaturated precursors (R)- and (S}-4 (enantiorneric purity ~ 99.80 and ~99.94% e.e.; calorimetric analysis) were prepared by res-sepaolution of rac-4 [available from 4-FC\(_6\)H\(_4\)C(O)C\(_6\)H\(_{11}\) by reaction with LiC ~ CCH\(_2\)NC\(_5\)H\(_{10}\)] using (R)- and (S)-mandelic acid as resolving agents. The absolute configurations of the (R) and (S) enantiomers of 2a, 3, and 4 were determined by an X-ray crystal-structure analysis of (S)-5, the methiodide of (S)-4. (R)- 2a and (R)-3 exhibit a higher affinity for muscarinic M1, M2, M3, and M4 receptors (by up to two orders of magnitude) than their corresponding antipodes (S)-2a and (S)-3, the degree of stereoselectivity depending on the receptor subtype involved. (R)-2a represents a useful tool for rnuscarinic receptor research (affinity profile: M1 ~ M3 ~ M4 > M2). KW - Anorganische Chemie KW - Difenidol KW - p-fluoro-hexahydro- KW - enantiomers of / Muscarinic receptors KW - subtypes of Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64144 ER - TY - JOUR A1 - Hengelsberg, H. A1 - Tacke, Reinhold A1 - Fritsche, K. A1 - Syldatk, C. A1 - Wagner, F. T1 - Synthesis and enantioselective enzymatic hydrolysis of rac-dimethylphenyl[1-(phenylacetamido)- ethyl]silane N2 - Racemic dimethylphenyl(l-(phenylacetamido)ethyl)silane [rac-5) has been made by a four-step synthesis starting from (chloromethyl)dimethylphenylsilane [PhMe\(_2\)SiCH2Cl (1) ~ PhMe\(_2\)SiCH(Cl)Me (rac-2) - PhMe\(_2\)SiCH(l)Me (rac-3) - PhMe2SiCH(NH2)Me (rac-4) ~ PhMe\(_2\)SiCH[N(H)C(O)CH\(_2\)Ph]Me ( rac-5); total yield 41% ). Enantioselective enzymatic hydrolysis of rac-5, catalyzed by immobilized penicillin G acylase (E.C. 3.5.1.11) from Escherichia coli 5K (pHM 12), gave (R)-(1- aminoethyl)dimethylphenylsilane [( R )-4] in 40% yield with an enantiomeric purity of 92% ee. KW - Anorganische Chemie Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64153 ER - TY - JOUR A1 - Tacke, Reinhold A1 - Mahner, K. A1 - Strohmann, C. A1 - Forth, B. A1 - Mutschler, E. A1 - Friebe, T. A1 - Lambrecht, G. T1 - Cyclohexyl(4-fluorophenyl)(3-piperidinopropyl)silanol (p-fluoro-hexahydro-sila-difenidol, p-F-HHSiD) and derivatives: synthesis and antimuscarinic properties N2 - Four different syntheses of the potent and selective muscanruc antagonist cyclohexyl( 4- fluorophenyl)(3-piperidinopropyl)silanol ( p-fluoro-hexahydro-sila-difenidol, p-F-HHSiD (2b); isolated as hydrochloride 2b· HCl) are described (starting materials: (CH\(_3\)O)\(_2\)SiCH\(_2\)CH\(_2\)CH\(_2\)Cl and Si(OCH\(_3\))\(_4\) ). In addition, the synthesis of the corresponding carbon analogue p-fluoro-hexahydro-difenidol ( p-F-HHD (2a); isolated as 2a· HCI) and the syntheses of three p-F-HHSiD derivatives (3-5), with a modified cyclic amino group, are reported (3: piperidinojpyrrolidino exchange, isolated as 3· HCI; 4: piperidinoj hexamethylenimino exchange, isolated as 4 · HCl; 5: quaternization of 2b with methyl iodide). The chiral compounds 2a, 2b, 3, 4 and 5 were prepared as racemates. In functional pharmacological studies, 3-5 behaved as simple competitive antagonists at musearlnie Ml receptors in rabbit vas deferens, M2 receptors in guinea-pig atria, and M3 receptors in guinea-pig ileal smooth rnuscle. The pyrrolidino (3) and hexamethylenimino (4) analogues of the parent drug p-F-HHSiD (2b) displayed the highest affinity for Ml and M3 receptors (pA\(_2\) values: 7.0-7.4) but exhibited lower affinity for cardiac M2 receptors (pA\(_2\) : 5.9 and 6.0). Their affinity profile (Ml- M3 > M2) is different from that of p-F-HHSiD (2b) (M3 > Ml > M2), but qualitatively very similar tothat of p-F-HHD (2a). The methiodide 5 exhibited the highest affinity for Ml receptors (pA\(_2\) : 8.5) but lower affinity for M2 and M3 receptors by factors of 5.6 and 3.6, respectively. KW - Anorganische Chemie Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64162 ER - TY - JOUR A1 - Haas, Albert A1 - Brehm, Klaus A1 - Kreft, Jürgen A1 - Goebel, Werner T1 - Cloning, characterization, and expression in Escherichia coli of a gene encoding Listeria seeligeri catalase, a bacterial enzyme highly homologous to mammalian catalases N2 - A gene coding for catalase (hydrogen-peroxide:hydrogen-peroxide oxidoreductase; EC 1.11.1.6) of the grain-positive bacterium Listeria seeligeri was cloned from a plasmid library of EcoRI-digested chromosomal DNA, with Escherichia coli DHSa as a host. The recombinant catalase was expressed in E. coli to an enzymatic activity approximately SO times that of the combined E. coli catalases. The nucleutide sequence was determined, and the deduced amino acid sequence revealed 43.2% amino acid sequence identity between bovine liver catalase and L. seeligeri catalase. Most of the amino acid residues which are involved in catalytic activity, the formation of the active center accession channel, and heme binding in bovine liver catalase were also present in L. seeligeri catalase at the corresponding positions. The recombinant protein contained 488 amino acid residues and had a calculated molecular weight of 55,869. The predicted isoelectric point was 5.0. Enzymatic and genetic analyses showed that there is most probably a single catalase of this type in L. seeligeri. A perfect 21-bp inverted repeat, which was highly homologous to previously reported binding sequences of the Fur (ferric uptake regulon) protein of E. coli, was detected next to the putative promoter region of tbe L. seeligeri catalase gene. KW - Biologie Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-60536 ER - TY - JOUR A1 - Markgraf, J. H. A1 - Cort, J. R. A1 - Davis, H. A. A1 - Lindeman, N. I. A1 - Myers, C. R. A1 - Kraft, A. A1 - Christl, Manfred T1 - Strained Heterocyclic Systems. 20. Basicities of Bicyclic Quinoxalines N2 - No abstract available KW - Organische Chemie Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-58584 ER - TY - JOUR A1 - Schülein, Ralf A1 - Kreft, Jürgen A1 - Gonski, Sigrid A1 - Goebel, Werner T1 - Preprosubtilisin Carlsberg processing and secretion is blocked after deletion of amino acids 97-101 in the mature part of the enzyme N2 - During an investigation into the substrate specificity and processing of subtilisin Carlsberg from Bacillus licheniformis, two major independent findings were made: (i) as has been shown previously, a stretch of five amino acids (residues 97-101 of the mature enzyme) that loops out into the binding cleft is involved in substrate binding by subtilisin Carlsberg. In order to see whether this loop element also determines substrate specificity, the coding region for these five amino acids was deleted from the cloned gene for subtilisin Carlsberg by site-directed mutagenesis. Unexpectedly the resulting mutant preproenzyme (P42c, Mr=42 kDa) was not processed to the mature form (Mr = 30 kDa) and was not released into the medium by a proteasedeficient B. subtilis host strain; rather, it accumulated in the cell membrane. This result demonstrates that the integrity of this loop element, which is very distant from the processing cleavage sites in the preproenzyme, is required for secretion of subtilisin Carlsberg. (ii) In culture supernatants from B. subtilis harbouring the cloned wild-type subtilisin Carlsberg gene the transient appearance (at 0-3 h after onset of stationary phase) of a processing intermediate (P38c, Mr = 38 kDa) oftbis protease could be demonstrated. P38c very probably represents a genuine proform of subtilisin Carlsberg. KW - Biologie KW - Bacillus KW - Proenzyme KW - Subtilisin maturation KW - Site-directed mutagenesis KW - Subtilisin Carlsberg Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-60577 ER - TY - JOUR A1 - Bentley, T. W. A1 - Christl, Manfred A1 - Norman, S. J. T1 - Methanesulfonate/p-Nitrobenzoate and p-Toluenesulfonate/p-Nitrobenzoate Rate Ratios. Solvolyses of 1-Adamantyl and Benzhydryl Substrates N2 - No abstract available KW - Organische Chemie Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-58599 ER - TY - JOUR A1 - Vortkamp, A. A1 - Thias, U. A1 - Gessler, Manfred A1 - Rosenkranz, W. A1 - Kroisel, P. M. A1 - Tommerup, N. A1 - Kruger, G. A1 - Gotz, J. A1 - Pelz, L. A1 - Grzeschik, Karl-Heinz T1 - A somatic cell hybrid panel and DNA probes for physical mapping of human chromosome 7p N2 - No abstract available KW - Biochemie Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59217 ER - TY - JOUR A1 - Jaiswal, Neelam A1 - Lambrecht, Günter A1 - Mutschler, Ernst A1 - Tacke, Reinhold A1 - Malik, Kafait U. T1 - Pharmacological characterization of the vascular muscarinic receptors mediating relaxation and contraction in rabbit aorta JF - Journal of Pharmacology and Experimental Therapeutics N2 - Studies were performed in the rabbit aortic rings, precontracted with norepinephrine, to determine the subtype(s) of muscarinic receptors involved in endothelium-dependent relaxation and contraction in the absence of endothelium elicited by cholinergic stimuli. Acetylcholine (ACh) and arecaidine propargyl ester (APE), a M2 and M3 agonist, produced a dose-dependent relaxation and contraction in endothelium-intact and endothelium-denuded rabbit aortic rings, respectively. Both of these responses were blocked by the muscarinic receptor antagonist atropine. M1 selective agonist McN-A-343 [4-[N-(3-chlorophenyl)carbamoyloxy]-2-butinyltrimethylammonium+ ++ chloride] did not produce any effect on the tone of precontracted aortic rings. ACh- and APE-induced relaxation in aortic rings with intact endothelium was selectively blocked by M3 receptor antagonists hexahydrosila-difenidol and p-fluoro-hexahydro-sila-difenidol (pA2 of 7.84 and 7.18) but not by M1 antagonist pirenzepine or M2 receptor antagonists AF-DX 116 [11-(2-[(diethylamino)methyl]- 1-piperidinyl]acetyl)-5, 11-dihydro-6H-pyrido-[2,3-b][1,4]-benzo-diazepin-6-one] and methoctramine. ACh- and APE-induced contraction was inhibited by M2 receptor antagonists AF-DX 116 and methoctramine (pA2 of 7.11 and 6.71) but not by pirenzepine, hexahydro-sila-difenidol or p-fluoro-hexahydro-sila-difenidol. ACh- and APE-induced relaxation or contraction were not altered by nicotinic receptor antagonist hexamethonium or cyclooxygenase inhibitor indomethacin. These data suggest that relaxation elicited by cholinergic stimulin in endothelium-intact aortic rings is mediated via release of endothelium-derived relaxing factor consequent to activation of M3 receptors located on endothelial cells, whereas the contraction in aortic rings denuded of their endothelium is mediated via stimulation of M2 receptors located on smooth muscle cells. KW - (4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethylammonium chloride/pharmacology KW - acetylcholine KW - animals KW - antihypertensive agents / pharmacology KW - aorta, abdominal / drug effects KW - aorta, abdominal / physiology KW - aorta, abdominal / ultrastructure KW - arecoline/analogs & derivatives KW - arecoline KW - atropine KW - diamines KW - endothelium, vascular / drug effects KW - endothelium, vascular / physiology KW - hexamethonium KW - hexamethonium compounds KW - indomethacin KW - male KW - muscarinic antagonists KW - muscle contraction KW - muscle relaxation KW - norepinephrine KW - parasympatholytics KW - piperidines KW - pirenzepine KW - rabbits Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128358 VL - 258 IS - 3 ER - TY - JOUR A1 - Gigstad, Kenneth M. A1 - Ricci JR., John S. A1 - Markgraf, J. Hodge A1 - Christl, Manfred A1 - Kraft, Arno T1 - Strained Heterocyclic Systems : 18. Structure of 1,2,3-Methylidyne-2,3-dihydro-1H-cyclopenta[b]quinoxaline N2 - No abstract available Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-41645 SN - 0108-2701 ER - TY - CHAP A1 - Hommers, Wilfried A1 - Anderson, Norman H. T1 - Moral algebra of harm and recompense N2 - No abstract available KW - Informationsverarbeitung / Kognition Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-44046 ER -