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  • 1
    ISSN: 1432-1912
    Keywords: [3H]5-HT binding sites ; 5-HT autoreceptors ; Presynaptic receptors ; Rat cerebral cortex ; Canine saphenous vein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The affinities of 16 5-hydroxytryptamine (5-HT) receptor agonists (indole derivatives) and 7 5-HT receptor antagonists for [3H]5-hydroxytryptamine ([3H]5-HT) binding sites in rat cerebral cortex membranes were determined. In addition, the potencies of the agonists for inhibiting the electrically induced tritium overflow from rat brain cortex slices preincubated with [3H]5-HT and from canine saphenous veins preincubated with [3H]noradrenaline were measured. Furthermore, the potencies of the indole derivatives for inducing contractile responses of canine saphenous veins were recorded. In addition, the interaction of the antagonists with unlabelled 5-HT at the 5-HT autoreceptor was studied in rat brain cortex slices. There was a good correlation between the binding affinities of the indole derivatives for the [3H]5-HT sites of rat brain cortex membranes and their potencies for inhibiting the evoked tritium overflow from both rat brain cortex slices and strips of canine saphenous vein. Comparison of the inhibition constants derived from the overflow experiments in both tissues again revealed a high correlation coefficient while there was only weak correlation between the binding affinities in rat brain cortex and the contractile potencies of the drugs in canine saphenous vein strips. When 5-HT receptor antagonists were investigated, metitepin and metergoline showed moderate affinities for the 5-HT autoreceptors in rat brain cortex slices, whereas quipazine had only weak affinity, and ketanserin, metoclopramide, cinanserin and cyproheptadine exhibited no antagonistic property. In binding experiments, the competition curves of most 5-HT receptor antagonists were biphasic, suggesting that the [3H]5-HT binding sites are heterogeneous. The affinities of the antagonists to the low affinity binding sites were roughly in accordance with their affinities for the 5-HT autoreceptors determined in release experiments. It is concluded that [3H]5-HT binding sites, presynaptic 5-HT autoreceptors in the rat brain cortex and inhibitory presynaptic 5-HT receptors on sympathetic nerve endings in the canine saphenous vein possess common pharmacological properties. In the rat brain cortex, the 5-HT1 sites are not homogeneous. Part of the [3H]5-HT binding sites (low affinity sites rather than high affinity sites) may be localized on the serotoninergic neurones and, hence, be identical with the serotonin autoreceptors. The results are also compatible with the suggestion that there may exist even more than two subtypes of [3H]5-HT1 binding sites in the rat brain cortex.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 723-729 
    ISSN: 0044-2313
    Keywords: Dimethyltin dithiosquarate benzene solvate ; Dimethyltin dithiosquarate-dimethylsulfoxide adduct ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dimethyltin Dithiosquarate: The Crystal Structure of the Benzene Solvate and of the Dimethylsulfoxide Adduct(CH3)2SnS2C4O2 · 1/3 C6H6 (I) crystallizes in the orthorhombic space group Pnma. a = 14.393(2), b = 21.668(3), c = 10.424(1) Å, Z = 12.(CH3)2SnS2C4O2 · (CH3)2SO (II) is monoclinic, space group P21/n, a = 9.918(5), b = 12.028(6), c = 12.223(6) Å, β = 108.82(3)°, Z = 4.In I there are two independent dimethyltin dithiosquarate molecules. But in both molecules the Sn atoms display weak coordinative bonds to two O atoms of adjacent dithiosquarate groups. The distances amount 2.873 Å (2×), resp. 2.678 and 2.831 Å. The coordination number of tin becomes 6 and the structure gets connected in three dimensions.In II dimethylsulfoxide is bound with the O atom to Sn (2.345 Å) and the result is a distorted trigonal bipyramid. There a more distant O atom (2.944 Å) leads to a connection of the molecules to a ribbon. The changes of the geometrical parameters are described, which result from the progressive approach of the one O atom.
    Notes: (CH3)2SnS2C4O2 · 1/3 C6H6 (I) kristallisiert in der orthorhombischen Raumgruppe Pnma; a = 14,393(2); b = 21,668(3); c = 10,424(1) Å; Z = 12.(CH3)2SnS2C4O2 · (CH3)2SO (II) ist monoklin, Raumgruppe P21/n; a = 9,918(5); b = 12,028(6); c = 12,223(6) Å; β = 108,82(3)°; Z = 4.In I liegen zwei kristallographisch unabhängige Dimethyl-zinndithioquadratat-Moleküle vor. Bei beiden weisen jedoch die Sn-Atome schwache koordinative Bindungen zu zwei O-Atomen benachbarter Dithioquadratat-Gruppen auf. Die Abstände betragen 2,873 Å (2×) bzw. 2,678 und 2,831 Å. Dadurch erhält Zinn die Koordinationszahl 6, und es ergibt sich eine dreidimensional vernetzte Struktur.In II ist Dimethylsulfoxid über das O-Atom an Sn gebunden (2,345 Å), und es liegt eine verzerrte trigonale Bipyramide vor. Ein weiter entferntes O-Atom (2,944 Å) bewirkt hier die Vernetzung der Moleküle zu einem Band. Die Veränderungen der geometrischen Parameter als Folge der fortschreitenden Annäherung des einen O-Atoms werden beschrieben.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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