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  • 1
    Electronic Resource
    Electronic Resource
    5-Hydroxytryptamine4 receptors mediate relaxation of the rat oesophageal tunica muscularis mucosae (1991)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 343 (1991), S. 439-446 
    Details
    ISSN: 1432-1912
    Keywords: 5-HT4 ; Oesophagus ; Rat ; ICS 205–930 ; Benzamides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The present study was designed to characterize an “atypical” 5-hydroxytryptamine (5-HT) receptor mediating relaxation of the rat oesophageal tunica muscularis mucosae. All experiments were performed under equilibrium conditions, using pargyline to inhibit the oxidative deamination of indoleamines, and cocaine and corticosterone to inhibit neuronal and extraneuronal uptake. Under these conditions 5-HT (0.3–1000 nmol/l) produced a concentration-dependent relaxation of carbachol-induced tension. The concentration-effect curve to 5-HT was unaffected by potent antagonists for 5-HT1, 5-HT2, 5-HT3 and so called 5-HT1P receptors (metergoline, methysergide, ketanserin, ondansetron, N-acetyl-5-hydroxytryptophyl-5-hydroxytryptophan amide), but was antagonized competitively by ICS 205–930 (pA2 = 6.7). Responses to 5-HT were mimicked by other indoleamines and substituted benzamides with the following order of potency: 5-HT ≥ 5-methoxytryptamine 〉 cisapride = α-methyl-5-HT = (S)-zacopride = renzapride 〉 (RS)-zacopride 〉 5-carboxamido-tryptamine = metoclopramide = (R)-zacopride 〉 tryptamine 〉 2-methyl-5-HT. ICS 205–930 afforded similar pA2 values (6.0–6.7) against each agonist, indicating a common site of action. Concentration-effect curves to 5-HT were not affected by tetrodotoxin or indomethacin, sugesting that 5-HT-induced relaxation of the tunica muscularis mucosae was mediated via a postjunctional receptor, independent of endogenous prostanoids. The pharmacological profile of the 5-HT receptor in the rat oesophageal tunica muscularis mucosae correlates well with the 5-HT4 receptor characterized recently in both the CNS and gastro-intestinal tract.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00169544
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  • 2
    Electronic Resource
    Electronic Resource
    Vasoconstrictor and norepinephrine potentiating action of 5-hydroxykynuramine in the isolated perfused rat kidney: involvement of serotonin receptors and alpha1-adrenoceptors (1984)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 328 (1984), S. 154-159 
    Details
    ISSN: 1432-1912
    Keywords: 5-Hydroxytryptamine ; Serotonin receptors ; 5-Hydroxykynuramine ; Alpha1-adrenoceptors ; Perfused rat kidney
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Kynuramines are endogenously occurring diamines derived from tryptophan. In the present study, we have compared the pharmacological actions of 5-hydroxykynuramine (5-OH-K) with kynuramine and 5-hydroxytryptamine (5-HT) on vascular resistance changes and responsiveness to adrenergic stimuli in the isolated perfused rat kidney. 5-OH-K was found to mimic the actions of 5-HT in that it produced vasoconstriction, potentiation of alpha1-adrenoceptor-mediated responses to norepinephrine (NE) and periarterial nerve stimulation and displaced specific [3H]spiroperidol binding from rat cortical membranes. With regard to all parameters measured, 5-OH-K was about 15-times less active than 5-HT. Vascular responses to 5-OH-K and 5-HT were inhibited noncompetitively by ketanserin and cyproheptadine. Unlike 5-OH-K, kynuramine, failed to evoke vasoconstriction and Inhibited vascular responses to NE via alpha1-adrenoceptors. Thus, kynuramine lacks serotonin receptor agonist activity but possesses alphaI-adrenoceptor blocking properties. In contrast, 5-OH-K potentiates NE and acts as a serotonin agonist. The present results raise the possibility that kynuramine and 5-OH-K might act as endogenous modulators of serotonergic and adrenergic mechanisms in the renal vascular bed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00512065
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  • 3
    Electronic Resource
    Electronic Resource
    5-Methoxytryptamine and 2-methyl-5-hydroxytryptamine-induced desensitization as a discriminative tool for the 5-HT3 and putative 5-HT4 receptors in guinea pig ileum (1990)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 342 (1990), S. 9-16 
    Details
    ISSN: 1432-1912
    Keywords: 5-HT4 ; 5-HT3 ; Desensitization ; 5-Methoxytryptamine ; 2-Methyl-5-HT
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Agonist-induced desensitization has been utilized to discriminate and independently “isolate” the neuronal excitatory receptors to 5-hydroxytryptamine (5-HT) in the guinea pig ileum (5-HT3 and putative 5-HT4 receptors). Electrically stimulated longitudinal muscle myenteric plexus preparations, and non-stimulated segments of whole ileum were used. Exposure to 5-methoxytryptamine (10 μmol/l) inhibited completely responses to 5-HT at the putative 5-HT4 receptor without affecting 5-HT3-mediated responses. Conversely, exposure to 2-methyl-5-HT (10 μmol/l) inhibited completely responses to 5-HT at the 5-HT3 receptor without affecting putative 5-HT4-mediated responses. The inhibition with 5-methoxytryptamine and 2-methyl-5-HT, either alone or in combination, appeared selective as responses to KCI, DMPP, carbachol, histamine, and substance P were unaffected or only very slightly modified. Furthermore, the pA2 values for ICS 205–930 at the putative 5-HT4 (pA2 = 6.2 to 6.5) and 5-HT3 (pA2 = 7.6 to 8.1) receptors (estimated in the presence of 2-methyl-5HT and 5-methoxytryptamine, respectively) were consistent with those estimated in the absence of desensitization. 5-Methoxytryptamine, but not 2-methyl-5-HT, suppressed completely but reversibly the concentration-effect curve to renzapride, suggesting that responses to this agent are mediated exclusively via agonism at the putative 5-HT4 receptor. It is concluded that 5-methoxytryptamine and 2-methyl-5-HT can be utilized as selective probes to discriminate the putative 5-HT4 receptor from the 5-HT3 receptor in guinea pig ileum. This finding is of importance as no selective antagonist exists for the putative 5-HT4 receptor. Furthermore, the presently described method of agonist-induced desensitization and 5-HT receptor discrimination may be useful for the identification and characterization of the putative 5-HT4 receptor in other tissues and species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00178965
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  • 4
    Electronic Resource
    Electronic Resource
    An inhibitory prejunctional 5-HT1-like receptor in the isolated perfused rat kidney (1986)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 332 (1986), S. 8-15 
    Details
    ISSN: 1432-1912
    Keywords: Perfused rat kidney ; 5-Hydroxytryptamine ; 5-Hydroxytryptamine agonists ; 5-Hydroxytryptamine antagonists ; 5-Hydroxytryptamine receptors ; Prejunctional 5-HT1-like receptors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The present study has identified a receptor for 5-hydroxytryptamine (5-HT) which functions to inhibit the stimulus-induced release of [3H] noradrenaline following sympathetic periarterial nerve stimulation to the isolated perfused rat kidney. In addition to 5-HT (IC30=4.5×10−8 mol/l), both 5-carboxamidotryptamine (IC30=8×10−9 mol/l) and 5-methoxy-3-(1,2,3,6-tetrahydro-4-pyridinyl) indole (RU-24969, IC30=2.5×10−7 mol/l) acted as agonists whereas 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) was inactive. The inhibitory effect of 5-HT on the electrically-evoked release of tritium was antagonized in a concentration-dependent manner by methiothepin (IC50=4×10−9 mol/l), metergoline (IC50=4×10−8 mol/l) and methysergide (IC50=1.3×10−7 mol/l) but not by cyproheptadine, ketanserin, mesulergine, (−)-propranolol, (±)-pindolol, (±)-cyanopindolol, metoclopramide or phentolamine. It is concluded that the receptor to 5-HT conforms to general criteria defining 5-HT1-like receptors but at the present time the receptor site cannot be fitted to the designated 5-HT1A, 5-HT1B or 5-HT1C subtypes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00633190
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  • 5
    Electronic Resource
    Electronic Resource
    Shape coexistence and strong shape changes in very neutron deficient platinum isotopes (1990)
    Springer
    The European physical journal 337 (1990), S. 283-292 
    Details
    ISSN: 1434-601X
    Keywords: 21.60.Ev ; 29.30.Kv ; 27.70.+q
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract High spin states of175, 176Pt have been populated in144Sm(35Cl,pxn) reactions at beam energies of 175–185 MeV. In-beamγ-ray spectroscopic techniques using the ESSA30 spectrometer array were adopted. Levels up to spin 26 in176Pt and tentatively up to spin 45/2 in175Pt have been identified. The data are interpreted within the framework of Cranked Shell Model calculations using the deformed Woods-Saxon potential and including monopole pairing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01289694
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