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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 594 (1990), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1912
    Keywords: Key words Cardiomyocytes ; Opioid receptors ; G proteins ; Pertussis toxin ; Dynorphin ; U-50 ; 488 ; Naloxone ; Nor-binaltorphimine ; DADLE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Opioids directly decrease the contractile response of isolated ventricular cardiomyocytes to electrical stimulation. To investigate whether these effects are mediated via GTP-binding Gi/o proteins we examined the influence of pertussis toxin on the effects of the κ-opioid receptor agonist trans-(±)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)-cyclohexyl]-benzeneacetamide (U-50,488) methanesulphonate and on the as yet undescribed effects of the opioid peptide dynorphin A (1–8) on contraction. In isolated, electrically driven, rat ventricular cardiomyocytes both agents concentration dependently reduced cell shortening within 15 min, decreasing the contractile response by 79±4% (n=5) and 62±2% (n=6) of control values at maximal effective concentrations of 10 µM (U-50,488) and 1 µM [dynorphin A (1–8)], respectively. Pertussis toxin pre-treatment (200 ng/ml; 4.5–5 h) completely abolished the effects of U-50,488 and dynorphin A (1–8) on the contractile response, indicating that these effects are mediated via Gi/o proteins. In addition, the non-selective opioid receptor antagonist (–)-naloxone and the κ-opioid receptor antagonist nor-binaltorphimine antagonized the effects of U-50,488 and dynorphin A (1–8) on the contractile response. Furthermore, the µ- and δ-opioid receptor agonist (D-Ala2, D-Leu5)-enkephalin (DADLE) had no effects on contraction. These results indicate that the decrease in cell shortening is due to stimulation of κ-opioid receptors. The direct effect of κ-opioid receptor agonists on the contractile response thus represents an additional mechanism for decreasing cardiac contractility, besides the M-cholinoceptor- or adenosine receptor-mediated pathway. It is conceivable that increased release of endogenous dynorphins from the heart during hypoxia may protect the heart in a similar manner to adenosine.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The intracerebral distribution patterns of 14C-morphine, 3H-dihydromorphine, and 3H-fentanyl after intraventricular injection were studied autoradiographically in rats and rabbits. The extent of permeation into the ventricular wall was measured at different times after injection. The hydrophilic morphine and dihydromorphine could be demonstrated within the tissue up to 4 hours. They seemed to be retained within the gray matter and hindered in crossing fiber bundles. On the other hand, the lipophilic fentanyl was quickly removed from the brain but remained relatively longer demonstrable within the white matter. Also, after intrathecal injection of 14C-morphine a time dependent spread from the injection site was observed. The use of autoradiography in pharmacological experiments as described was found advantageous. Thus, it is possible to correlate directly, the time course of the pharmacological effect and the respective distribution pattern of the drug applied. This may lead to better information about the probable sites of drug action.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 331 (1985), S. 351-354 
    ISSN: 1432-1912
    Keywords: Human β-casein ; Opioid peptides ; Opioid receptor ligands ; Human β-casomorphins ; Computerized binding data analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Opioid activities of human β-casomorphin-4,-5,-7 and -8 and, for comparison, of the corresponding bovine β-casomorphins were studied in the guinea-pig ileum preparation. Binding parameters, i.e. K d -values and binding site concentrations, for the interaction of human and bovine β-casomorphins with opioid receptors in rat brain homogenates were determined in inhibition experiments, using [3H]-(d-Ala2, MePhe4, Gly-ol5)enkephalin, [3H]-(d-Ala2, d-Leu5)enkephalin and [3H]ethylketazocin as μ-, δ- and κ-opioid receptor ligands. Analysis of binding data was performed using a non-linear curve fitting program. All β-casomorphins examined displayed opioid activity. The affinity was highest for μ-receptors, less so for δ-receptors and lowest for κ-receptors. It is suggested that human β-casomorphins might play a role as “food hormones”.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 297 (1977), S. S51 
    ISSN: 1432-1912
    Keywords: Endorphins ; enkephalin ; endogenous peptides ; neurohormones ; opiates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary From brain and from pituitary tissue of vertebrates several peptides —with molecular weights between 500 and 3500 daltons — have been isolated, which behave like opiates in opiate receptor binding assays, in isolated tissue preparations and in the intact animal.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-904X
    Keywords: β-endorphin in human plasma ; multiple β-endorphin immunoreactive materials ; HPLC of peptides ; multiple radioimmunoassay system ; peptide region specific radioimmunoassays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A method for the determination of β-endorphin and β-endorphin fragments in human plasma was developed. β-Endorphin-related peptides were extracted from plasma using octadecasilyl-silica cartridges. Extracts were subjected to re versed-phase high-performance liquid chromatography (HPLC). Extracts as well as HPLC column eluates were assayed using a multiple radioimmunoassay system; several antibodies directed against various distinct regions of the β-endorphin molecule were employed. Using this method, evidence for the presence of multiple β-endorphin fragments in the plasma of healthy young volunteers (under normal conditions) was obtained.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 43 (1997), S. 99-117 
    ISSN: 0006-3525
    Keywords: milk proteins ; opioid peptides ; opioid receptor ligands ; milk opioids ; alpha-casein exorphins ; beta-casomorphins ; beta-casorphin ; casoxin A, B, C or D ; alpha-lactorphins ; beta-lactorphin ; lactoferroxins ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Milk is a mammalian characteristic and is of particular importance for humans: Mother's milk or its substitutes from cows' milk are absolutely essential nutriments for the neonate and cows' milk also represents a basic foodstuff for adults.However, in addition to their well-known nutritive role, milk constituents apparently are also able to carry specific information from the milk producer's to the milk receiver's organism: Thus, a number of milk protein fragments has been shown to behave like opioid receptor ligands able to address opioidergic systems in the adult's or in the neonate's organism.With respect to the proteins, which they are derived off, these peptides have been named α-casein exorphins or casoxin D (α-casein), β-casomorphins or β-casorphin (β-casein), casoxin or casoxin A, B, or C (κ-casein), α-lactorphins (α-lactalbumin), β-lactorphin (β-lactoglobulin) or lactoferroxins (lactoferrin). Only casoxins and lactoferroxins display antagonistic properties; the other peptides behave like opioid receptor agonists.Most of the information available so far has been collected about β-casomorphins. These peptides obviously can be released from β-casein in the adult's or in the neonate's organism, where they might elicit opioid effects in the frame of a regulatory role as “food hormones”. Several synthetic β-casomorphin derivatives have been shown to be highly specific and potent μ-type opioid receptor ligands which frequently have been used as standard tools in opioid research. © 1997 John Wiley & Sons, Inc. Biopoly 43: 99-117, 1997
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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