Search Results - (Author, Cooperation:D. A. Eberhard)

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  1. 1
    Staff View
    Publication Date:
    2013-10-18
    Publisher:
    Nature Publishing Group (NPG)
    Print ISSN:
    0028-0836
    Electronic ISSN:
    1476-4687
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Natural Sciences in General
    Physics
    Keywords:
    Checklist ; Clinical Trials as Topic/economics/ethics/*methods/standards ; Evaluation Studies as Topic ; *Genomics/ethics ; Humans ; Models, Biological ; National Cancer Institute (U.S.)/economics ; Precision Medicine/ethics/methods/standards ; *Research Design/standards ; Specimen Handling ; United States
    Published by:
    Latest Papers from Table of Contents or Articles in Press
  2. 2
    Eberhard, D. A. ; Holz, R. W.

    Oxford, UK : Blackwell Publishing Ltd
    Published 1987
    Staff View
    ISSN:
    1471-4159
    Source:
    Blackwell Publishing Journal Backfiles 1879-2005
    Topics:
    Medicine
    Notes:
    Abstract: The ability of cholinergic agonists to activate phospholipase C in bovine adrenal chromaffin cells was examined by assaying the production of inositol phosphates in cells prelabeled with [3H]inositol. We found that both nicotinic and muscarinic agonists increased the accumulation of [3H]inositol phosphates (mainly inositol monophos-phate) and that the effects mediated by the two types of receptors were independent of each other. The production of inositol phosphates by nicotinic stimulation required extracellular Ca2+ and was maximal at 0.2 mMCa2+. Increasing extracellular Ca2+ from 0.22 to 2.2 mM increased the sensitivity of inositol phosphates formation to stimulation by submaximal concentrations of 1,1-dimethyl-4-phenyl-piperazinium iodide (DMPP) but did not enhance the response to muscarine. Elevated K+ also stimulated Ca2+-dependent [3H]inositol phosphate production, presumably by a non-receptor-mediated mechanism. The Ca2+ channel antagonists D600 and nifedipine inhibited the effects of DMPP and elevated K+ to a greater extent than that of muscarine. Ca2+ (0.3–10 μM) directly stimulated the release of inositol phosphates from digitonin-permeabilized cells that had been prelabeled with [3H]inositol. Thus, cholinergic stimulation of bovine adrenal chromaffin cells results in the activation of phospholipase C by distinct muscarinic and nicotinic mechanisms. Nicotinic receptor stimulation and elevated K+ probably increased the accumulation of inositol phosphates through Ca2+ influx and a rise in cytosolic Ca2+. Because Ba2+ caused catechol-amine secretion but did not enhance the formation of inositol phosphates, phospholipase C activation is not required for exocytosis. However, diglyceride and wyo-inositol 1,4,5-trisphosphate produced during cholinergic stimulation of chromaffin cells may modulate secretion and other cellular processes by activating protein kinase C and/or releasing Ca2+ from intracellular stores.
    Type of Medium:
    Electronic Resource
    URL:
    Articles: DFG German National Licenses