Caffeine inhibits Ca2+ uptake by subplasmalemmal calcium stores (‘alveolar sacs’) isolated from Paramecium cells
| Autor: | Helmut Plattner, Johannes-Dieter Wissmann, Siegfried Länge |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
SERCA
sarcoplasmic endoplasmic reticulum Ca2+-ATPase Paramecium (Paramecium) Biophysics chemistry.chemical_element ATP adenosine trisphosphate Calcium Biochemistry Exocytosis Lactones chemistry.chemical_compound Adenosine Triphosphate CICR Ca2+-induced Ca2+-release ATPase Ca2+ In vivo Caffeine SERCA Animals Calcimycin Secretion Ca2 uptake TG thapsigargicin Ciliated protozoan biology Plant Extracts Chemistry Calcium Radioisotopes Endoplasmic reticulum Calcium store SR sarcoplasmic reticulum Cell Biology [Ca2+]i intracellular free Ca2+ concentration biology.organism_classification Calcium ion uptake InsP3 inositol 1 4 5-trisphosphate Kinetics Paramecium tetraurelia Sesquiterpenes |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Biomembranes. 1278:191-196 |
| ISSN: | 0005-2736 |
| DOI: | 10.1016/0005-2736(95)00230-8 |
| Popis: | Caffeine inhibits 45 Ca 2+ sequestration by subplasmalemmal calcium stores (‘alveolar sacs’) of low thapsigargicin sensitivity which we have isolated from the ciliated protozoan, Paramecium tetraurelia . Inhibition depends on caffeine concentration, with an IC 50 of 31.8 mM. According to kinetic evaluation this is compatible with non-competitive inhibition of Ca 2+ uptake, rather than with superimposed 45 Ca 2+ release during sequestration. It remains to be analysed whether this mechanism might be of possible relevance also for Ca 2+ -mediated activation in vivo in this or in any other secretory system. Such an effect could also operate indirectly, e.g., by Ca 2+ -release induction via sequestration inhibition. This is the first description of caffeine-mediated inhibition of Ca 2+ uptake by calcium stores from a secretory system. Our data are compatible with some observations with sarcoplasmic reticulum from striated muscle fibers. |
| Databáze: | OpenAIRE |
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