Journal article
Effect of maitotoxin on cytosolic Ca 2+ levels and membrane potential in purified rat brain synaptosomes
Biochimica et biophysica acta. Biomembranes, v 1026(1), pp 126-132
1990
PMID: 2378876
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
In this study, the effects of the marine toxin maitotoxin on cytosolic Ca
2+ levels and membrane potential in rat brain synaptosomes were evaluated. Maitotoxin (10 ng/ml) caused a remarkable increase of intrasynaptosomal Ca
2+ levels monitored by the fluorescent probe fura-2. This increase was prevented by the removal of external Ca
2+ ions. Tetrodotoxin, as well as the removal of extracellular Na
+ ions, failed to affect maitotoxin-induced increase of intrasynaptosomal Ca
2+ levels. Also the complete removal of all monovalent and divalent cations, except Ca
2+ ions, from the incubation medium (0.32 M sucrose substitution), was unable to prevent the effect of maitotoxin on intrasynaptosomal Ca
2+ levels. Maitotoxin (0.3–10 ng/ml), produced a dose-dependent depolarization of synaptosomal membranes, which required the presence of extracellular Ca
2+ ions. The substitution of extracellular Na
+ with choline or the removal of all cations from the incubation medium and their replacement with an isotonic concentration of sucrose (0.32 M), did not prevent the depolarizing effect exerted by maitotoxin. Also under these two ionic conditions, the effect of maitotoxin on membrane potential was critically dependent on the presence of 1 mM extracellular Ca
2+. The depolarizing effect exerted by maitotoxin on synaptosomal membrane potential was also observed when extracellular Ca
2+ ions were substituted with an equimolar concentration of Ba
2+ or Sr
2+ ions. In summary, these results appear to suggest that, in presence of 1 mM extracellular Ca
2+ ions, maitotoxin depolarizes synaptosomal plasmamembrane by promoting the influx of extracellular Ca
2+ ions. This enhanced influx of Ca
2+ causes an increase of intrasynaptosomal Ca
2+ levels.
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Details
- Title
- Effect of maitotoxin on cytosolic Ca 2+ levels and membrane potential in purified rat brain synaptosomes
- Creators
- Maurizio Taglialatela - University of Naples Federico IILorella M.T. Canzoniero - University of Naples Federico IIAlessandro Fatatis - University of Naples Federico IIGianfranco Di Renzo - University of Naples Federico IITakeshi Yasumoto - Tohoku UniversityLucio Annunziato - University of Chieti-Pescara
- Publication Details
- Biochimica et biophysica acta. Biomembranes, v 1026(1), pp 126-132
- Publisher
- Elsevier
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- College of Medicine; Pharmacology and Physiology; Drexel University
- Web of Science ID
- WOS:A1990DT10200018
- Scopus ID
- 2-s2.0-0025351764
- Other Identifier
- 991020100193804721
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- Collaboration types
- Domestic collaboration
- International collaboration
- Web of Science research areas
- Biochemistry & Molecular Biology
- Biophysics