Ba2+ does not support synaptic vesicle retrieval in rat cerebrocortical synaptosomes.
To investigate whether any specific requirement for extracellular Ca2+ exists in the control synaptic vesicle retrieval, we examined the ability of the divalent cation Ba2+ to substitute for Ca2+ in both vesicle exocytosis and endocytosis. Ba2+ stimulated glutamate release from rat cerebrocortical synaptosomes. Ba2+-evoked release was inhibited by bafilomycin A1, indicating release was via exocytosis of synaptic vesicles. However, Ba2+ did not stimulate vesicle retrieval, monitored by a FM2-10-based retrieval assay. Therefore synaptic vesicle retrieval in central nerve terminals has a specific requirement for extracellular Ca2+ and the Ca2+ receptor for retrieval has a different cation specificity to the Ca2+ receptor for exocytosis.
Cousin
M A
MA
Children's Medical Research Institute, Wentworthville, NSW, Australia. mcousin@cmri.usyd.edu.au
Robinson
P J
PJ
D015761:4-Aminopyridine / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001464:Barium / Q000494:pharmacology*; D002413:Cations, Divalent / Q000494:pharmacology; D002540:Cerebral Cortex / Q000502:physiology*; D004705:Endocytosis / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005089:Exocytosis / Q000187:drug effects; D005456:Fluorescent Dyes; D018698:Glutamic Acid / Q000378:metabolism; D018942:Macrolides; D011189:Potassium Chloride / Q000494:pharmacology; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D051381:Rats; D017207:Rats, Sprague-Dawley; D013572:Synaptic Vesicles / Q000187:drug effects / Q000502:physiology*; D013574:Synaptosomes / Q000187:drug effects / Q000502:physiology*
D000900:Anti-Bacterial Agents; D002413:Cations, Divalent; D004791:Enzyme Inhibitors; C086686:FM2 10; D005456:Fluorescent Dyes; D018942:Macrolides; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D001464:Barium; D018698:Glutamic Acid; D011189:Potassium Chloride; C040929:bafilomycin A1; D015761:4-Aminopyridine; D006180:Proton-Translocating ATPases