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Metal ion content of cholinergic synaptic vesicles isolated from the electric organ of Torpedo: Effect of stimulation-induced transmitter release
| Content Provider | Semantic Scholar |
|---|---|
| Author | Schmidt, René Zimmermann, Herbert Whittaker, Victor P. |
| Copyright Year | 1980 |
| Abstract | Abstract Cholinergic synaptic vesicles were isolated from the Torpedo electric organ by a combination of differential and density gradient centrifugation. Iso-osmolar solutions of glycine or NaCl were used as homogenization and preparation media. The metal content of intact tissue and subcellular fractions were determined by atomic absorption spectroscopy. In the synaptic vesicle fraction ratios of metals to acetylcholine (g atom/mol) were: Na, 0.30; K, 0.10; Mg, 0.07; Ca, 0.28. Filtration of isolated vesicles revealed that the strength of metal binding depends on the ionic potential of the metal cation. Thus alkali metal ions are bound to synaptic vesicles less tightly than alkaline earth metals. Incubation of vesicles with elevated levels of NaCl led to a partial exchange of Na with K but external concentrations of CaCl 2 in the physiological range were without effect on vesicle metal ion content. Stimulation of the electric organ in vivo (5000 impulses, 5 Hz) caused a depletion of the acetylcholine and adenosine 5′-triphsophate content of the vesicles whereas the levels of metal ions were increased. It is suggested that the release of acetylcholine from synaptic vesicles exposes free negative charges to which extracellular metal cations can bind in ion exchange. |
| Starting Page | 625 |
| Ending Page | 638 |
| Page Count | 14 |
| File Format | PDF HTM / HTML |
| DOI | 10.1016/0306-4522(80)90060-3 |
| Alternate Webpage(s) | https://api.elsevier.com/content/article/pii/0306452280900603 |
| Alternate Webpage(s) | https://www.sciencedirect.com/science/article/pii/0306452280900603?dgcid=api_sd_search-api-endpoint |
| PubMed reference number | 7374962 |
| Alternate Webpage(s) | https://doi.org/10.1016/0306-4522%2880%2990060-3 |
| Journal | Medline |
| Volume Number | 5 |
| Journal | Neuroscience |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
