Summary
Pinched-off nerve terminals (synaptosomes) from rat cerebral cortex were depolarized with 60 mM KCl and treated with 20 mM 4-aminopyridine in order to evaluate ultrastructural alterations. The empty presynaptic terminals were counted and their number was given as a percentage of the normal terminals. The proportion of empty terminals increased from 10.47±1.56% to 32.45±1.88% (P < 0.001) following treatment with 20 mM 4-aminopyridine. This effect of 4-aminopyridine depended on the presence of Ca++ in the incubation medium. The results are discussed in terms of facilitation by 4-aminopyridine of exocytotic transmitter release. We think that the increase of the empty synaptosomes was due to the exhaustion or inhibition of the synaptic vesicle recycling mechanism.
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The work was supported by the Hungarian Ministry of Health (Grant No. 05/4-01/449) and the Hungarian Academy of Sciences (Grant No. 375/82/3.2)
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Mihály, A., Ágoston, D. 4-Ammopyridine-induced ultrastructural alterations of pinched-off nerve terminals from rat cerebral cortex. Exp Brain Res 54, 385–389 (1984). https://doi.org/10.1007/BF00236242
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DOI: https://doi.org/10.1007/BF00236242