Summary
The effect of purified Naja nigricollis phospholipase A on slices from motor cortex from rat brain was analysed at an ultrastructural level. Samples stabilized directly with glutaraldehyde were compared with samples incubated in buffer with or without enzyme.
Plasma membranes of nerve terminals, synaptic contact regions and synaptic vesicles were the main parameters studied. As judged by the electron microscopic technique the synaptic areas show a high resistance to the enzyme treatment. The intercellular space of the synaptic cleft seems unaltered. At the highest concentrations of the enzyme an increased density is noticed at the presynaptic part of the membrane. The extracellular space widens and nerve terminals and mitochondria become distended with increasing enzyme concentrations. The membranes all through the tissue appear ruptured to small pieces and at the highest enzyme concentrations used, altered in their structural organization. Quantitative analysis shows that the number of synaptic vesicles per unit surface area decreases, while ruptures of the plasma membranes of nerve terminals increase in number with increasing enzyme concentrations.
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This investigation was supported by grants No. B71-40X-3282-01 and No. B72-12X-3282-02 from the Swedish Medical Research Council.
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Cedergren, E., Johansson, B., Heilbronn, E. et al. Ultrastructural analysis of phospholipase a induced changes in membranes of synaptic regions in rat motor cortex. Exp Brain Res 16, 400–409 (1973). https://doi.org/10.1007/BF00233431
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DOI: https://doi.org/10.1007/BF00233431