Demonstration of negative tissue charges by means of polyethyleneimine-metal complexes.

Three polyethyleneimine-metal complexes were synthesized and cytochemically tested for demonstration of negatively charged sites. For this purpose rat cerebral cortex synaptosomes were used. It was established that both types of polyethyleneimine-copper complexes labeled the synaptosomal membrane and synaptic vesicles with electron-dense granules, whereas the polyethyleneimine-lead complex marked the anionic sites with amorphous electron-dense material.