THE SUBCELLULAR DISTRIBUTION OF PARTICLE-BOUND NEGATIVE CHARGES IN RAT BRAIN

Abstract— Ferritin cationized with Girard's reagent T [(CH₃)₃NCH₂CONHNH₂] was used as a marker for negative electric charges on subcellular components of rat brain. Pre- and postsynaptic membranes did not bind cationic ferritin, either on their outer or their inner surface. Vesicular membranes, however, were heavily labelled with cationic ferritin. Post- and presynaptic densities appeared to carry a large number of negative charges. Cationic ferritin was also bound within the synaptic cleft. The density varied, however, from synapse to synapse: in general, binding within the cleft was significantly reduced when the synaptosomes were pretreated with 1 M-NaCl. Cationic ferritin was observed in high density on the outer surface of myelin sheaths and even between the lamellae at the intraperiod lines. Neuro-tubules and neurofilaments bound cationic ferritin in significant amounts. The results are discussed in relation to the mechanism of neurotransmission and to the binding and transport of drugs.