A new method of fixation of native synaptosomes and synaptosomal membranes from rat striatum was applied for their visualization by atomic-force microscopy. A scheme for examination of the surface of biological material was developed, which helps to distinguish intact synaptosomes from washed synaptic membranes and evaluate damage to synaptic membrane surface caused by ethanol (25 mM) and acetaldehyde (50 microM). The proposed method can be used for evaluation of the damaging effects of ethanol and acetaldehyde on neurons.