СHANGES IN THE ULTRASTRUCTURE OF PAIRED MAUTHNER GOLDFISH NEURONS RELATED TO VESTIBULAR AND VISUAL STIMULATION AND APPLICATION OF BETA-AMYLOID TO NEURONS
The influence of vestibular long-lasting (rotatory) and visual (optokinetic) stimulation and the application of the aggregated beta-amyloid fragment 25–35 to these neurons on the ultrastructure of goldfish Mauthner neurons was examined. A comparative study of changes in the ultrastructure of each neuron of the pair under these influences was made. By the action of beta-amyloid and stimulation, neurons showed the signs of degeneration predominantly affecting the cytoskeleton, mitochondria, and the afferent synaptic apparatus. The manifestation of the degenerative processes depended on the mode of stimulation activating a specific afferent input to the neuron and the functional state of the neuron. In the case of visual stimulation, the destruction of subcellular structures was expressed to a greater extent than after vestibular stimulation. Under the same stimulation, the signs of degeneration in the functionally dominant neuron in each pair were more pronounced than those in the other, less active neuron. It is concluded that Mauthner neurons can serve as an adequate cell model for the study of neurodegeneration and possible ways of protecting the neuron structure from damage by toxins and long-lasting stimulation.