[Strength of synaptic stimulation and morpho-functional reorganization of the neuron]

In the Retzius cell of the leech, synaptic threshold and three-fold threshold stimulation 1/sec was followed by readjustment of the cell spike activity according to the stimulation rhythm. After cessation of the stimulation the initial bioelectrical activity restores. The membrane potential remains unaltered during the three-fold threshold stimulation. Electron-microscopically, the Retzius cells develop different ultrastructural changes. In case of the threshold stimulationthe changes indicate an intensification of the synthetic processes and, on the contrary, the three-fold threshold stimulation is followed by a decrease in the proteinmetabolism. In the first case, the amount of granular endoplasmatic reticulum increases and in the second case -- decreases. The same is true for the total amount of ribosomes. During synaptic stimulation, the Retzius cell mitochondria remain unlatered while during the three-fold threshold stimulation the mitochondria swell, their matrix clears up, and their krysts become reduced.