[Bioelectrical activity and ultrastructure of medicinal leech Retzius neurons during chronic direct and synaptic activation].

The threshold direct or synaptic 1/sec stimulation of the Retzius cells increases the firing rate of the neuron in the leach. The firing rate becomes synchronized with the stimulation applied. The membrane potential does not change. After 10 min of such stimulation changes occurring in the ultrastructure of neuron are similar to those in a neuron with no stimulation: these changes reveal a decrease in the synthetic processes whereas the bioelectrical activity remains the same which suggests a certain independence of the neuron electrophysiological parameters of its ultrastructure.