[Ultrastructural changes in the perimembranous layer of the ganglionic neurons during orthodromic pessimal stimulation].

By means of the transmissive electron microscope certain changes in ultrastructure of the perimembranous layer in the frog ganglionar neurons have been studied. They occur at an orthodromic synaptic stimulation (40 Hz for 10 and 20 min, 100 Hz for 20 min). Formation of a number of heterogenous membranes according to their electron density and thickness of submembranous aggregates is noted: sharply manifested sub-membranous thickenings, resembling postsynaptic thickenings of the synapse, thick membranes, differing from more thin membranes of glyocytes and making an image of asymmetry in the adjoining membranes. In their area a massive formation of coated vesicles, local desmosome-like junctions are noted. A reactive rearrangement of submembranous cisterns and other organelles associated with the membrane is demonstrated. The ultrastructural changes mentioned are evidently important for generation of the action potential under conditions of the pessimal stimulation.