Rapid swelling of neurons during synaptic transmission in the bullfrog sympathetic ganglion.

Neurons in the lumbar sympathetic ganglion of the bullfrog were found to respond to presynaptic stimulation with rapid mechanical changes. These changes represent swelling of the presynaptic nerve terminals, followed by swelling of the somas of the postsynaptic neurons. After complete blockade of impulse transmission with D-tubocurarine, swelling of the neurons associated with the excitatory postsynaptic potential is observed.