Simulation of action potential propagation in terminal arborizations of cultured sensory ganglia.

In order to study possible integrative properties of axon terminations, impulse propagation in arbitrarily complex terminal arborizations is simulated using a general purpose network analysis program. Detailed, anatomically based models are constructed from HRP-filled arborizations of sensory ganglia impinging upon motoneurons grown in an organotypic rat spinal cord culture. On assuming an excitable membrane the action potential propagates into all the ramifications. If some branches are assumed to be inexcitable, the electrotonically propagated potential may not depolarize the synaptic endings sufficiently to release transmitter. Under such conditions only part of the morphologically found synapses are expected to release transmitter following stimulation of sensory neurons.