Neural coordination of excitation of ferret trachealis muscle.

The distribution of junction potentials and synaptic potentials to muscle cells and ganglion cells in the ferret trachealis muscle-nerve plexus preparation was studied with local electrical stimulation of branches of the laryngeal nerve or the interganglionic nerve trunk. Stimulations evoked excitatory junction potentials in muscle cells and fast excitatory postsynaptic potentials in ganglion (AH) cells located throughout the preparation, regardless of the location of the stimulating electrode. Evoked excitatory junction potentials were nearly simultaneous in widely separated muscle cells, suggesting that excitation of different muscle cells is coordinated. The apparent conduction velocity to muscle cells after a local nerve stimulation was 0.1-0.2 m/s. Dissemination of input to ganglion cells and muscle cells was dependent on the integrity of the interganglionic nerve trunk. There was evidence based on analysis of conduction velocities that coupling of electrical activity in different AH ganglion cells and muscle cells was related to the following: 1) an interlacing arrangement of myelinated preganglionic neurons that enter the plexus from multiple branches of the laryngeal nerve, and 2) interlacing neural circuits characterized by synapses between neurons whose cell bodies lie in different ganglia.