Slow intracellular potentials in AH-neurons of the myenteric plexus evoked by repetitive activation of synaptic inputs.

In after-hyperpolarization-neurons of guinea-pig myenteric plexus, several types of slow responses to repetitive activation of synaptic inputs were recorded. There were at least two types of slow excitatory depolarizing potential, both associated with an increased input resistance, but in one there was an abolition or marked attenuation of the amplitude of the slow after-hyperpolarization of the neuron, whereas in the other type the slow after-hyperpolarization was not significantly affected. Slow depolarizing and hyperpolarizing synaptic potentials associated with a decrease input resistance were also recorded in some neurons following transmural stimulation. The neural processes responsible for these slow potentials in after-hyperpolarization-neurons showed no preferential projection within the myenteric plexus.