Somal size and location within the ganglia for electrophysiologically identified myenteric neurons of the XXXX ileum.

@entity3798 @entity840
The main goal of the present study was to examine the possibility of electrophysiologically identifying the excitable enteric S and @entity3798 neurons by use of one single criterion. Intracellular recordings were made from 189 cells of 64 ganglia in isolated preparations of the myenteric plexus of the @entity840 distal ileum. The recordings were made under visual control of the cells by using Hoffman Modulation Contrast optics at high magnification (600x). From photomicrographs, the soma size and the location within the ganglion of the individual (unstained) cells were determined. The cells were classified into three types according to their electrical excitability and the shape of the action potential. Excitable cells were classified as @entity3798 cells (n = 84) if the action potential showed a shoulder on the falling phase, otherwise as S cells (n = 56). Cells in which no action potential could be evoked by current injection were classified as nonspiking (NS) cells (n = 49). The three classes of cells showed significant differences with respect to membrane potential, input resistance and fast synaptic input. The @entity3798 cells had significantly larger somata (P < 0.01) than the S cells. The NS cells were significantly smaller than the @entity3798 and S cells (P < 0.01). @entity3798 and S cells were found to be randomly located in the ganglia, whereas the NS cells clustered (P < 0.008) in close proximity to the onsets of internodal strands. We conclude that the shoulder of the action potential can be used as a single criterion to distinguish "on line" S and @entity3798 neurons unequivocally.
