ABSTRACT
The extrinsic innervation of the rabbit distal colon was studied by the use of the horseradish peroxidase (HRP) tracing technique. After injection of HRP, labelled cells were observed in sacral spinal cord segments S2-S5, primarily in the lateral intermediate grey matter. Labelled neurons were also observed in the lateral funiculus and sometimes in the ventral horn. No labelled cells were found in the vagal nuclei, contrary to the reports of earlier investigators. Anterograde transport of HRP resulted in labelling of visceral afferent neurons in dorsal root ganglia, whilst the central processes of afferent neurons entered Lissauer's tract and formed a collateral pathway along the lateral edge of the dorsal horn which terminated in close apposition to labelled preganglionic efferent neurons.
