The intracellular distribution of horseradish peroxidase (HRP) transported intra-axonally from the mesenteric nerve to the wall of the small intestine has been examined electron microscopically. After 2 days, some of the neurons of the myenteric and submucosal plexuses showed an accumulation of HRP. The HRP reaction product consisted of fine, discrete cytoplasmic granules and it was located in lysosome-like dense bodies with a 400-500 nm of diameter. The morphological features of the labelled neurons, with synapses occurring on their surfaces, were apparently different from those of unlabelled neurons. Some nerve fibers were also labelled and could be found in all layers of the small intestine. The labelled neurons project directly towards the celiac ganglia, and due to the synapses on their surfaces, it is supposed that these neurons collect information from other local nerve cells and centripetally convey them to the prevertebral ganglia.