Evidence for the presence of serotonergic perikarya in the fetal rat pancreas as demonstrated by the high affinity uptake of [³H]5-HT

Evidence has been obtained for the presence of serotonergic fibers in the adult rat pancreas; however, the location of the serotonergic cell bodies remains unknown. Fetal rat pancreata (18, 20 and 22 days) were demonstrated to possess a high-affinity uptake of serotonin. Radioautography revealed the uptake sites to be similar to those seen in the adult, indicating the presence of serotonergic fibers in early development. In addition, cell bodies, possibly representing primitive neurons, were demonstrated to be heavily labelled. This suggests a possible intra-pancreatic location for the cell bodies of the pancreatic nerves. The preservation of the specific serotonin uptake in 18-day fetal tissue after 4 days in organ culture substantiates this view.