Localization of vasoactive intestinal peptide immunoreactivity in human foetus and newborn infant spinal cord

Using an indirect immunofluorescence method the distribution of vasoactive intestinal peptide (VIP) immunoreactivity was studied in human foetus and newborn infant spinal cord and dorsal root ganglia. Further, for comparison some newborn infant brains were also investigated. Vasoactive intestinal peptide-like immunoreactive fibres were exclusively found in the caudal spinal cord and corresponding dorsal root ganglia. No immunoreactive cell bodies were detected. The first appearance of VIP-like immunoreactive fibres in both spinal cord and dorsal root ganglia was suggested during the fourth month of foetal life. Most immunolabelled fibres, concentrated in the sacral segment, were distributed in the Lissauer tract, along the dorsolateral gray border, in the intermediolateral areas and near the central canal in the dorsolateral commissure. A few VIP-like immunoreactive fibres were also seen in the dorsal funiculus and occasionally in the ventral gray horn and ventral roots. Further, a large population of VIP-like immunoreactive fibres occurs longitudinally in dorsal root, in ganglia and in the spinal nerve exit zone. These findings indicate the early appearance of VIP-like immunoreactive fibres in the human foetus spinal cord and corresponding ganglia. Moreover, they emphasize that in both foetus and newborn infant spinal cord VIP-like immunoreactive fibre distribution is limited to the lumbosacral segment.