The transient appearance of proneurotensin mRNA in the rat hypoglossal nucleus during development

Using a sensitive non-radioactive in situ hybridization technique utilizing alkaline phosphatase labelled oligodeoxynucleotide neurotensin probe we have observed the transient expression of neurotensin mRNA in the rat hypoglossal nucleus. Neurotensin mRNA containing cells were first observed on embryonic day 14 in the primodium of the hypoglossal nucleus. The intensity of the mRNA signal increased during the perinatal period until a maximum signal was observed at birth. After this time, the intensity of the neurotensin mRNA signal decreased dramatically during the first postnatal week. Subsequently the mRNA signal decreased gradually during maturation until only a very weak signal was detected in the adult. The visualization of neurotensin mRNA containing cells in the hypoglossal nucleus has not previously been reported. The transient expression of NT mRNA containing cells prior to birth may suggest that neurotensin has a role in the development of this nucleus.