Developmental expression of oxytocin receptors in the neonatal medulla oblongata and pons

Abstract

The distribution of oxytocin receptors (OTRs) in the postnatal brain stem of rats was examined by immunohistochemistry. Fibrous or rounded shaped OTR-immunoreactive structures were distributed densely in sensory nuclei, such as the gracile nucleus, the solitary nucleus, and the spinal trigeminal nucleus, evenly in the reticular formation of the medulla oblongata and pons, and moderately in the locus coeruleus during the neonatal period, but disappeared by postnatal day 10. Few OTR-immunoreactive structures were distributed in motor nuclei. Many rounded OTR-immunoreactive structures were discovered layered and partially overlapping with GM-130-immunoreacivity in the neuronal Golgi apparatus, which was confirmed by electron microscopy. The present study suggests that a transient type of OTR may be functioning in neuronal development during the neonatal period.