title: Expression of orexin A and its receptor 1 in the rat epididymis.
abstract: The hypothalamic peptide orexin A (oxA) derives from the proteolytic cleavage of the precursor molecule prepro-orexin. It binds with the high affinity G-protein-coupled orexin receptor 1 (OX1R). Here, we report the detection of oxA and OX1R in the principal cells of the rat caudal epididymis by immunohistochemistry. Both oxA and OX1R immunolabelling showed cytoplasmic supranuclear localization, filling the apical portion of the cells. The expression of prepro-orexin and OX1R mRNA transcripts in the rat epididymis was assessed by reverse-transcriptase polymerase chain reaction, while the presence of both these proteins in the tissue was confirmed by Western blotting analysis. Our findings provide the evidence for the presence of oxA and OX1R in the rat epididymis, and demonstrate that both proteins are locally synthesised, thus suggesting a role for oxA in governing the fertilizing capability of the immature male gamete.
authors.affiliation: Department of Biological Structures, Functions and Technologies, University of Naples Federico II, Via F. Delpino 1, 80137 Naples, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Tafuri
authors.forename: Luigi M
authors.initials: LM
authors.lastname: Pavone
authors.forename: Roberta
authors.initials: R
authors.lastname: Lo Muto
authors.forename: Matilde
authors.initials: M
authors.lastname: Basile
authors.forename: Emilia
authors.initials: E
authors.lastname: Langella
authors.forename: Enrica
authors.initials: E
authors.lastname: Fiorillo
authors.forename: Luigi
authors.initials: L
authors.lastname: Avallone
authors.forename: Norma
authors.initials: N
authors.lastname: Staiano
authors.forename: Alfredo
authors.initials: A
authors.lastname: Vittoria