Cells expressing preproenkephalin mRNA in the rat pineal gland are not serotonin-producing pinealocytes: Evidence using in situ hybridization combined with immunocytochemistry for serotonin

Xi Tao Wang, George D. Pappas, Jacqueline Sagen, James R. Unnerstall

Research output: Contribution to journalArticle

4 Scopus citations


1. Preproenkephalin (PPEnk) mRNA expressing cells have been identified in rat pineal gland using radioactive in situ hybridization histochemistry. 2. Approximately 7% of the cells in the pineal gland (7.5 ± 0.86, mean ± 95% CI) express PPEnk mRNA. These cells are distributed throughout the pineal as either scattered single cells or small groups of cells with large round or oval nuclei. 3. Using in situ hybridization combined with ABC immunocytochemistry for serotonin (5-HT) in the same pineal sections, the PPEnk mRNA labeling cells are found not to be serotonin-immunoreactive cells. These data indicate that the PPEnk mRNA is expressed in a certain discrete subpopulation of cells in the rat pineal gland and these cells are not serotonin-producing pinealocytes. 4. The physiologic role of PPEnk-derived peptides in the pineal remains unknown. It is possible that these peptides either are synthesized and secreted as hormones or act as pineal paracrine signals.

Original languageEnglish
Pages (from-to)73-84
Number of pages12
JournalCellular and Molecular Neurobiology
Issue number1
StatePublished - Feb 23 1996
Externally publishedYes



  • double labeling
  • immunocytochemistry
  • in situ hybridization
  • pineal
  • preproenkephalin mRNA
  • serotonin

ASJC Scopus subject areas

  • Neuroscience(all)
  • Clinical Biochemistry
  • Cell Biology
  • Genetics

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