Properties and functions of human placental opioid system

Mahmoud S. Ahmed, Bojana Cemerikic, Abdulbaki Agbas

Research output: Contribution to journalShort surveypeer-review

26 Scopus citations


Human placental villus tissue contains opioid receptors and peptides. Kappa opioid receptors (the only type present in this tissue) were purified with retention of their binding properties. The purified kappa receptor is a glycoprotein with an apparent molecular weight of 63,000. Two opioid receptor mediated functions were identified in trophoblast tissue, namely regulation of acetylcholine and hormonal (human chorionic gonadotrophin and human placental lactogen) release. Placental content of kappa receptors increases with gestational age. Term placental content of kappa receptors correlates with route of delivery (higher in those abdominally obtained). Opioid use and/or abuse during pregnancy affects placental receptor content at delivery, as well as its mediated functions. Opioid peptides identified in placental receptor content at delivery, methionine enkephalin, leucine enkephalin and dynorphins 1-8 and 1-13. Dynorphin 1-8 seem to be the predominant opioid peptide present in placental villus tissue.

Original languageEnglish (US)
Pages (from-to)83-97
Number of pages15
JournalLife Sciences
Issue number2
StatePublished - 1992
Externally publishedYes

ASJC Scopus subject areas

  • General Pharmacology, Toxicology and Pharmaceutics
  • General Biochemistry, Genetics and Molecular Biology


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