Endomorphin-1 and endomorphin-2: Pharmacology of the selective endogenous μ-opioid receptor agonists

Research output: Contribution to journalReview article

108 Citations (Scopus)


The recently discovered endogenous opioid peptides, endomorphins-1 and -2, appear to have properties consistent with neurotransmitter/neuromodulator actions in mammals. This review surveys the information gained so far from studies of different aspects of the endomorphins. Thus, the endomorphins have been found unequally in the brain; they are stored in neurons and axon terminals, with a heterogeneous distribution; they are released from synaptosomes by depolarization; they are enzymatically converted by endopeptidases; and they interact specifically and with high affinity with μ-opioid receptors. The most outstanding effect of the endomorphins is their antinociceptive action. This depends on both central and peripheral neurons. Additionally, the endomorphins cause vasodilatation by stimulating nitric oxide release from the endothelium. Their roles in different central and peripheral functions, however, have not been fully clarified yet. From a therapeutic perspective, therefore, they may be conceived at present as potent antinociceptive and vasodilator agents.

Original languageEnglish
Pages (from-to)437-463
Number of pages27
JournalPharmacology and Therapeutics
Issue number3
Publication statusPublished - Dec 1 2000



  • Antinociception
  • Cardiovascular
  • Endogenous peptide
  • Endomorphin-1
  • Endomorphin-2
  • μ-Opioid receptor

ASJC Scopus subject areas

  • Pharmacology
  • Pharmacology (medical)

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