Endomorphin 1 and 2, the endogenous μ-opioid agonists, produce biphasic changes in systemic arterial pressure in the cat

Hunter C. Champion, Trinity J. Bivalacqua, David G. Lambert, Sean M. McWilliams, James E. Zadina, Abba J. Kastin, Philip J. Kadowitz

Research output: Contribution to journalArticlepeer-review

Abstract

The endogenous peptides endomorphin I and 2 are newly isolated, potent, selective μopioid receptor agonists. In the present study, responses to the endomorphin peptides were investigated in the systemic vascular bed of the cat, Endomorphin 1 and 2 induced dose-related biphasic changes in systemic arterial pressure when injected in doses of 1-30 nmol/kg i.v. The biphasic responses to endomorphin 1 and 2 were characterized by an initial increase followed by a decrease in systemic arterial pressure. In terms of relative vasodepressor activity, endomorphin 1 and 2 were similar in potency and approximately 10-fold less potent than the ORL, ligand nociceptin (orphanin FQ) in decreasing systemic arterial pressure. The biphasic arterial pressure changes in response to endomorphin 1 and 2 were inhibited by the opioid receptor antagonist naloxone in a dose of 2 mg/kg i.v. These results demonstrate that endomorphin 1 and 2 produce significant, naloxone-sensitive changes in systemic arterial pressure that are characterized by an initial increase followed by a secondary decrease in arterial pressure in the cat.

Original languageEnglish (US)
Pages (from-to)PL131-PL136
JournalLife Sciences
Volume63
Issue number9
DOIs
StatePublished - Aug 24 1998
Externally publishedYes

Keywords

  • Endomorphin
  • Oploid peptides
  • Systemic vascular bed
  • Vasodepressor response
  • Vasopressor response

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

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