James J. Liu, Paddy A. Phillips, Louise M. Burrell, Brian B. Buxton, Colin I. Johnston

Research output: Contribution to journalConference articlepeer-review

13 Citations (Scopus)


1. OPC‐21268 and OPC‐31260 are newly developed orally active non‐peptide vasopressin (AVP) V1 and V2 receptor antagonists, respectively. The effects of the two compounds on human vessels have not been studied. 2. The effects of the two compounds on AVP‐induced contraction of human internal mammary arteries (IMA) were investigated. Their effects were compared with the peptide V1 and V2 antagonists d(CH2)sSar7AVP (SAVP) and d(CH2)5D‐Ileu211eu4AVP (Ileu2 Ileu4AVP), respectively. 3. The V1 antagonist OPC‐21268 failed to antagonize AVP‐induced contraction at low concentrations and potentiated the contraction at higher concentration (3 × 107 mol/L, P<0.05). It also caused a mild direct contractile effect on IMA. In contrast, the peptide V1 antagonist SAVP potently inhibited the AVP‐induced contraction, indicating that functionally constrictor V1 receptors exist in IMA. Both the nonpeptide and peptide V2 antagonists OPC‐31260 (3X106 mol/L) and Ileu2Ileu4AVP significantly antagonized the AVP‐induced contraction (P<0.01). 4. The AVP‐induced contraction was reversed by high concentrations of OPC‐31260 (106 mol/L‐3×105 mol/L) but not by OPC‐21268 (up to 3X 105 mol/L). 5. These studies indicate that, in human IMA, OPC‐21268 is a partial VI receptor agonist with no V1 receptor antagonist activity, while OPC‐31260 is a V1 receptor antagonist. The results also indicate that Ileu2 Ileu4AVP may be a Vl receptor antagonist in humans.

Original languageEnglish
Pages (from-to)121-124
Number of pages4
JournalClinical and Experimental Pharmacology and Physiology
Issue number2
Publication statusPublished - Feb 1994
Externally publishedYes


  • human internal mammary artery
  • non‐peptide vasopressin antagonists
  • peptide vasopressin antagonists.


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