Transglutaminase-synthesized spermine derivative of substance P recognizes rat portal vein neurokinin-3 receptors

Life Sci. 1997;60(6):403-11. doi: 10.1016/s0024-3205(96)00665-0.

Abstract

The effects of the transglutaminase-synthesized polyamine derivatives of Substance P (SP) have been further characterized by their ability to contract in vitro the rat portal vein strip (RPV), a pharmacological preparation particularly rich in NK-3 receptors. The effects of selective agonists of NK-1, NK-2 and NK-3 receptors [Sar9,Met(O(2))11]SP, beta-Ala8 NKA(4-10), and senktide respectively, were also evaluated by measuring RPV concentration-response curves. Peptide [GR-82334 (NK-1) and MEN-10,376 (NK-2)] and nonpeptide [WIN 51,708 (NK-1) and SR 142801 (NK-3)] NK receptor antagonists were used to confirm the participation of the different NK receptors to contractile response. Our results demonstrated that the spermine derivative of SP (Spm-SP), previously shown to be unable to recognize NK-1 and NK-2 receptors in some bioassays, contracts RPV (EC50 = 588 nM) better than the native neuropeptide (EC50 = 1120 nM). A pretreatment with thiorphan, an inhibitor of neutral endopeptidases, significantly reduced such a difference. While this inhibitor shifts the SP concentration-response curves to the left (EC50 = 720 nM) the action of Spm-SP and [Sar9,Met(O(2))11]SP were completely thiorphan-resistant. In the absence of thiorphan we found the following rank order of potency: senktide > > beta-Ala8 NKA(4-10) > [Sar9,Met(O(2))11]SP = Spm-SP > SP. Among the mentioned NK receptor antagonists, only the selective NK-3 receptor antagonist, SR 142801, shifted to the right Spm-SP and [Sar9,Met(O(2))11]SP concentration-response curve, showing pKB values of 5.84 and 5.88, respectively. Therefore, the reported results suggest that the introduction of a Spm moiety into the SP alters the parent peptide molecule by increasing its affinity for NK-3 receptors and/or by preventing its degradation by some proteolytic enzymes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Androstanes / pharmacology
  • Animals
  • Benzimidazoles / pharmacology
  • In Vitro Techniques
  • Male
  • Neurokinin A / analogs & derivatives
  • Neurokinin A / pharmacology
  • Peptide Fragments / pharmacology
  • Physalaemin / analogs & derivatives
  • Physalaemin / pharmacology
  • Piperidines / pharmacology
  • Portal Vein / drug effects
  • Portal Vein / metabolism*
  • Rats
  • Rats, Wistar
  • Receptors, Neurokinin-3 / antagonists & inhibitors
  • Receptors, Neurokinin-3 / metabolism*
  • Substance P / analogs & derivatives*
  • Substance P / metabolism
  • Substance P / pharmacology
  • Thiorphan / pharmacology
  • Transglutaminases / metabolism
  • Vasoconstriction / drug effects

Substances

  • Androstanes
  • Benzimidazoles
  • Peptide Fragments
  • Piperidines
  • Receptors, Neurokinin-3
  • WIN 51708
  • senktide
  • GR 82334
  • neurokinin A(4-10), Tyr(5)-Trp(6,8,9)-Lys(10)-
  • substance P, N-spermine-Gln(5)-
  • Physalaemin
  • Substance P
  • Neurokinin A
  • Thiorphan
  • Transglutaminases
  • SR 142801