Structure-activity studies of neurokinin A

Neuropeptides. 1989 May-Jun;13(4):263-70. doi: 10.1016/0143-4179(89)90080-2.


A structure-activity study on neurokinin A and its C-terminal fragment NKA (4-10) has been performed in order to find selective agonists for the NK-2 receptor and identify chemical modifications suitable for protecting the peptides from degradation, while maintaining activity. Five series of compounds have been prepared and tested: 1. the complete series of the L-Ala monosubstituted analogues of NKA; 2. a series of NKA fragments from the C- or N-terminal; 3. the complete series of NKA (4-10) analogues monosubstituted with beta-Ala; 4. a series of NKA (4-10) analogues with monosubstitutions in pos. 4, 8, 10 or multisubstitutions in two or more of the same positions; and 5. a series of 6 NKA (4-10) analogues monosubstituted with 1-amino,1-cyclohexane carboxylic acid residue. It has been found that the most selective agonists for the NK-2 receptor system are [beta Ala8]NKA (4-10) and [Nle10]NKA (4-10). Protection from aminopeptidase may be obtained by acetylation of the N-terminal amide of NKA (4-10), while partial protection from endopeptidases should be expected from the presence of beta-Ala in position 8. Conformational constraints induced with 1,amino,1-cyclohexane carboxylic acid residue gave weakly active compounds. Multiple substitutions reduce rather than potentiating the favorable effects of the corresponding monosubstituted compounds.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cricetinae
  • Dogs
  • Dose-Response Relationship, Drug
  • Guinea Pigs
  • In Vitro Techniques
  • Muscle Contraction / drug effects*
  • Muscle, Smooth / drug effects
  • Muscle, Smooth, Vascular / drug effects
  • Neurokinin A / analogs & derivatives
  • Neurokinin A / pharmacology*
  • Peptide Fragments / pharmacology*
  • Rabbits
  • Rats
  • Receptors, Neurokinin-2
  • Receptors, Neurotransmitter / drug effects*
  • Structure-Activity Relationship


  • Peptide Fragments
  • Receptors, Neurokinin-2
  • Receptors, Neurotransmitter
  • Neurokinin A