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Parallel bioassay of 39 tachykinins on 11 smooth muscle preparations. Structure and receptor selectivity/affinity
C Severini1, S Salvadori, R Guerrini
1CNR - Institute of Neurobiology, Viale C. Marx 15, I-00137, Rome, Italy. tindaro.renda@uniroma.it
Abstract:
Parallel bioassay on smooth muscle preparations demonstrated that: all TKs having a neutral or basic residue at position 7 from the C-terminus show a clear-cut preference for the NK1 TK receptor, reinforced by the presence of the aromatic doublet Phe-Phe or Phe-Tyr (aromatic TKs); all aliphatic TKs (Phe-Ile/Val) having an acidic residue at position 7 show a clear-cut preference for NK2/NK3 receptors, generally without selectivity for a single receptor. However, in aromatic TKs having the same acidic residue, the preference for NK2/NK3 receptors is weakened, with a more or less pronounced co-preference for the NK1 receptor. Amino acid substitutions in the C-terminal tripeptide may influence receptor affinity.
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