Gicquel S, Mazarguil H, Desprat C, Allard M, Devillers J P, Simonnet G, Zajac J M
Laboratoire de Pharmacologie et de Toxicologie Fondamentales, CNRS, Toulouse, France.
J Med Chem. 1994 Oct 14;37(21):3477-81. doi: 10.1021/jm00047a005.
Twenty neuropeptide FF (NPFF) analogs having various lengths were synthesized by solid-phase peptide synthesis to gain more information on the role of N-terminal residues for the NPFF receptor affinity. The affinities were evaluated in the rat spinal cord membrane preparations, and the biological activities were measured on morphine analgesia in the mouse tail-flick test. Shortening of the NPFF sequence from the N-terminal produced only a moderate decrease in affinity until NPFF (4-8) was reached. In the same way, NPFF(3-8) significantly decreased morphine analgesia, while NPFF(4-8) had no significant effect at a dose of 22 nmol. The introduction in the N-terminal part of NPFF of a D-enantiomer at positions 2 and 1 or the presence of an N-methyl group on position 3 did not modify affinity and activity. Substitution of proline5 by the D-isomer decreased the affinity of NPFF analogs whatever their length, and [Tyr1,D-Pro5]NPFF(1-8) was 2.5-fold less potent than [Tyr1]NPFF(1-8) in reversing morphine-induced analgesia. In contrast, the presence of a glycine residue in position 5 did not influence the affinity toward NPFF receptors. Data provide evidence that the N-terminal segment of neuropeptide FF is responsible for high-affinity binding.
通过固相肽合成法合成了20种不同长度的神经肽FF（NPFF）类似物，以获取更多关于N端残基对NPFF受体亲和力作用的信息。在大鼠脊髓膜制剂中评估了亲和力，并在小鼠甩尾试验中测定了对吗啡镇痛的生物活性。从N端缩短NPFF序列，直到达到NPFF（4-8），亲和力才出现适度下降。同样，NPFF（3-8）显著降低吗啡镇痛作用，而NPFF（4-8）在22 nmol剂量时无显著作用。在NPFF的N端部分，第2位和第1位引入D-对映体或第3位存在N-甲基，均不改变亲和力和活性。无论NPFF类似物长度如何，用D-异构体取代脯氨酸5都会降低其亲和力，且在逆转吗啡诱导的镇痛作用方面，[Tyr1,D-Pro5]NPFF(1-8)的效力比[Tyr1]NPFF(1-8)低2.5倍。相反，第5位存在甘氨酸残基不影响对NPFF受体的亲和力。数据表明神经肽FF的N端片段负责高亲和力结合。
