McDonald J, Calo G, Guerrini R, Lambert D G
University Department of Anaesthesia, Critical Care and Pain Management, Leicester Royal Infirmary, LE1 5WW, Leicester, UK.
Naunyn Schmiedebergs Arch Pharmacol. 2003 Feb;367(2):183-7. doi: 10.1007/s00210-002-0661-8. Epub 2003 Jan 15.
Studies of the pharmacology of nociceptin/orphanin FQ (N/OFQ) and its receptor (NOP) have been hampered by the lack of a range of high potency antagonists. In this study we have examined the effects of a novel N/OFQ analogue [Nphe(1),Arg(14),Lys(15)]N/OFQ NH(2) hereafter referred to as UFP-101. [(3)H]N/OFQ competition binding and GTPgamma(35)S binding assays were performed using CHO cells expressing the human NOP receptor (CHO(hNOP)). UFP-101 (pK(i) of 10.14+/-0.09) and a range of NOP selective agonists displaced [(3)H]N/OFQ binding with the following rank order of affinity: [Arg(14),Lys(15)]N/OFQ>[( pF)Phe(4)]N/OFQ(1-13)NH(2)>N/OFQ(1-13)NH(2)>UFP-101>N/OFQ>Ro64-6198>[Nphe(1)]N/OFQ(1-13)NH(2). N/OFQ, N/OFQ(1-13)NH(2), [( pF)Phe(4)]N/OFQ(1-13)NH(2), [Arg(14),Lys(15)]N/OFQ and Ro64-6198 also produced a concentration dependent (pEC(50) values of 8.75+/-0.11, 9.28+/-0.15, 9.69+/-0.04, 9.12+/-0.11 and 8.09+/-0.07 respectively) and saturable stimulation of GTPgamma(35)S binding and all were full agonists. UFP-101 did not stimulate GTPgamma(35)S binding per se, but produced a concentration dependent and parallel rightward shift in the concentration response curves to all agonists. UFP-101 yielded pA(2) values in the range 8.4-9.0. For comparison a pA(2) for [Nphe(1)]N/OFQ(1-13)NH(2) (the template for UFP-101) against N/OFQ of 7.33+/-0.08 was obtained. Slope factors for the Schild regression lines were approximately 1 indicating competitivity. When UFP-101 is compared with its template molecule [Nphe(1)]N/OFQ(1-13)NH(2), Arg(14),Lys(15) substitution produced approximately 1 log greater potency. We suggest that due to its high potency UFP-101 should prove a further useful tool in the evaluation of the N/OFQ-NOP receptor system.
由于缺乏一系列高效拮抗剂，对孤啡肽/孤啡肽FQ（N/OFQ）及其受体（NOP）的药理学研究受到了阻碍。在本研究中，我们检测了一种新型N/OFQ类似物[Nphe(1),Arg(14),Lys(15)]N/OFQ NH₂（以下简称UFP-101）的作用。使用表达人NOP受体的CHO细胞（CHO(hNOP)）进行[(³H)]N/OFQ竞争结合和GTPγ³⁵S结合试验。UFP-101（pK(i)为10.14±0.09）和一系列NOP选择性激动剂以以下亲和力顺序取代[(³H)]N/OFQ结合：[Arg(¹⁴),Lys(¹⁵)]N/OFQ > [(pF)Phe(⁴)]N/OFQ(¹⁻¹³)NH₂ > N/OFQ(¹⁻¹³)NH₂ > UFP-101 > N/OFQ > Ro64-6198 > [Nphe(¹)]N/OFQ(¹⁻¹³)NH₂。N/OFQ、N/OFQ(¹⁻¹³)NH₂、[(pF)Phe(⁴)]N/OFQ(¹⁻¹³)NH₂、[Arg(¹⁴),Lys(¹⁵)]N/OFQ和Ro64-6198也产生了浓度依赖性（pEC(₅₀)值分别为8.75±0.11、9.28±0.15、9.69±0.04、9.12±0.11和8.09±0.07）且饱和的GTPγ³⁵S结合刺激，并且均为完全激动剂。UFP-101本身不刺激GTPγ³⁵S结合，但使所有激动剂的浓度反应曲线产生浓度依赖性和平行右移。UFP-101产生的pA₂值在8.4 - 9.0范围内。为作比较，获得了[Nphe(¹)]N/OFQ(¹⁻¹³)NH₂（UFP-101的模板）对N/OFQ的pA₂值为7.33±0.08。Schild回归线的斜率因子约为1，表明具有竞争性。当将UFP-101与其模板分子[Nphe(¹)]N/OFQ(¹⁻¹³)NH₂比较时，Arg(¹⁴)、Lys(¹⁵)取代使效力提高了约1个对数单位。我们认为，由于其高效力，UFP-101应可证明是评估N/OFQ - NOP受体系统的又一有用工具。
