Nociceptin/orphanin FQ up‐regulates P2X3 receptors in primary cultures of neonatal rat trigeminal ganglion neurons

Recent evidence indicates a nociceptive role of the nociceptin/orphanin FQ–opioid receptor‐like receptor (N/OFQ‐ORL1) system in craniofacial pain; however, the mechanisms of such an effect remain unclear. We investigated whether the action of N/OFQ involves the modulation of P2X₃, a pain‐transducing ionotropic receptor. Double‐labeled immunohistochemical staining was used to determine the co‐localization of ORL1 and P2X₃ receptors in the trigeminal ganglia (TG) of neonatal Sprague‐Dawley rats. The effect of N/OFQ (at a concentration ranging from 1 pM to 10 nM) on the expression of P2X₃ receptors was detected by RT‐PCR, western blotting, and immunocytochemical staining. We found that ORL1 receptors were co‐localized with P2X₃ receptors and that the application of N/OFQ could up‐regulate, in a concentration‐dependent manner, the expression of P2X₃ receptor mRNA and P2X₃ receptor protein in TG neurons. Immunocytochemical staining also revealed enhanced P2X₃ immunoreactivity beneath the neuronal membrane and an increased percentage of P2X₃‐positive neurons after treatment with N/OFQ. Those effects were completely blocked by a specific ORL1 antagonist, UFP‐101. Our results suggest that the activation of ORL1 receptors by N/OFQ can potentiate P2X₃ receptors in primary cultures of neonatal trigeminal neurons, which may be a mechanism for the nociceptive role of N/OFQ in the modulation of craniofacial pain. Our findings may also have implications in treating craniofacial pain.     

未成年人解脲支原体DNA检测

目的:为了解未成年人UU感染特点。方法:FQ PCR方法用于定量检测未成年人和成年人样本中的UU DNA。结果:未成年人UU DNA阳性率(28.57%,24/84)显著小于成年人(48.87%,2569/5257)(χ2=13.64,P=0.00022),而UU DNA载量(5.72±1.11)则高于成年人(4.69±1.42)(t=3.54,P=0.00040);未成年女性感染阳性率(31.51%,23/73)显著低于成年人(55.10%,2238/4062)(χ2=16.10,P=6.00E-5),而载量(5.71±1.14)则高于成年女性(5.00±1.52)(t=2.21,P=0.027)。两组男性感染率则无统计学差异(χ2=1.87,P=0.17)。结论:未成年人UU DNA感染率显著小于成年人,UU DNA载量则高于成年人。     

Recent advances towards the discovery of ORL-1 receptor agonists and antagonists

Since their discovery a decade ago, remarkable progress has been made toward understanding the biological function and significance of the opioid receptor-like-1 (ORL-1) receptor and its endogenous peptide ligand, nociceptin. The human nociceptin receptor, herein referred to as ORL-1, but also known as OP4 (the fourth member of opioid peptide receptor family) or nociceptin/orphanin FQ peptide (NOP) receptor, was first identified as an orphan opioid receptor with close homology to the classical μ-, κ-, and δ-opioid receptors. ORL-1 does not bind endogenous ligands of the other opioid receptors with high affinity, but instead prefers the 17 amino acid peptide nociceptin. The obvious homologies of ORL-1 to opioid receptors, and its ligand nociceptin to opioid peptide ligands, led to a period of intense investigation that resulted in a number of significant reports describing the biology of the receptor and ligand. The emerging pharmacological evidence from these reports suggests that ORL-1 agonists may be clinically useful for treatment of stress, anxiety, substance abuse (opioid and alcohol), anorexia, cachexia, cough, asthma, and possibly neuropathic pain/allodynia. The peripheral effects of nociceptin suggest that agonists may have utility in the treatment of gastrointestinal motility disorders, water retention, and hypertension. ORL-1 antagonists may be useful in enhancing cognitive function and treating locomotor disorders such as Parkinsonism. In addition to research into the fundamental biology of ORL-1 and nociceptin, noteworthy advances have been made in the discovery of new peptide and non-peptide agonists and antagonists of the ORL-1 receptor leading to a better understanding of its involvement in a variety of biological processes. This review highlights the rationale for the development of ORL-1 ligands and recent progress made by different research groups towards the development of peptidic and non-peptidic ORL-1 agonists or antagonists over the last four years. To add perspective on the commercial potential of this research area, the development status of advanced new molecules is addressed together with any pharmacological characterisation of these entities.     

冠脉结扎大鼠小肠孤啡肽表达的变化

目的观察结扎冠状动脉左前降支造成心肌缺血时大鼠小肠内孤啡肽(orphanin FQ)的表达变化。方法 54只雄性SD大鼠按随机数字表法分为三组:①正常对照组(n=6),麻醉后直接取材;②假手术组(sham组,n=24),只开胸暴露心脏不结扎冠脉;③结扎冠状动脉组(coronary artery occlusion group,CAO组,n=24),单纯扎闭冠状动脉左前降支。其中,sham组和CAO组又分为4个亚组:0.5 h组、1 h组、3 h组、6 h组,每亚组大鼠均为6只。采用免疫组化观察并分析结扎大鼠冠状动脉不同时点小肠组织内OFQ的表达变化情况;应用酶联免疫吸附技术对比分析不同时点小肠组织内OFQ的表达水平。结果免疫组化半定量分析结果显示,CAO后各时点(除0.5 h外)小肠黏膜和肌间神经丛OFQ的水平较正常对照组和同时点sham组显著升高(P<0.05);酶联免疫吸附技术结果显示CAO组小肠OFQ的水平较同时点sham组显著升高(P<0.05),CAO 3 h组表达达到高峰,与sham组比较差异有统计学意义(P<0.01)。结论急性心肌缺血时大鼠小肠内孤啡肽的表达增加,孤啡肽可能作为一种肠神经递质或调质来影响胃肠运动和分泌。     

M_1受体参与孤啡肽抑制大鼠顶叶皮质神经元延迟整流钾电流

目的研究M受体不同亚型对孤啡肽(N/OFQ)抑制大鼠顶叶皮质神经元延迟整流钾电流(IK)作用的影响。方法采用全细胞膜片钳技术,应用M受体不同亚型阻断剂,观察M受体亚型在孤啡肽抑制大鼠顶叶皮质神经元IK中的作用。结果 (1)N/OFQ对大鼠顶叶皮质神经元IK有抑制作用,抑制率为30.8%±5.6%(P<0.01)。(2)M1受体拮抗剂哌伦西平(PIR)可减弱N/OFQ对IK的抑制作用,在指令电压为+60 mV时,PIR+N/OFQ组的IK幅度下降了15.5%±2.5%,与单独给予N/OFQ所引起的IK抑制效应相比有显著差异(P<0.05)。(3)M3受体拮抗剂4DAMP拮抗N/OFQ对IK的抑制作用不明显。结论 M1受体参与N/OFQ对大鼠顶叶皮质神经元IK的抑制作用。     

The biology of Nociceptin/Orphanin FQ (N/OFQ) related to obesity,stress, anxiety,mood, and drug dependence

Nociceptin/Orphanin FQ (N/OFQ) is a 17 amino acid peptide that was deorphanized in 1995. The generation of specific agonists, antagonists and receptor deficient mice and rats has enabled progress in elucidating the biological functions of N/OFQ. Additionally, radio-imaging technologies have been advanced for investigation of this system in animals and humans. Together with traditional neurobehavioral techniques, these tools have been utilized to identify the biological significance of the N/OFQ system and its interacting partners. The present review focuses on the role of N/OFQ in the regulation of feeding, body weight homeostasis, stress, the stress-related psychiatric disorders of depression and anxiety, and in drug and alcohol dependence. Critical evaluation of the current scientific preclinical literature suggests that small molecule modulators of nociceptin opioid peptide receptors (NOP) might be useful in the treatment of diseases related to these biological functions. In particular, the literature data suggest that antagonism of NOP receptors will produce anti-obesity and antidepressant activities in humans. However, there are also contradictory data discussed. The current literature on the role of N/OFQ in anxiety and addiction, on the other hand points primarily to a role of agonist modulation being potentially therapeutic. Some drug-like molecules that function either as agonists or antagonists of NOP receptors have been optimized for human clinical study to test some of these hypotheses. The discovery of PET ligands for NOP receptors, combined with the pharmacological tools and burgeoning preclinical data set discussed here bodes well for a rapid advancement of clinical understanding and potential therapeutic benefit.     

The endogenous nociceptin/orphanin FQ‐NOP receptor system as a potential therapeutic target for intestinal disorders

In 1995, by reverse pharmacology approach, used here for the first time in the history of pharmacology, nociceptin/orphanin FQ (N/OFQ) has been discovered as the endogenous ligand of a preidentified receptor named opioid receptor like 1. Subsequent studies showed that N/OFQ and its receptor (N/OFQergic system) are widely distributed in central and peripheral nervous systems as well as in peripheral organs of human and animals, and represent a system that is involved in a very large range of biological functions such as pain perception, intestinal motility and secretion, immune modulation, stress. From the time of its discovery to now, a high number of NOP agonists and antagonists have been synthesized and tested in various pathologies. Nevertheless, none of the molecules targeting N/OFQergic system have currently succeeded in going through clinical trials concerning gut pathologies, indicating that further studies are required. The work from Dr. Fichna et al., published in the present issue of Neurogastroenterology and Motility, adds another brick in the wall of understanding the role of N/OFQergic system in IBS‐D pathology by the pharmacological evaluation of a new NOP receptor agonist, SCH 221510, in animal models of intestinal alterations (diarrhea and visceral hyperalgesia). Interestingly, authors report clinical data confirming the involvement of N/OFQergic system in IBS‐D patients and, consequently, suggest this system as a valuable therapeutic target for IBS‐D pathology. This minireview aims to give a brief summary of experimental and clinical studies focusing on the N/OFQergic system as pharmacological target for the therapeutic treatment of intestinal pathologies such as IBS and IBD.     

Acute myocardial ischemia up-regulates nociceptin/orphanin FQ in dorsal root ganglion and spinal cord of rats

Nociceptin/orphanin FQ (N/OFQ) possesses modulatory effects on somatic noxious signals in spinal cord, while the potential role in visceral nociception remains elusive. We designed this study to investigate the hypothesis that cardiac nociceptive signals from acute ischemic myocardium to the spinal cord are transmitted or modulated by mechanisms including N/OFQ. We examined the changes of N/OFQ and its mRNA in the dorsal root ganglia and spinal cord of upper thoracic segments innervating the heart of rats. Thoracic epidural anesthesia was performed to confirm neural mechanism underlying the changes. We observed that selective coronary artery occlusion significantly up-regulated N/OFQ and ppN/OFQ mRNA in the dorsal root ganglia and spinal cord. Thoracic epidural anesthesia abolished the changes in the expression of N/OFQ and its mRNA. The observations indicate that cardiac noxious neural afferent drive is responsible for the up-regulation of N/OFQ in the primary afferent neurons and intrinsic spinal neurons.     

孤啡肽与子宫内膜异位不孕的相关研究

目的探讨子宫内膜异位症(内异症)不孕患者血孤啡肽含量的变化及对生殖内分泌的影响.方法采用放射免疫法测定21例内异症不孕妇女(不孕组)、23例单纯输卵管阻塞不孕妇女(对照组)及30例健康妇女(正常组)血孤啡肽及卵泡刺激素(FSH)、黄体生成素(LH)的含量.结果 (1)不孕组妇女血孤啡肽及FSH、LH的含量分别为(29.61±6.33)ng.L-1 、(2.03±0.32)IU.L-1及(6.43±1.89)IU.L-1,对照组妇女血孤啡肽及FSH、LH的含量分别为(10.18±3.64)ng.L-1、(4.05±0 51)IU.L-1及(15.05±4.26)IU.L-1,正常组分别为(11.35±3.71)ng.L-1、(3.82±0.46)IU.L-1及(12.63±3.18)IU.L-1.(2)内异症不孕组妇女血孤啡肽水平显著高于对照组及正常组(P<0.01及P<0.05).(3)不孕组妇女血FSH、LH的含量显著低于对照组及正常组(P<0.01及P<0.05).(4)内异症不孕妇女血孤啡肽及FSH、LH水平显著负相关(P<0.05).结论孤啡肽与子宫内膜异位不孕的发生发展密切相关,其机理可能与抑制FSH及LH的分泌有关.