Nociceptin/Orphanin FQ System Modulation in Pain and Mental Health

The nociceptin/orphanin FQ (N/OFQ) system comprises the endogenous opioid-like peptide N/OFQ and its cognate receptor (NOP). This neuropeptide–receptor pair regulates nociceptive transmission, stress responses, mood and reward behaviours without typical opioid-induced respiratory depression or addiction liability. In peripheral tissues, N/OFQ influences immune cell migration and cytokine release, while centrally it modulates hypothalamic–pituitary–adrenal axis activity, anxiety and learning. Pharmacological targeting of NOP with selective agonists or antagonists has revealed analgesic efficacy in models of acute, chronic and neuropathic pain, as well as anxiolytic and antidepressant effects in preclinical paradigms. The system’s nuanced signalling—via G proteins, β-arrestins and biased agonism—offers an opportunity to uncouple beneficial antinociception from adverse effects. Growing evidence also implicates N/OFQ–NOP modulation in addiction circuits, highlighting its potential for novel treatments of substance use disorders and stress-related psychiatric conditions.

Research from Nature Portfolio

Recent studies have introduced NOPLight, a genetically encoded fluorescent sensor that reports endogenous N/OFQ release with high spatial and temporal precision. In vitro characterisation demonstrated its sensitivity, ligand selectivity and compatibility with live-cell and brain-slice preparations. In vivo fibre-photometry in freely behaving rodents revealed dynamic N/OFQ signalling in the ventral tegmental area during natural reward and stress paradigms, offering a tool to dissect peptide release in real time. Another key work defined the role of the N/OFQ–NOP system in nicotine reinforcement. In an operant co-administration model, NOP receptor agonism enhanced nicotine self-administration, whereas NOP antagonism reduced both nicotine and alcohol intake, emphasising endogenous N/OFQ as a critical modulator of addictive behaviours and a target for smoking cessation strategies.

Nociceptin/Orphanin FQ System Modulation in Pain and Mental Health publication trend

The graph below shows the total number of articles in nociceptin/orphanin fq system modulation in pain and mental health across all publications each year (not limited to Nature Index journals).

Technical terms

Nociceptin/Orphanin FQ (N/OFQ): Endogenous neuropeptide ligand for the NOP receptor involved in pain, stress and reward processing.

NOP receptor: G protein-coupled receptor activated by N/OFQ that modulates neuronal signalling and immune responses.

G protein-coupled receptor (GPCR): Membrane receptor that transduces extracellular signals via G proteins to intracellular effectors.

Agonist: Molecule that binds to a receptor to activate its downstream signalling cascade.

Antagonist: Molecule that binds to a receptor to inhibit its activation by endogenous ligands or other agonists.

References

1. Development of a genetically encoded sensor for probing endogenous nociceptin opioid peptide release. Nature Communications (2024).
2. A key role for the N/OFQ-NOP receptor system in modulating nicotine taking in a model of nicotine and alcohol co-administration. Scientific Reports (2016).
3. In vitro sepsis up‐regulates Nociceptin/Orphanin FQ receptor expression and function on human T‐ but not B‐cells. British Journal of Pharmacology (2023).
4. Nuclear Factor-κB Signaling Regulates the Nociceptin Receptor but Not Nociceptin Itself. Cells (2024).
5. Pharmacological Profile of Nociceptin/Orphanin FQ Receptors Interacting with G-Proteins and β-Arrestins 2. PLOS ONE (2015).
6. Spotlight on Nociceptin/Orphanin FQ Receptor in the Treatment of Pain. Molecules (2022).