Related Experiment Video
Updated: Mar 25, 2026
09:03
Optimizing Photoneuromodulation Techniques to Evaluate the Role of Green Light-Emitting Diodes in Pain Management
Published on: March 28, 2025
1.2K
Central N/OFQ-NOP Receptor System in Pain Modulation
Norikazu Kiguchi1, Huiping Ding1, Mei-Chuan Ko1
1Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA.
Advances in Pharmacology (San Diego, Calif.)
|February 28, 2016
Summary
Nociceptin/orphanin FQ (N/OFQ) and its receptor (NOP) system modulates pain differently in rodents and primates. NOP agonists offer potential safe analgesics, unlike traditional opioids, with fewer side effects in humans.
Area of Science:
- Neuroscience
- Pharmacology
- Pain Research
Background:
- The nociceptin/orphanin FQ (N/OFQ) peptide and its cognate (NOP) receptor were discovered two decades ago.
- NOP receptor activation shares intracellular signaling pathways with mu-opioid (MOP) receptors.
- NOP receptor-mediated pain modulation is complex and differs significantly between species.
Purpose of the Study:
- To review functional evidence on the role of NOP receptor agonists in pain modulation.
- To compare the effects of NOP receptor agonists in rodents and nonhuman primates.
- To evaluate the therapeutic potential and safety profile of NOP receptor agonists as analgesics.
Main Methods:
- Review of functional evidence from studies on spinal, supraspinal, and systemic administration of NOP receptor agonists.
- Analysis of pain modulation effects across different doses, assays, and pain modalities in rodents.
- Examination of NOP receptor agonist effects in nonhuman primates, including side effect profiles.
Main Results:
- Rodent studies show bidirectional pain modulation by NOP receptor agonists, dependent on dose and pain type.
- Nonhuman primate studies consistently demonstrate antinociception and antihypersensitivity with NOP receptor agonists.
- NOP receptor agonists and some bifunctional agonists lack abuse liability, respiratory depression, and gastrointestinal side effects in primates.
Conclusions:
- NOP receptor agonists exhibit a wider therapeutic window than MOP receptor agonists in primates.
- Bifunctional NOP/MOP receptor agonists require further investigation for their side effect profiles.
- Selective NOP receptor agonists and bifunctional agonists show promise as safe and effective analgesics for human use.
Related Concept Videos
01:44Nociception
34.3K
Nociception—the ability to feel pain—is essential for an organism’s survival and overall well-being. Noxious stimuli such as piercing pain from a sharp object, heat from an open flame, or contact with corrosive chemicals are first detected by sensory receptors, called nociceptors, located on nerve endings. Nociceptors express ion channels that convert noxious stimuli into electrical signals. When these signals reach the brain via sensory neurons, they are perceived as pain.
34.3K
01:22Opioid Receptors: Overview
6.3K
Opioid receptors, including the mu (μ, MOR), delta (δ, DOR), and kappa (κ, KOR) types, belong to the rhodopsin family of G protein-coupled receptors. These receptors are located throughout the central and peripheral nervous systems and in non-neuronal tissues such as macrophages and astrocytes. Opioid receptor ligands can be categorized into agonists or antagonists. Highly selective agonists include [d-Ala2, MePhe4, Gly(ol)5]-enkephalin or DAMGO for MOR, [D-Pen2,...
6.3K
01:25Analgesia and Pain Management
2.8K
Pain is critical to various clinical pathologies, provoking an urgent need for effective management. Pain, whether acute or chronic, is a complex neurochemical process. Its alleviation depends on the type, with nonopioid analgesics effective for mild to moderate pain, such as musculoskeletal or inflammatory pain, while neuropathic pain responds best to anticonvulsants, tricyclic antidepressants, or serotonin/norepinephrine reuptake inhibitors. For severe acute or chronic pain, opioids may be...
2.8K
01:20Pain
1.8K
Pain serves as a critical warning signal that alerts the body to potential or actual harm. When mechanical pressure on the skin is intense, such as from a sharp pinch, the sensation transitions from touch to pain. Similarly, extreme temperatures, like a hot pot handle, convert the sensation of heat into pain. Pain can also result from overstimulation of other senses, such as blinding light, loud noise, or the intense heat from habañero peppers. This ability to sense pain is essential for...
1.8K
01:43Thermosensation
35.0K
Peripheral thermosensation is the perception of external temperature. A change in temperature (on the surface of the skin and other tissues) is detected by a family of temperature-sensitive ion channels called Transient Receptor Potential, or TRP, receptors. These receptors are located on free nerve endings. Those detecting cold temperatures are closer to the surface of the skin than the nerve endings detecting warmth. These thermoTRP channels, while temperature selective, have relatively...
35.0K
01:11Sensory Perception: Organization of the Somatosensory System
12.0K
The somatosensory system is the central and peripheral nervous system component that senses and processes touch, pressure, pain, temperature, and body position or proprioception. The process of sensation takes place at three levels:
The receptor level:
The receptor level is the first stage of sensation. It involves the detection of a stimulus by specialized sensory receptors. The stimulus must arrive within the receptor's receptive field. Next, the receptor converts the energy of the...
The receptor level:
The receptor level is the first stage of sensation. It involves the detection of a stimulus by specialized sensory receptors. The stimulus must arrive within the receptor's receptive field. Next, the receptor converts the energy of the...
12.0K