Related Experiment Video
Updated: Jul 20, 2026
07:36
Analysis of Raw and Processed Cyperi Rhizoma Samples Using Liquid Chromatography-Tandem Mass Spectrometry in Rats with Primary Dysmenorrhea
Published on: December 23, 2022
Prostaglandin E2 receptor EP4 contributes to inflammatory pain hypersensitivity
Chung-Ren Lin1, Fumimasa Amaya, Lee Barrett
1Department of Anesthesiology, Chang Gung Memorial Hospital, Kaohsiung Medical Center, Chung Gang University, Taiwan, Republic of China.
The Journal of Pharmacology and Experimental Therapeutics
|September 13, 2006
Summary
Prostaglandin E2 (PGE2) EP4 receptor in sensory neurons is upregulated during inflammation. Blocking EP4 alleviates inflammatory pain hypersensitivity, suggesting it as a therapeutic target.
Area of Science:
- Neuroscience
- Immunology
- Pharmacology
Background:
- Prostaglandin E2 (PGE2) acts as an inflammatory mediator and neuromodulator.
- PGE2 effects are mediated by four G-protein-coupled EP receptors (EP1-EP4).
Purpose of the Study:
- To investigate the role of EP4 receptor in inflammatory pain sensitization.
- To determine if EP4 receptor expression changes in dorsal root ganglion (DRG) neurons during inflammation.
Main Methods:
- Assessed EP4 receptor expression in DRG neurons following peripheral inflammation.
- Utilized an EP4 antagonist (AH23848) and EP4 knockdown via short hairpin RNA (shRNA) to block EP4 function.
- Evaluated behavioral hypersensitivity to thermal and mechanical stimuli in an inflammation model.
- Measured capsaicin-evoked currents in DRG neurons in vitro.
Main Results:
- EP4 receptor, but not EP1-3, is expressed by a subset of DRG neurons and its levels increase during inflammation.
- Administration of an EP4 antagonist and EP4 knockdown attenuated inflammation-induced thermal and mechanical hypersensitivity.
- Basal pain sensitivity remained unchanged.
- EP4 antagonism reduced PGE2-mediated sensitization of capsaicin-evoked currents in DRG neurons.
Conclusions:
- EP4 receptor plays a critical role in mediating inflammatory pain hypersensitivity.
- EP4 receptor is a promising therapeutic target for managing inflammatory pain.
Related Concept Videos
01:20Drugs for Peptic Ulcer Disease: Prostaglandin Analogs as Mucosal Protective Agents
The gastric mucosa produces prostaglandins E2 (PGE2) and prostacyclin (PGI2), crucial in maintaining gastric health. They exert cytoprotective effects, including increasing bicarbonate secretion, releasing protective mucin, reducing gastric acid output, and preventing harmful vasoconstriction. These effects are mediated through various receptors, such as EP1, EP2, EP3, and EP4.
Non-steroidal anti-inflammatory drugs (NSAIDs) can induce peptic ulcers by inhibiting cyclooxygenase, decreasing...
Non-steroidal anti-inflammatory drugs (NSAIDs) can induce peptic ulcers by inhibiting cyclooxygenase, decreasing...
01:25Analgesia and Pain Management
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...
01:23Treatment for Pulmonary Arterial Hypertension: Prostacyclin Receptor Agonists
Prostacyclin receptor agonists are a class of therapeutic agents integral to managing pulmonary arterial hypertension (PAH). These drugs operate by mimicking the action of prostaglandin I2, or PGI2, a naturally occurring compound in the body.
These agonists bind to the IPR receptor situated on the plasma membrane of the pulmonary artery smooth muscle cells. This binding triggers a cascade of reactions known as the GS-AC-cAMP-PKA pathway. This pathway results in the relaxation of smooth muscle...
These agonists bind to the IPR receptor situated on the plasma membrane of the pulmonary artery smooth muscle cells. This binding triggers a cascade of reactions known as the GS-AC-cAMP-PKA pathway. This pathway results in the relaxation of smooth muscle...
01:25Acute Inflammation III: Local and Systemic Effects
Acute inflammation produces a coordinated set of local and systemic changes that limit injury, eliminate pathogens, and initiate repair. These responses arise within minutes of infection, trauma, or chemical insult and are driven by vascular alterations and leukocyte-derived mediators. When the stimulus resolves, the reaction typically abates within days.Local EffectsAt the site of injury, arteriolar vasodilation increases blood flow, resulting in redness and warmth. Simultaneously, increased...
01:22Opioid Receptors: Overview
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, D-Pen5]-enkephalin or DPDPE for...
01:09GPCRs Regulate Adenylyl Cylase Activity
Some GPCRs transmit signals through adenylyl cyclase (AC), a transmembrane enzyme. AC helps synthesize second messenger cyclic adenosine monophosphate (cAMP). AC catalyzes cyclization reaction and converts ATP to cAMP by releasing a pyrophosphate. The pyrophosphate is further hydrolyzed to phosphate by the enzyme pyrophosphatase, which drives cAMP synthesis to completion. However, cAMP is rapidly degraded to 5′ AMP by the enzymes phosphodiesterase (PDE), preventing overstimulation of cells.
Two...
Two...