Fentanyl subject has role opioid receptor agonist
Mechanism of action
Fentanyl, like other opioids, acts on opioid receptors. These receptors are G-protein-coupled receptors, which contain seven transmembrane portions, intracellular loops, extracellular loops, intracellular C-terminus, and extracellular N-terminus. The extracellular N-terminus is important in differentiating different types of binding substrates. When fentanyl binds, downstream signaling leads to the inhibitory effects, such as decreased cAMP production, decreased calcium ion influx, and increased potassium efflux. This inhibits the ascending pathways in the central nervous system to increase pain threshold by changing the perception of pain; this is mediated by decreasing propagation of nociceptive signals, resulting in analgesic effects.As a μ-receptor agonist, fentanyl binds 50 to 100 times more potently than morphine. It can also bind to the delta and kappa opioid receptors but with a lower affinity. It has high lipid solubility, allowing it to more easily penetrate the central nervous system. It attenuates "second pain" with primary effects on slow-conducting, unmyelintated C-fibers and is less effective on neuropathic pain and "first pain" signals through small, myelinated A-fibers.Fentanyl can produce the following clinical effects strongly, through μ-receptor agonism:
Supraspinal analgesia (μ1)
Respiratory depression (μ2)
Physical dependence
Muscle rigidityIt also produces sedation and spinal analgesia through Κ-receptor agonism.
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