NCIt definition : The hydrochloride salt form of fentanyl, a synthetic, lipophilic phenylpiperidine
opioid agonist with analgesic and anesthetic properties. Fentanyl selectively binds
to the mu-receptor in the central nervous system (CNS) thereby mimicking the effects
of endogenous opiates. Stimulation of the mu-subtype opioid receptor stimulates the
exchange of GTP for GDP on the G-protein complex and subsequently inhibits adenylate
cyclase. This results in a decrease in intracellular cAMP and leads to a reduction
in the release of neurotransmitters such as substance P, GABA, dopamine, acetylcholine
and noradrenaline. The analgesic effect of fentanyl is likely due to its metabolite
morphine, which induces opening of G-protein-coupled inwardly rectifying potassium
(GIRK) channels and blocks the opening of N-type voltage-gated calcium channels, thereby
resulting in hyperpolarization and reduced neuronal excitability.;
Semantic type(s)