Ifenprodil

Ifenprodil (NP-120), a cerebral vasodilator, is a noncompetitive NMDA receptor antagonist. Ifenprodil exerts high affinity at NR1A/NR2B receptors (IC₅₀=0.34 μM) over 400-fold than at NR1A/NR2A receptors (IC₅₀=146 μM)^[1]. Ifenprodil is an α1 adrenergic receptor antagonist. Ifenprodil inhibits GIRK (Kir3), reduces inward currents through the basal GIRK activity. Ifenprodil has reliable inhibitory effects against A/H1N1 strains (EC₅₀ of 6.6 µM). Ifenprodil has neuroprotective, anticonvulsant and antinociceptive effects. Ifenprodil can be used for the study of cerebrovascular diseases and peripheral arterial obliterative disease^[2][4]. In Vitro: The degree of inhibition seen with 100 μM Ifenprodil at NR1A/NR2A receptors is not altered by changes in the concentration of extracellular glycine. However, the inhibitory effect of 1 μM Ifenprodil at NR1A/NR2B receptors is reduced by increasing the concentration of glycine^[1].
In oocytes injected with mRNAs for GIRK1/GIRK2, GIRK2 or GIRK1/GIRK4 subunits, Ifenprodil (3 μM) reversibly reduces inward currents through the basal GIRK activity^[2].
Ifenprodil interacts with several other receptors, namely, serotonin (5-HT) subtype 1A, 5-HT2 and 5-HT3 receptors, and σ receptors at nanomolar concentrations and that it inhibits voltage-gated Ca²⁺ channels at micromolar concentrations^[2].
In Vivo: Ifenprodil (0.25-1.13 μmol; intrathecal injection; once) produces a dose-dependent local anesthetic effect in spinal anesthesia in rat^[3].