| In vitro |
A-803467 potently blocks recombinant human or rat NaV1.8 channels with IC50 of 8 nM and 45 nM, respectively, at a holding potential of -40 mV. At a resting state, A-803467 also potently blocks human NaV1.8 channels with IC50 of 79 nM. A-803467 blocks tetrodotoxin-resistant (TTX-R) currents in rat dorsal root ganglion neurons in a concentration-dependent manner with IC50 of 140 nM, more potently compared with both mexiletine and lamotrigine with IC50 of >30 μM. A-803467 displays 300- to 1,000-fold higher selectivity for hNaV1.8 over hNaV1.2, hNaV1.3, hNaV1.5, and hNaV1.7 channels with IC50 of 7.38 μM, 2.45 μM, 7.34 μM, and 6.74 μM, respectively. A-803467 shows no significant activity against other channels and receptors expressed in peripheral sensory neurons including TRPV1, P2X2/3, CaV2.2 and KCNQ2/3 channels with IC50 >10 μM. A-803467 also shows no or weak activity against a broad screening panel of cell-surface receptors, ion channels, and enzymes with IC50 of >2 μM. A-803467 at 0.3 μM but not 0.1 μM significantly inhibits the generation of spontaneous and electrically evoked action potentials. [1]
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| In vivo |
Consistent with its effects on neuronal action potential electrogenesis in vitro, systemic administration of A-803467 (20 mg/kg, i.v.) to spinal nerve ligated rats, significantly reduces both spontaneous and von Frey hairevoked firing of spinal dorsal horn wide dynamic range neurons by 66% and 53%, respectively, compared with baseline levels. Administration of A-803467 also dose-dependently reduces mechanical allodynia in a variety of rat pain models including spinal nerve ligation (ED50 = 47 mg/kg, i.p.), sciatic nerve injury (ED50 = 85 mg/kg, i.p.), capsaicin-induced secondary mechanical allodynia (ED50 ≈ 100 mg/kg, i.p.), and thermal hyperalgesia after intraplantar complete Freund's adjuvant injection (ED50 = 41 mg/kg, i.p.). A-803467 is inactive against formalin-induced nociception and acute thermal and postoperative pain, as well as in a chemotherapy-induced pain model (vincristine). [1]
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COA
HPLC