QX 314 bromide is a positively charged, membrane-impermeable quaternary lidocaine derivative [1][2][3][4].
QX 314 bromide is a local anesthetic. In CAl pyramidal neurons of the guinea-pig hippocampal slice, QX 314 bromide blocked both Na+ dependent action potentials and the voltage-dependent, non-inactivating Na+ conductance [1]. In Xenopus laevis oocytes expressed TRPV1 and TRPV4 channels, QX 314 bromide (10, 30, and 60 mM) activated TRPV1 channels, but not TRPV4 channels. QX 314 bromide at lower concentrations (less than 1mM) potently inhibited capsaicin-evoked TRPV1 currents with IC50 value of 8.0 μM. In TRPV1-expressing tsA201 cells, QX 314 bromide induced transient increase in cytoplasmic Ca2+ [2]. In large-diameter human DRG neurons, flagellin/QX 314 bromide inhibited sodium currents [3].
In three standard local anesthetic animal models, QX 314 bromide reversibly and concentration-dependently induced long-lasting local anesthesia with a slow onset [4]. Intraplantar co-application of flagellin/QX 314 bromide inhibited mechanical allodynia after nerve injury, chemotherapy and diabetic neuropathy in a dose-dependent way. In naive and chemotherapy-treated mice, co-application of flagellin/QX 314 bromide selectively inhibited Aβ-fiber conduction [3].
References:
[1]. Connors BW, Prince DA. Effects of local anesthetic QX 314 bromide on the membrane properties of hippocampal pyramidal neurons. J Pharmacol Exp Ther, 1982, 220(3): 476-481.
[2]. Rivera-Acevedo RE, Pless SA, Ahern CA, Schwarz SK. The quaternary lidocaine derivative, QX 314 bromide, exerts biphasic effects on transient receptor potential vanilloid subtype 1 channels in vitro. Anesthesiology, 2011, 114(6): 1425-1434.
[3]. Xu ZZ, Kim YH, Bang S, et al. Inhibition of mechanical allodynia in neuropathic pain by TLR5-mediated A-fiber blockade. Nat Med, 2015, 21(11): 1326-1331.
[4]. Lim TK, Macleod BA, Ries CR, et al. The quaternary lidocaine derivative, QX 314 bromide, produces long-lasting local anesthesia in animal models in vivo. Anesthesiology, 2007, 107(2): 305-311.
