Overview
- Alijevic, O. and Kellenberger, S. (2012) J. Biol. Chem. 287, 36059.
Alomone Labs GMQ hydrochloride modulates ASIC3 channels expressed in Xenopus oocytes.Time course of ASIC3 currents elicited by stimulation with pH 6 every 50 sec, while membrane potential was held at -60 mV. 0.5 mM GMQ hydrochloride (#G-165), applied for 3.5 min, as indicated causes reversible complex effect combining peak amplitude depression with diminished inactivation, as seen with superimposed traces in B.
2-guanidine-4-methylquinazoline (GMQ) is a small synthetic nonproton molecule that activates ASIC channels (acid-sensing ion channels). ASICs are proton-gated ion channels which are activated by a decrease in extracellular pH. GMQ is an activator of ASIC3 channels under physiological pH conditions; it induces a window current at pH 7.4 only in ASIC3. Evidence shows that GMQ alters the pH dependence of all ASIC subtypes studied1,2.
GMQ contains basic groups that seem to form tight contacts with the carboxyl groups of acidic residues through hydrogen bonds (H-bonds) and electrostatic interactions that lead to the activation of ASIC3. In addition, GMQ contains a guanidinium group and a heterocyclic ring.
Additional studies showed that GMQ activates sensory neurons and causes pain-related behaviors in an ASIC3-dependent manner3.
