QAQ dichloride is a photoswitchable compound that blocks voltage-gated Na v and K v channels. Its channel-blocking activity is observed in the trans form of the azobenzene photoswitch, while the cis form does not exhibit this effect. This compound is membrane-impermeant and selectively enters pain-sensing neurons expressing endogenous import channels. QAQ dichloride functions as a light-sensitive analgesic and provides a valuable tool for investigating signaling mechanisms involved in acute and chronic pain [1] [2].

QAQ dichloride (100 μM), incapable of membrane penetration, is administrable into cells via micropipette for targeted photo-sensitization of individual cells, enabling precise manipulation of action potential dissemination. Its dual-action modulates Shaker-IR current, obstructing in the trans configuration while permitting flow in the cis configuration [1]. Furthermore, QAQ dichloride serves as a precursor for crafting red-shifted variants, potent photochromic blockers that facilitate optical control over K v and Na v channel conductance. These innovations present a method for reversibly silencing neuronal activity, heralding advancements in non-invasive neural modulation [2].