What is QAQ?Ammonium–azobenzene–quaternary ammonium

(QAQ)A molecule devoloped at UC BerkeleyHas 2 sides, cis and transThe trans side is very similar to Lidocaine and is a

straight chain in structure, blocking the ion channels that send pain signals

The cis side is inactive and is bent in an L-shaped form.

QAQ slowly reverts to the trans side, which can be achieved much more quickly by…

LightNot just any old light.500 nm will accelerate this processUltraviolet light reactivates the neurons

All well and good but…

What makes lidocaine effective in dentists is it can cross cell membranes. But can QAQ do the same?

Rodent experiment.

So not quite like LidocaineHowever, this lack of permeability gives QAQ

the potential to be a selective anesthetic in a way Lidocaine is not. (ie numbing entire face)

TRPV1An Ion channel found in nociceptive neuronsAllowing QAQ to enter the nervesActivated by a chemical called Capsaicin

Capcaisin making the TRPV1 dilate allows entry for a bigger molecule like QAQ into the channel

The absence of TRPV1 in other nerves makes it possible to selectively target the nerves sensing pain

Turned on and off with a flick of a lightswitch!