Bis-Q

Bis-Q is an acetylcholine (ACh) agonist that targets voltage-clamped muscle fibers of the fish Xenomystus nigris. Bis-Q exists in two forms: cis-Bis-Q (non-agonist) and trans-Bis-Q (agonist) . Photoisomerization converts cis-Bis-Q to trans-Bis-Q, which induces agonist-induced currents. Channels activated by trans-Bis-Q and ACh have similar conductances and open times. Flashes increase the ratio of trans-Bis-Q to cis-Bis-Q until light equilibrium is reached. Further flashes transiently increase agonist-induced currents, indicating binding of trans-Bis-Q to desensitized receptors. Higher concentrations of cis-Bis-Q produce larger agonist-induced currents that decay exponentially.[1].