Fulgazepam: A Fulgimide-Based Potentiator of GABAA Receptors

The γ-aminobutyric acid gated chloride channel represents the major mediator of inhibitory neurotransmission in the mammalian central nervous system and its dysfunction is related to severe diseases like epilepsy and depression, which can be relieved by the application of allosteric modulators. However, the drugs’ potential side-effects limit their application for long-term treatment. Applying light as external stimulus to modify the pharmacophore’s activity, as emerged in the field of photopharmacology, provides a non-invasive tool with high spatial and temporal resolution for the modulation of protein function. Herein, we report the design, synthesis, and biological evaluation of photochromic fulgimide-based benzodiazepine derivatives as light-controllable potentiators of GABA_A receptors (GABA_ARs). A photocontrolled potentiator of GABA_ARs (Fulgazepam) has been identified that does not display agonist or antagonist activity and allows manipulating zebrafish larvae swimming.