A Visible-Light-Sensitive Caged Serotonin

Serotonin, or 5-hydroxytryptamine (5HT), is an important neurotransmitter in the nervous system of both vertebrates and invertebrates. Deficits in 5HT signaling are responsible for many disabling psychiatric conditions, and its molecular machinery is the target of many pharmaceuticals. We present a new 5HT phototrigger, the compound [Ru(bpy) 2 (PMe 3 )(5HT)] 2+, where PMe 3 is trimethylphosphine. As with other ruthenium-bipyridyl based caged compounds, [Ru(bpy) 2 (PMe 3 )(5HT)] 2+ presents activity in the visible region of the spectrum. We characterize and discuss the photochemical properties of the caged compound, and demonstrate its use by modulating the excitability of mouse prefrontal principal neurons.