Photolabile glutamate protecting group with high one- and two-photon uncaging efficiencies.

A pi-extended [2-(2-nitrophenyl)propoxy]carbonyl (NPPOC) derivative has been prepared as an efficient UV and near-IR photolabile protecting group for glutamate. This glutamate cage compound exhibits efficient photorelease upon one-photon excitation (epsilonPhi=990 M(-1) cm(-1) at 315 nm). In addition, it also shows efficient photorelease in activation of glutamate receptors in electrophysiological recordings. Combined with a high two-photon uncaging cross-section (deltaPhi=0.45 GM at 800 nm), its overall properties make this new cage-3-(2-propyl)-4'-methoxy-4-nitrobiphenyl (PMNB)-for glutamate a very promising tool for two-photon neuronal studies.