Fast biology can be used to test the rate of uncaging.
a) Glutamate release from MNI-Glu, unlike CNB-Glu, using time-resolved absorption analysis is not well characterized; b) However, 2-photon photolysis (2PP) of MNI-Glu with short pulses (50 μs) of 720 nm light produces rapid responses at spine heads (red), which mimic naturalistic responses (mEPSC, black), the time to peak was 0.5 ms[34]. Such data demonstrate fast biology can be used to estimate release rates; c) Cartoons of focal 2-photon uncaging at glutamate receptors on a spine head (left), and Ca2+-driven single vesicle fusion, causing the mEPSC currents shown above (right). mEPSC - miniature post-synaptic excitatory current. Part b) adapted from ref. 34, copyright 2001 GCRE-D.