Confocal microscopic imaging of fast UV-laser photolysis of caged compounds

Using a pulsed UV laser in a confocal scanning microscope, we present a relatively cheap, accurate and efficient method for fast UV laser flash photolysis of caged molecules in two-dimensional cultured neurons. The laser light is introduced through the imaging optics, can be localized by a parallel red laser and can photolyse a sphere of less than 1μm², and evoke local fluorescence changes in the imaged neurons. Caged glutamate and caged fluorescein are used to illustrate a disparity between spines and their parent dendrites at a sub-micron resolution.