Uncaging Calcium in Neurons

Abstract

Changes in intracellular free calcium concentration (Δ[Ca²⁺]_i) driving physiological events such as neurotransmitter release or Ca²⁺-dependent currents can be monitored using Ca²⁺-sensitive fluorescent dyes. Although these dyes can correlate Δ[Ca²⁺]_i with a physiological event, they cannot directly test for causality between changes in [Ca²⁺]_i and that event. Photolabile Ca²⁺ chelators are Ca²⁺-binding molecules that can alter and, to a certain extent, control [Ca²⁺]_i in an inducible manner and with temporal and spatial resolution that surpasses microinjection or ionophore application. Here we discuss the properties of caged Ca²⁺ compounds as well as some practical considerations for their use in neuronal cells, where they have proven particularly effective.