Intracellular Mn2+ accumulation was correlated with neuronal activity in striatal GABAergic neurons.
(a) Fluorescence image of a striatal slice from a GAD67-GFP mouse. Striatal GABAergic neurons were identified by GFP fluorescence and ROIs were placed on the GFP-positive somata for quantification of the fluorescence changes. The tip of the stimulation electrode is indicated by asterisk (*). Scale bar, 50 μm. (b,c) Typical time course of the [Ca2+]i transient evoked by 20 pulses of 50-Hz stimulation before (b) and following 50 μM MnCl2 administration (c) obtained from the same cell. Dashed arrows indicate amplitude of the [Ca2+]i transient (b) or the amount of the Mn2+ quench (c). Stimulation period is indicated by thick horizontal line. (d) Comparison of the amplitude of the [Ca2+]i transient and the amount of Mn2+ quench of the fluorescence at 360 nm, when 20 pulses at 20 Hz (solid circle) or 50 Hz stimuli (open circle) were applied (n = 366 cells). r: Pearson’s correlation coefficient.