Calcium imaging in adult mouse spinal cord slices. Ratiometric images of dorsal horn before ( A) and during ( B) a 10 s exposure to 1 mM glutamate. Pseudocolor images show values of the 340/380 ratio where blue indicates basal Ca2+ levels and green/red indicate a glutamate-evoked Ca2+ increase. C. Glutamate-evoked Ca2+ traces evoked in panels A and B. The red trace represents an SR-101 positive cell indicated by the red arrowhead in A and B and the green traces represent SR-101 negative cells indicated by green arrows. Numbers on green arrows correspond to numbered traces in panel C. D. Numerous cells bulk loaded with Fura-2 AM are indicated by white arrowheads. A double-labeled astrocytic cell is indicated by a red arrowhead. E. Astrocyte labeling pattern with SR-101 in the same adult spinal cord slice. F. Merged image shows that the majority (~95%) of Fura-2 AM loaded cells are non-astrocytic.