Fig. 5.

Fibers expressing Foxo1-GFP exhibit local Ca²⁺ responses. Control fibers expressing GFP (A, left) and fibers expressing Foxo1-GFP (B, left) were loaded with rhod-2 and their calcium responses to electrical stimulation were recorded. Time course of rhod-2 fluorescence in response to field stimulation (A and B, right). White boxes in A and B, left, show the regions of interest used to measure the calcium transients in response to electrical stimulation. GFP fibers responded to both polarities with calcium transients (A), whereas Foxo1-GFP fibers only responded locally to each polarity (B). C: bar plot summarizing differences in peak amplitude of rhod-2 ΔF/F₀ transient. GFP fibers = 10.44 ± 0.43, n = 17, N = 3; Foxo1-GFP fibers = 3.17 ± 0.21, n = 19, N = 3. N indicates number of mice per condition, and n indicates number of fibers tested. *P < 0.05, compared with control GFP fibers.