Fig. 7. Aging increases the frequency of endfoot mitochondrial Ca²⁺ events.

a AAV-GfaABC1D-mito7-GCaMP6f was injected into the DLS of young and aging mice. 3 weeks later, intraventricular injection of tomato lectin (TL) was performed, and striatal brain sections were collected for recording and measuring Ca²⁺ influx events in endfoot mitochondria within the DLS. b Representative t-stacks of mitochondrial Ca²⁺ influx events detected by mito7-GCaMP6f (green) in young and aging astrocyte endfeet immediately adjacent to TL labeled blood vessels (red) in the DLS, scale bar = 15 μm. White arrows point to areas where mitochondrial endfoot Ca²⁺ events initiated. c Representative endfoot mitochondrial Ca²⁺ influx event traces from young (red) and aging (blue) mice. d Bar graphs showing the number (left) and area (right) of endfoot mitochondrial Ca²⁺ event ROIs in young and aging mice. e ROIs were averaged across individual blood vessels to compare endfoot mitochondria Ca²⁺ event frequency (left), amplitude (middle), and duration (right) in young and aging mice. For young mice, n = 53 ROIs and 18 blood vessels from 3 mice. For aging mice, n = 28 ROIs and 16 blood vessels from 5 mice. Error bars are S.E.M and all p values in (d) are based on Mann-Whitney test. In (e), frequency and amplitude p values are based on two-sample t-tests and the duration panel p value is based on a Mann-Whitney test.