Figure 4.

Enhanced Mn²⁺ quenching of Fura-2 fluorescence during H₂O₂ is reduced with advanced age

A, representative Fura-2 recording at isosbestic wavelength (360 nm) during superfusion with 2 mm MnCl₂ (replacing CaCl₂ in PSS) of endothelium from Young and Old mice at rest. Note similar rates of Fura-2 quench. B, summary data (means ± SEM) indicate no difference in Mn²⁺ influx between endothelium of Young (n = 6) and Old (n = 8) mice. C, as in A during exposure to 200 μm H₂O₂. Note increased rate of Fura-2 quench in both age groups compared to A with greater rate in Young versus Old. D, summary data (means ± SEM) indicate greater rate of Mn²⁺ influx in endothelium of Young (n = 6) versus Old (n = 6) during exposure to 200 μm H₂O₂. *P < 0.05, Old versus Young.