Fig. 3.

Average [Ca²⁺]_cyto (A) and simultaneously recorded developed LVP (B) for young and old hearts. Data are shown from 80 min into the experiment after dye loading and washout. After the stabilization period, no differences were noted between old and young hearts in developed LVP (85.2 ± 2.0 vs. 85.6 ± 1.7 mmHg; data not shown). The negative inotropic effects of indo-1 AM loading were greater in young hearts compared with old hearts as noted from the lower developed LVP after dye washout. Average [Ca²⁺]_cyto was lower in old hearts than in young hearts at REP 10 min but not at REP 60 min. Developed LVP was higher in old hearts than in young hearts at REP 10 min and at REP 60 min.