Figure 3. Aging reduces facilitation of Ca²⁺ release by FKBP12 but not by mTOR kinase in smooth muscle cells.

(A) Cells were stimulated with two pulses of caffeine (10 μM separated by a 15 min interval to apply inhibitors (indicated by horizontal lines) or normal medium (control trace). For the sake of comparison, the control trace in top left panel is shifted to the left. Traces are representative of the effects of KU0063794 (5 μM) or rapamycin (5 μM) on young (left column) or aged cells (right column). (B) Histogram summarizing the effects of the three inhibitors (KU: KU0063794, 5 μM; rapamycin 5 μM; FK506 10 μM) on the bethanechol (0.1 mM) and caffeine (10 mM) evoked Ca2+ responses in young and aged cells. Two-ways ANOVA showed significant effect for treatment (bethanechol: F = 22.4, p < 0.005; caffeine: F = 21.9, p < 0.005), which was modified by age (bethanechol: F = 4.0, p < 0.01; caffeine: F = 5.0, p < 0.01). Asterisks denote significance for planned comparisons between groups of interest. * p<0.05, ** p< 0.01, *** p< 0.005. n= 17-130 cells from 6 (aged) or 8 (young) animals.