Figure 2. Aging inhibits the mobilization of Ca2+ stores in colonic smooth muscle cells. (A) Isolated cells were challenged with a short pulse of bethanechol (0.1 mM) or caffeine (10 mM) to release Ca2+ from intracellular pools through IP3R and RyR channels, respectively. Traces are representative of average responses in young and aged cells. (B) Average ± sem response (ΔF340/F380) from young (8 animals, 117 and 165 cells) and aged (6 animals, 188 and 286 cells) guinea pigs.