Photodynamic-action-induced calcium oscillations and the effect of atropine and FK480. In (a), SALPC 1 μM, light (53,000 lx) was delivered as indicated by the horizontal bars. In (b), SALPC 1 μM, light (53,000 lx) and atropine 10 μM were delivered as indicated by the horizontal bars. In (c), SALPC 1 μM, light (53,000 lx) and FK480 10 nM were delivered as indicated by the horizontal bars. Note the complete blockade by FK480 of photodynamically induced calcium oscillations in (c). Traces (a), (b), and (c) are representative of seven, four, and four identical experiments.