Fig. 5.

The involvement of intracellular Ca²⁺ stores in the effect of FCCP on AH/Type-II neurons. Drugs are added as indicated by the horizontal bars; the number of action potentials that are elicited is indicated under each stimulus. A, Effect of FCCP after blockade of the ATP-dependent Ca²⁺ pump with thapsigargin (2 μm). The AH is abolished almost completely after the thapsigargin treatment. Action potentials in the presence of FCCP induce only a small hyperpolarization.B, The effect of FCCP in the presence of ryanodine (10 μm). Ryanodine was applied 200 sec before the addition of FCCP. The FCCP-induced hyperpolarization develops slower than in the absence of ryanodine. C, The average amplitude ± SEM of the hyperpolarization induced by FCCP alone and in the presence of ryanodine. D, The average time ± SEM to reach the maximum hyperpolarization. In the presence of ryanodine the hyperpolarizing effect of FCCP is delayed significantly. The number of neurons per condition is indicated in the bars. Significant differences (p < 0.05) are indicated with an asterisk.