Figures 2.

A. Format and paradigm same as in Figure 1A except that in the second exposure 100 μM of ADO was included with the 100 μM ACh. Compared to the second exposure in Figure 1A, the decline in [Ca²⁺]_i in this second exposure seems to be much less. Cf. text. 2B. Summary of the 35 cells treated in the manner presented in Figure 2A. The decline in [Ca²⁺]_i in the second challenge with the 100 μM ADO is not statistically significant, whereas the [^Ca2+]_i decline in the third exposure to ACh is significantly lower than either of the first two exposures. 2C. Summary of the increases between the peak RLU value above the baseline value of 1.0. As in Figure 2B the first two differences do not differ from each; both do from the third.