Fig. 4.

A: typical examples of the effect of nifedipine (1 μM) and nickel (30 μM) on the carbachol-induced Ca²⁺ transients. B: initial response to carbachol is shown in normal Ca²⁺ after which the cell was exposed to Ca²⁺-free external solution. Note the fall in basal fluorescence in the absence of external Ca²⁺; however, the cell was still able to respond to carbachol by firing a Ca²⁺ transient. C: summary data for the effect of nifedipine (n = 14), nickel (n = 7), and Ca²⁺-free (n = 7). *Statistical significance.