Figure 6.

Effects of nifedipine and BayK-8644 on three spontaneously firing KO-MCCs. Top and middle, Same protocols and analysis as in Figure 5b. The black and red asterisks indicate the position of the overlapped potentials shown to the right. The two DHPs acted moderately on both the shape and frequency of the AP firing. Bottom, The paradoxical effect of BayK-8644 on a spontaneously firing KO-MCC. Cell firings was rather irregular and application of BayK-8644 first caused an acceleration of the firing, followed by a net depolarization to −10 mV. To the right is the recording inside the dashed rectangle on an expanded timescale. The cell returned spontaneously to the resting potential after washing BayK-8644.