Fig. 4.

PC2 alters frequency and peak fluorescence of spontaneous oscillations in mouse cardiomyocytes. (a) Spontaneous oscillations of Pkd2^+/+ and Pkd2^−/− mouse cardiomyocytes. Representative traces of Ca²⁺ oscillations were monitored in the presence of Ca²⁺. The peak fluorescence for each genotype was measured, and each oscillation was normalized internally. The graph depicts the changes in fluorescence (F/F₀) over time. (b) The frequency of spontaneous Ca²⁺ oscillations was determined by using a spectral analysis program in MATHLAB software (48). Statistical significance was calculated by using a one-tailed t test: ∗∗, P < 0.001 (n = 6 for Pkd2^+/+; n = 12 for Pkd2^−/−). (c) The change in peak fluorescence (F/F₀) of each genotype was measured as described in Materials and Methods. Statistical significance was calculated by using a one-tailed t test: ∗, P < 0.05 (n = 28 for Pkd2^+/+; n = 16 for Pkd2^−/−).