Figure 2. Analysis of Ca²⁺ handling in β2a-inducible transgenic mice.

(A) Ca²⁺ current (I_Ca-L) at different test potentials from adult myocytes isolated from control wild-type mice or low-expressing DTG mice without Dox administration. From 3 independent mice per group, 17 myocytes from control hearts and 11 myocytes from DTG hearts were analyzed. (B) Representative Ca²⁺ transients from control wild-type and DTG myocytes measured as a change in fluorescence. (C) Assessment of cellular fractional shortening (FS) after isolation from control wild-type and low-expressing DTG mice. Numbers indicate the number of cells analyzed in each group. *P < 0.05 versus wild-type, Student’s t test. (D) Isolated working heart preparation to measure ± dP/dt in control wild-type and low-expressing DTG mice at 14 weeks of age. Numbers indicate the number of hearts analyzed in each group. *P < 0.05 versus wild-type, Student’s t test. (E) Current associated with NCX activity in adult myocytes isolated from control wild-type and low-expressing DTG mouse hearts. Numbers indicate the number of cells analyzed in each group. *P < 0.05 versus wild-type, Student’s t test. (F) RT-PCR for atrial natriuretic factor (ANF), skeletal α-actin (αSkA), SERCA2, PLN, or L7 (control) from hearts of control wild-type mice as well as low- and high-expressing DTG mice (n = 3 per group).