Figure 6.

Knockdown of JP2 reduced the amplitude of the Ca²⁺ transient in the adult mouse cardiac myocytes. A, Samples of the Ca²⁺ transient of Furo‐2 loaded adult mouse cardiac myocytes treated with siRNA specific to JP2. The intracellular Ca²⁺ transient induced by field stimulation at 1 Hz. B, The bar graphs show resting Fura‐2 ratio (340/380 nm), the amplitude of the [Ca²⁺]i transient, time to 50% peak and time to 50% decay in Ad‐siJP2 infected adult mouse cardiac myocytes. Compared with Ad‐NC (siRNA‐negative control) group, siRNA knockdown of JP2 significantly decreased the amplitude of the [Ca²⁺]i transient, increased its time to 50% peak. C, The bar graphs show examples of Ca²⁺ transients elicited by application of 10 mmol L⁻¹ caffeine. The adult cardiac myocytes infected with Ad‐shJP2 reduced Ca²⁺ transient amplitude (Fura‐2 ratio) compared to Ad‐NC without significantly changing in the Ca²⁺ transients dynamics, such as resting Fura‐2 ratio, time to 50% peak and time to 50% decay. D, Western blot analysis showing the expressions of calcium‐handling proteins in adult mouse heart E, The bar graphs show no changes in the expression of RyR2, SERCA2, Cav1.2 LTCC and NCX1 in siRNA‐infected adult mouse heart compared with Ad‐NT or Ctrl‐NC groups (n = 5 per group)