Fig. 1.

Cholesterol depletion uncovers marked β2-AR-induced inotropy and lusitropy in adult rat ventricular myocytes (ARVM). Representative myocyte shortening (A) and [Ca²⁺]_i transient (B) traces from individual control and MBCD-treated cells under basal conditions (300 nM CGP) and after β2-AR activation with 10 μM ZNT + 300 nM CGP. Scale bars represent 2% and 5% change from baseline (y-axes in A and B, respectively) and 200 ms (x-axes). Mean data show ZNT-mediated change (Δ) in shortening (C), [Ca²⁺]_i transient amplitude (D), time to half (t_0.5) relaxation (E), time to half (t_0.5) decay of [Ca²⁺]_i transient (F) in control and MBCD-treated ARVM (n = 12–20 cells from > 3 animals; **P < 0.01, ***P < 0.001). ZNT-mediated change in shortening (G) and t_0.5 relaxation (H) in MBCD- and MBCD/cholesterol complex-treated ARVM (n = 11–13 cells from > 3 animals; **P < 0.01, ***P < 0.001). All comparisons with Student's t-test.