FIGURE 5.

Desipramine effects are attenuated in the presence of the dynamin inhibitor dynasore. A, representative hERG current families recorded under control conditions after a 6-h exposure to 30 μm desipramine or after a 6-h exposure to a combination of 30 μm desipramine and 80 μm dynasore are shown. Voltage protocol was the same as in Fig. 1. B, quantitative analysis of hERG tail current densities was measured under control conditions, after exposure to 80 μm dynasore (dyna, 6 h), 30 μm desipramine (6 h), or a combination of 30 μm desipramine and 80 μm dynasore (6 h) (n = 5–8). C, Western blot shows the effects of incubation with 80 μm dynasore (6 h), 30 μm desipramine (6 h), or a combination of 30 μm desipramine and 80 μm dynasore (6 h) on hERG protein stably expressed in HEK293 cells. fg indicates the fully glycosylated, 150-kDa cell surface form of hERG; cg indicates the core-glycosylated, 135-kDa ER-resident form of hERG. con, control. D, quantitative analysis of fg-hERG image densities after incubation with 80 μm dynasore (6 h), 30 μm desipramine (6 h), or a combination of 30 μm desipramine and 80 μm dynasore (6 h) is shown. Image densities were normalized to fg-hERG levels measured under control conditions (n = 3–4). Experiments with dynasore were performed in media that lack both albumin and serum to preserve its activity. Data are presented as the mean ± S.E. Asterisks indicate significant differences at p < 0.05 level.