Figure 1.

Cardiomyocyte proteasome activity recovers after pulse-treatment with Lac but is diminished when treatment is followed by α1-MAO. RNVCs were pulse-treated with Lac, 5 µmol/L, and then maintained in culture for up to 24 h. The times indicated in the figure represent elapsed time (h) after addition of Lac. In a separate set of experiments, RNVCs were pulse-treated with Lac, 5 µmol/l, for 30 min after which the cells were incubated with α1-MAO for 16 and 24 h. The cells were then harvested and (A) 26S-proteasome activity determined or (B) ubiquitinated proteins assessed. The values are expressed as percent of baseline (mean value = 6127 ± 1129 AFU/h/mg protein) and represent the mean ± SEM of 3 to 10 separate determinations. The images in panel b are representative of 3 separate experiments *P<0.05 (ANOVA) when compared with baseline values. ‡P<0.05 (t-test) when compared with corresponding Lac alone group only.