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Fig. 1. Activation of p43-ERK by H2O2. (A) Top panel: R.
ridibunda hearts were perfused in the absence (C) or presence of 100
µmol l-1 H2O2 for the times indicated, and
phosphorylation of p43-ERK (50 µg of protein) was assessed by immunoblot.
Bottom panel: an immunoblot of identical samples for total p43-ERK levels was
included as a control for protein loading. (C) H2O2
dose-dependent activation of p43-ERK. Hearts were perfused with 31000
µmol l-1 H2O2 for 5 min. As positive
controls, extracts from hearts perfused with 1 µmol l-1 PMA for
10 min were included. Blots are representative of three independent
experiments. (B,D) Densitometric analysis of phospho-p43-ERK bands by laser
scanning. Results are means ± S.E.M. for three independent
experiments performed with similar findings. *P<0.05,
**P<0.01 vs control value.