Swim stress-induced phosphorylation of MKK4, JNK1 and JNK2/3 in brain regions. Representative immunoblots are shown. In the JNK blots, the lower band corresponds to the 46 kD JNK1 isoform, while the upper band represents the (unseparated) 54 kD JNK2 and 3 isoforms. Abbreviations as in the legend to Fig. 1.