Swim stress increased phosphorylation of MEK1/2 and Erk2 in brain. Representative immunoblots of changes in P-MEK1/2 and P-Erk2 after subjecting rats to forced swim for 15 min. Total (pan) MEK1/2 and Erk2 were unchanged by swim stress. In this and all other immunoblot figures, molecular weight markers (not shown) corroborated the expected size of target proteins. C, control; S, swim stress.