Western blotting was first done using antibody to phosphorylated p44/42 MAP kinase (Thr202/Tyr204; 1:1,000; Cell Signaling). The membrane was stripped and subsequently probed using antibody to p44/42 MAP kinase (1:1,000; Cell Signaling). Rat protein samples (n = 6 per group) were probed using antibody to MAP kinase (1:200; New England Biolabs).