Fig. 4.

Modulation of extracellular signal-regulated kinase 1 (ERK1) activation in response to 2 mM glutamate toxicity in galanin knockout (GalKO) and GalR2-MUT (mutation in the galanin receptor 2) hippocampal organotypic cultures, and 6 mM glutamate toxicity in galanin over-expressing (GalOE) hippocampal organotypic cultures, for the indicated time points, each compared with their respective strain-matched wild-type (WT) controls. Histograms represent quantitative western blot analysis of phosphorylated ERK1 in GalKO and WT cultures (top left), GalR2-MUT and WT cultures (middle left), and GalOE and WT cultures (bottom left). Data are expressed as a ratio of the normalized percentages of phospho- and total-ERK1. Representative blots for each genotype are shown on the right. Results demonstrate a significant stimulation of pERK1 within 10 min of the addition of glutamate in all three WT strains. The increase in pERK1 levels was not statistically different in the GalKO and GalR2-MUT cultures, compared with the WT cultures treated with glutamate. A significantly greater increase was observed in the GalOE cultures, 10 and 15 min after the addition of glutamate, compared with the WT cultures. Bars represent the mean ± SEM, n = 3. *Significantly different (p < 0.05) from WT control cultures, **significantly different (p < 0.01) from WT control cultures.