Effect of opioids on CREB phosphorylation in enteric neurons.

<p>Naïve (A) and chronic (B) neurons were stimulated with 1 µM DAMGO, 10 µM morphine or medium (control) for 0–20 minutes. DAMGO and morphine induced a significant, transient CREB activation in chronic, but not naïve enteric neurons. CREB phosphorylation in chronic neurons was blocked by the MEK1/2 inhibitor (U0126) treatment. *p<0.05 and **p<0.01 vs. control; n = 4–7 experiments in triplicate per group. Representative gels of pCREB and CREB are shown at the bottom of the figure. Total CREB was used to verify that the treatment did not affect the total level of this protein and to confirm equal gel loading.