Skip to main content
. 2012 Nov 9;3:223. doi: 10.3389/fgene.2012.00223

Figure 2.

Figure 2

Schematic representation of the mechanism by which morphine regulates the differentiation of dopaminergic neurons through the control of the miR-133b expression and the transcription of the genes regulated by this miRNA (Pitx3, TH, and DAT). (A) Activation of ERK1/2 signaling by MOR reduces the expression of miR-133b, and hence increases the transcription level of its target, Pitx3. This transcription factor enhances the expression of TH and DAT. (B) Silencing MOR by specific morpholinos produces an increase in the expression of miRNA-133b, and reduces the transcription level of Pitx3, TH, and DAT. (C) Inhibition of ERK1/2, even when the MOR receptor is activated by morphine, produces the same effect as knockdown of the receptor, i.e., the expression of miR-133b increases, and hence, the expression of Pitx3, TH, and DAT decreases, which reduces the level of dopaminergic neuron differentiation.