Skip to main content
. Author manuscript; available in PMC: 2015 Sep 10.
Published in final edited form as: Am J Gastroenterol Suppl. 2014 Sep 10;2(1):17–21. doi: 10.1038/ajgsup.2014.5

Figure 2.

Figure 2

Activation of μ-opioid receptor induces G-protein and β-arrestin-2 signaling pathways. G-protein activation allows for signaling to inhibition of adenylate cyclase and modulation of ion channels. Activation of the β-arrestin-2 pathway, in chronic activation, results in tolerance due to β-arrestin-2-mediated receptor degradation in the ileum, while maintained β-arrestin-2 levels prevent tolerance development in the colon. PKA, protein kinase A.