Fig. 8: A brain-to-small intestine circuit mediates morphine-induced constipation.
From: A brain-to-small intestine circuit mediates morphine-induced constipation in male mice
We found that a PVNGlu→DMVAch→small intestine circuit mediates morphine-induced constipation in mice. Specifically, morphine inhibits PVNGlu neuronal activity through MOR, which in turn leads to suppression of its tonic NMDA receptor-mediated currents to DMVAch neurons, and ultimately, the overall hypoactivity of this circuit mediates small intestinal dysfunction. Activation of this circuit (as well as pharmacologic inhibition or knockdown of MOR in PVNGlu neurons) relieves symptoms of morphine-induced constipation.
