Fig. 4From: The P2Y1 receptor in the colonic myenteric plexus of rats and its correlation with opioid-induced constipationSpontaneous contractive amplide and effects of MOR antagonists (EM2 and β-FNA) on the motility of circular muscle strips from the rat colon. (A-B) EM2 increased the amplitude, while β-FNA significantly suppressed EM2-evoked contractions (*P<0.05). (C-D) The β-FNA decreased the amplitude of spontaneous contractions(*P<0.05). Conversely, EM2 had no obvious effect on the inhibition of β-FNA (*P>0.05)Back to article page