Bisphenol A inhibits duodenal movement ex vivo of rat through nitric oxide-mediated soluble guanylyl cyclase and -adrenergic signaling pathways

The gastrointestinal tract is directly exposed to bisphenol A (BPA)-tainted foods and beverages stored in polycarbonate plastic containers. The effect of BPA on the movement of small intestine has not been reported until now. We report here the effect of BPA on the movement of the duodenum ex vivo in a rat model. We found significant inhibition of duodenal movement by BPA (10-320 mu M). We suggest that BPA-induced inhibition of duodenal movement might be due to the suppression of stimulatory and/or activation of inhibitory motor neurons in enteric plexuses innervating the longitudinal and circular visceral smooth muscle cells in the duodenal wall. We observed a significant reversal of BPA-induced depression of duodenal movement by methylene blue, a soluble guanylyl cyclase blocker and N--nitro- L-arginine methyl ester, a nitric oxide (NO) synthase inhibitor; but significant potentiation of the movement by sodium nitroprusside, a NO donor. From the results, we may suggest that BPA-induced inhibition of the movement might be partially due to activation of inhibitory motor neurons that secrete NO, a relaxant, on to smooth muscle cells. Furthermore, we found significant reversal of BPA-induced depression of the movement in phentolamine, an -adrenergic receptor blocker, pretreated preparation. This result proves that norepinephrine secreting motor neurons may also be involved in BPA-induced inhibition of the movement. From the results, we conclude that BPA inhibits the movement of the duodenum through NO-mediated soluble guanylyl cyclase and -adrenergic signaling pathways in visceral smooth muscle cells. Copyright (c) 2015 John Wiley & Sons, Ltd. We report here the effect of bisphenol A (BPA) on the duodenal movement of the rat. We found significant depression of duodenal movement by BPA. Furthermore, we observed significant counteractions of BPA-induced inhibition by N--nitro- L-arginine methyl ester (nitric oxide [NO] synthase inhibitor), methylene blue (soluble guanylyl cyclase blocker) and phentolamine (-adrenergic receptor blocker). The results indicate that NO and norepinephrine secreting intrinsic neurons might be involved in BPA-induced changes. We may conclude that BPA inhibits the duodenal movement by promoting NO- and/or norepinephrine-mediated signaling mechanisms in duodenal smooth muscle cells.