OBJECTIVES: Bitter perception has a particularly important role in host defence. However, to date, direct effects of bitter compounds on small intestinal motility have not been shown. This study investigated the effects of bitter compounds on the spontaneous contraction of longitudinal smooth muscle strips of rat ileum. METHODS: Isolated longitudinal smooth muscle strips of rat ileum were used for tension recording in vitro. Immunofluorescence staining was used to identify the localization of TAS2R10 receptors. KEY FINDINGS: The spontaneous contraction of rat ileum was decreased after chloroquine administration. Other bitter compounds, such as quinine, denatonium and saccharin, exhibited similar effects. Chloroquine-induced relaxation was not blocked by tetrodotoxin, but was partially reversed by the nitric oxide synthase inhibitor L-NAME or the large conductance Ca(2+) -activated K(+) (BKCa) channel antagonist iberiotoxin. By surgically removing the small intestinal mucosa or bathing in Ca(2+) -free Krebs solution, the chloroquine-induced relaxation was largely attenuated. The immunofluorescence staining showed that TAS2R10 receptors were expressed in rat ileum. CONCLUSIONS: The results indicate that bitter receptor agonists induce relaxation of longitudinal smooth muscle strips of rat ileum, which is mediated by nitric oxide and BKCa channels.
OBJECTIVES: Bitter perception has a particularly important role in host defence. However, to date, direct effects of bitter compounds on small intestinal motility have not been shown. This study investigated the effects of bitter compounds on the spontaneous contraction of longitudinal smooth muscle strips of rat ileum. METHODS: Isolated longitudinal smooth muscle strips of rat ileum were used for tension recording in vitro. Immunofluorescence staining was used to identify the localization of TAS2R10 receptors. KEY FINDINGS: The spontaneous contraction of rat ileum was decreased after chloroquine administration. Other bitter compounds, such as quinine, denatonium and saccharin, exhibited similar effects. Chloroquine-induced relaxation was not blocked by tetrodotoxin, but was partially reversed by the nitric oxide synthase inhibitor L-NAME or the large conductance Ca(2+) -activated K(+) (BKCa) channel antagonist iberiotoxin. By surgically removing the small intestinal mucosa or bathing in Ca(2+) -free Krebs solution, the chloroquine-induced relaxation was largely attenuated. The immunofluorescence staining showed that TAS2R10 receptors were expressed in rat ileum. CONCLUSIONS: The results indicate that bitter receptor agonists induce relaxation of longitudinal smooth muscle strips of rat ileum, which is mediated by nitric oxide and BKCa channels.
Authors: Kang Wu; Qian Zhang; Xiongting Wu; Wenju Lu; Haiyang Tang; Zhihao Liang; Yali Gu; Shanshan Song; Ramon J Ayon; Ziyi Wang; Kimberly M McDermott; Angela Balistrieri; Christina Wang; Stephen M Black; Joe G N Garcia; Ayako Makino; Jason X-J Yuan; Jian Wang Journal: Br J Pharmacol Date: 2017-10-02 Impact factor: 8.739
Authors: Louisa Stern; Nathalia Giese; Thilo Hackert; Oliver Strobel; Peter Schirmacher; Klaus Felix; Matthias M Gaida Journal: J Cancer Date: 2018-02-01 Impact factor: 4.207