Abstract
We have reported that flavonoids stimulate Cl- secretion by activating Cl- channel and/or Na+/K+/2Cl- cotransporter depending upon their structures. Our previous study showed that the flavones such as quercetin, luteolin and apigenin stimulate Cl- secretion by activating the bumetanide-sensitive Na+/K+/2Cl- cotransporter and that these flavones suppress the cAMP-stimulated Cl- secretion without affecting apical Cl- conductances in renal epithelial A6 cells. Myricetin, a flavone, also stimulated the Cl- secretion by activating the Na+/K+/2Cl- cotransporter likely quercetin, luteolin and apigenin. In this study, we found that myricetin enhanced the Cl- secretion by increasing the apical Cl- conductance under the cAMP-stimulated condition. However, under the basal condition, myricetin stimulated the Cl- secretion without any increases in the apical Cl- conductance. These results suggest that myricetin stimulates only the cAMP-activated Cl- channel, but not the unactivated Cl- channel at the apical membrane. Supported by JSPS 15659052 (YM), 15590189 (NN). [Jpn J Physiol 54 Suppl:S85 (2004)]
