| 11842001 |
Ko WH, Law VW, Yip WC, Yue GG, Lau CW, Chen ZY, Huang Y: Stimulation of chloride secretion by baicalein in isolated rat distal colon. Am J Physiol Gastrointest Liver Physiol. 2002 Mar;282(3):G508-18.
The effect of baicalein on mucosal ion transport in the rat distal colon was investigated in Ussing chambers. Mucosal addition of baicalein (1-100 microM) elicited a concentration-dependent short-circuit current (I (sc)) response. The increase in I (sc) was mainly due to Cl (-) secretion. The presence of mucosal indomethacin (10 microM) significantly reduced both the basal and subsequent baicalein-evoked I (sc) responses. The baicalein-induced I (sc) were inhibited by mucosal application of diphenylamine-2-carboxylic acid (100 microM) and glibenclamide (500 microM) and basolateral application of chromanol 293B (30 microM), a blocker of K (v) LQT1 channels and Ba (2+) ions (5 mM). Treatment of the colonic mucosa with baicalein elicited a threefold increase in cAMP production. Pretreating the colonic mucosa with carbachol (100 microM, serosal) but not thapsigargin (1 microM, both sides) abolished the baicalein-induced I (sc). Addition of baicalein subsequent to forskolin induced a further increase in I (sc). These results indicate that the baicalein evoked Cl (-) secretion across rat colonic mucosa, possibly via a cAMP-dependent pathway. However, the action of baicalein cannot be solely explained by its cAMP-elevating effect. Baicalein may stimulate Cl (-) secretion via a cAMP-independent pathway or have a direct effect on cystic fibrosis transmembrane conductance regulator. |
31(0,1,1,1) |