Fig. 10. Transport of fluorescent glibenclamide. Tubules were dissected and incubated in medium containing Texas Red (TR)-labelled glibenclamide. (A-D) Images taken from a time series at 1 min, 15 min, 30 min and 45 min, respectively. Panels E-L show features of glibenclamide transport in specific areas of the tubule: (E) urethra; (F) surface of the main segment, showing the stellate cells; (G) main segment; (H) initial segment of anterior tubule. Images A-D were taken 40 min after the addition of 0.1 mmol l^-1 TR-glibenclamide. Images I-L were taken of the same regions of the tubule as E-H but were not exposed to TR-glibenclamide. The same detector gain (0.01) and off-set amplification (500) were used for all images. Tubule diameters can be taken as 35 µm throughout.