Fura-2 handling in a polarized epithelial barrier: the toad urinary bladder

49. PARISI, M., BORGNIA, M., DORR, R. AND ROSSI J.P.F.C.

LIFE SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 1992 vol. 51 p. 545 - 551

0024-3205

Toad bladders sacs were placed inside quartz cuvettes. When fura-2 AM wasadded to the mucosal compartment, low temperature (4°C) almost completelyblocked the transephitelial transfer of fluorescence observed at 20°C (20°C =371 + 56, 4°C = 29 + 29 fluorescence intensity in arbitrary units (FIAU),excitation at 340 nm, emission at 510 rim). Simultaneously, fluorescenceaccumulation inside the tissue was significantly higher (20°C = 25 + 5, 4°C = 91+_ 24 % increase on basal levels (%IBL)). When fura-2 AM was added to theserosal side, low temperature also reduced the serosal to mucosal transfer (20°C =149 _+ 36, 4°C = 61 + 35 FIAU). Nevertheless, in this situation tissueaccumulation, that was significantly higher that the one observed when fura-2 AMwas added to the mucosal side, was reduced at low temperature (20 °C = 300 _+30, 4°C = 48 + 7 %IBL). Spectral analysis of the mucosal and serosalcompartments indicated that free fura-2 was transferred from the intracellular tothe serosal compartment, but not to the mucosal one. These results indicate thatfura-2 appears as a useful tool to evaluate the cellular distribution and traffic ofpolycyclic charged and non-charged molecules.