@article {Heming631, author = {T A Heming and C G Vanoye and A Bidani}, title = {Dipyridamole inhibition of HCO3(-)-Cl- exchange in human erythrocytes.}, volume = {255}, number = {2}, pages = {631--635}, year = {1990}, publisher = {American Society for Pharmacology and Experimental Therapeutics}, abstract = {Effects of dipyridamole (DP) on Band 3-mediated HCO3(-)-Cl- exchange were investigated in human red cells at 37 degrees C. The kinetics of net HCO3(-)-Cl- exchange were monitored using a stopped-flow rapid reaction apparatus, under conditions in which HCO3(-)-Cl- exchange was rate-limiting for pH equilibration across the red cell membrane. DP was found to be a rapidly acting, potent inhibitor of HCO3(-)-Cl- exchange, with an apparent I50 of 4 microM. DP produced a mixed competitive-noncompetitive inhibition of HCO3-Cl- exchange. Greater than 50\% of the inhibitory effect occurred within 20 msec of DP-red cell interaction, consistent with DP binding to an outward-facing site on the cell membrane. Interaction of red cells with DP was associated with a pH-dependent decrement in the equilibrium Donnan H+ ratio. Because HCO3(-)-Cl- exchange is crucial in vivo for ensuing rapid pH equilibration across the red cell membrane, these effects of DP may have important implications, particularly in the development of high-dose DP regimes for use as an adjunctive agent in cancer chemotherapy.}, issn = {0022-3565}, URL = {https://jpet.aspetjournals.org/content/255/2/631}, eprint = {https://jpet.aspetjournals.org/content/255/2/631.full.pdf}, journal = {Journal of Pharmacology and Experimental Therapeutics} }