These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.
Pubmed for Handhelds
PUBMED FOR HANDHELDS
Search MEDLINE/PubMed
Title: Characterization of the transport of the organic cation [3H]MPP+ in human intestinal epithelial (Caco-2) cells. Author: Martel F, Calhau C, Azevedo I. Journal: Naunyn Schmiedebergs Arch Pharmacol; 2000 May; 361(5):505-13. PubMed ID: 10832604. Abstract: The aim of this study was to characterize the transport of organic cations at the intestinal level, by studying the characteristics of the transport of 1-methyl-4-phenylpyridinium (MPP+) in Caco-2 cells. Transepithelial flux as well as cellular accumulation of [3H]MPP+ were quantitatively similar when substrate was applied from the basolateral or apical cell membrane. Verapamil (100 microM) and rhodamine123 (10 microM) significantly reduced [3H]MPP+ transepithelial flux in the apical-to-basolateral direction. When cells were grown on plastic supports, [3H]MPP+ was rapidly accumulated in the cells, both by saturable and nonsaturable mechanisms. The kinetic parameters of the saturable component were: Km: 449 microM and Vmax: 2,249 pmol per mg protein and 5 min. Uptake of [3H]MPP+ was metabolic energy-dependent and Na+-, pH- and potential-independent. It was inhibited by several organic cations (verapamil, rhodamine123, daunomycin, vinblastine, tetrabutylammonium and vecuronium) but not by others (tetraethylammonium and N-methylnicotinamide). Decynium22 and corticosterone inhibited [3H]MPP+ uptake into the cells. The P-glycoprotein antibody UIC2 (20 microg/ml) had no effect. In conclusion, [3H]MPP+ is efficiently transported by Caco-2 cells in both basolateral-to-apical (secretion) and apical-to-basolateral (absorption) directions. Absorption of [3H]MPP+ at the apical membrane seems to occur through a carrier-mediated mechanism belonging to the Amphiphilic Solute Facilitator (ASF) family of transporters, but distinct from the known members of this family.[Abstract] [Full Text] [Related] [New Search]