Effect of cations on tetraehtylammonium exit from mouse kidney cortex slices

Exit of 14C-tetraethylammonium (TEA) was studied in mouse kidney cortex slices incubated in Krebs-Ringer bicarbonate buffer (37 degrees C, pH 7.4) aerated with O2-CO295:5 v/v%. Substitution of Na+ in the wash out buffer by K+, Rb+ or the organic cations TEA and choline resulted in a stimulation of exit which, however, may be secondary to concomitant biochemical changes in the tissue (increase of water content and relative loss of K+) seen in the presence of these cations. However, enhancement of 14C-TEA exit although less pronounced was also produced of low organic cation concentrations having no effect on tissue water and K+. The latter specific effect on 14C-TEA exit may represent an interaction phenomenon in renal organic cation transport of accelerative exchange diffusion type.