Tetraethylammonium transport in renal brush border membrane vesicles of the rabbit.

摘要: The mechanisms involved in the transport of tetraethylammonium (TEA) rabbit renal brush border were investigated by using membrane vesicles. Transport [14C]TEA (0.2 mM) was measured a rapid filtration method. We have reported previously that an imposed pH gradient (pHi = 6, pHo 7.4) stimulates uptake TEA markedly, yielding transient overshoot 200% above equilibrium value. Here we demonstrate similar magnitude can also be obtained presence indirectly induced proton gradients, via naturally occurring Na+/H+ exchanger or artificial K+/H+ nigericin. exchange mechanism is shown to electroneutral, temperature-dependent and saturable [Km, 0.328 (CL for P less than .05: 0.250-0.425) mM; Vmax, 2.13 1.98-2.32) nmole/mg protein X 15 sec]. Other organic cations interact with this mechanism: mepiperphenidol morphine both cis-inhibited trans-stimulated uptake. Quinine, which most potent inhibitor (57% inhibition at 10(-5) M), did not trans-stimulate. appears specific inasmuch as anion p-aminohippurate cis-inhibit trans-stimulate These results H+/TEA showing many similarities present rat.