Dissipation by tetraethylammonium of verapamil-stimulated p-aminohippurate accumulation in rat kidney cortical slices.
The stimulatory effect of verapamil on p-aminohippurate (PAH) accumulation was studied in rat kidney cortical slices. PAH accumulation was stimulated by the presence of 0.3 mM verapamil in the incubation medium, but this stimulatory action of verapamil was dissipated by adding tetraethylammonium (TEA) to the medium. TEA accumulation by the kidney cortical slices was inhibited by verapamil in a concentration-dependent fashion. In addition, kinetic studies revealed that verapamil resulted in an increase in the Michaelis constant (Km) of TEA transport, with the Vmax remaining constant, suggesting that verapamil competitively inhibited TEA transport. These results suggest that the transport system for verapamil is the same as that for TEA and that verapamil taken up within the cells may stimulate PAH transport.
D000618:Aminohippuric Acids / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D066298:In Vitro Techniques; D007672:Kidney Cortex / Q000187:drug effects* / Q000378:metabolism; D007700:Kinetics; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013757:Tetraethylammonium Compounds / Q000378:metabolism*; D014700:Verapamil / Q000494:pharmacology*; D010130:p-Aminohippuric Acid / Q000378:metabolism*
D000618:Aminohippuric Acids; D013757:Tetraethylammonium Compounds; D014700:Verapamil; D010130:p-Aminohippuric Acid