Tetraethylammonium transport by snake renal brush-border membrane vesicles

• Published in: Pflügers Archiv 1991-05, Vol.418 (4), p.325-332
• Main Authors: DANTZLER, W. H, WRIGHT, S. H, BROKL, O. H
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Biological Transport - drug effects; Biological Transport - physiology; Carrier Proteins - physiology; Cell Membrane - drug effects; Cell Membrane - physiology; Cell Membrane - ultrastructure; Female; Fundamental and applied biological sciences. Psychology; Kidney - physiology; Kidney - ultrastructure; Male; Membrane Potentials - drug effects; Membrane Potentials - physiology; Microvilli - physiology; Microvilli - ultrastructure; Snakes - metabolism; Snakes - physiology; Sodium - pharmacology; Sodium-Hydrogen Exchangers; Tetraethylammonium; Tetraethylammonium Compounds - metabolism; Tetraethylammonium Compounds - pharmacokinetics; Vertebrates: urinary system
• ISSN: 0031-6768; 1432-2013
• DOI: 10.1007/BF00550869

Transport of tetraethylammonium (TEA) by snake (Thamnophis spp.) renal brush-border membrane vesicles (BBMV) was studied. An outwardly directed proton gradient (pH 6.0 in, pH 7.5 out) stimulated uptake of TEA into BBMV and supported concentrative accumulation. Uptake of radioactively labeled TEA was also stimulated by outwardly directed gradients of unlabeled TEA and choline. The initial rate of TEA uptake was a saturable process that was adequately described by Michaelis-Menten kinetics. TEA uptake was not influenced by changes in the electrical potential difference across the membranes. Although uptake of TEA was stimulated by an outwardly directed Na+ gradient and inhibited by an inwardly directed Na+ gradient, these effects were probably secondary to the generation of proton gradients via a Na+/H+ exchanger demonstrated in these same BBMV. In agreement with previous studies with intact snake renal tubules, the present results indicate that TEA transport across the brush-border membrane involves electroneutral countertransport for protons or organic cations.