Neonatal red blood cells: amiloride-insensitive Na+-H+ transport isoform would express Na+-Li+ exchange.
Neonatal red cells (umbilical cord blood) were in vitro incubated in isotonic media (thiocyanate as predominant anion). This experimental condition was selected as it was known that this chaotropic anion induced activation of Na+-H+ exchange. The transport amiloride-sensitive mechanism, that decreased the acidic intracellular pH change occurring in this medium, would correspond to Na+-H+ exchange (NHE1 isoform). However, the Na+-Li+ exchange, also determined in the cells in the above-mentioned medium was not affected by amiloride. The present data suggest that an amiloride insensitive Na+-H+ exchange isoform would express Na+-Li+ countertransport in these cells.
Serrani
R E
RE
Department of Physiology, School of Medicine, National University of Rosario, Santa Fe, Argentina.
Mujica
G
G
Gioia
I A
IA
Corchs
J L
JL
D000584:Amiloride / Q000494:pharmacology; D002414:Cations, Monovalent; D002478:Cells, Cultured; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007231:Infant, Newborn; D017136:Ion Transport; D008094:Lithium / Q000378:metabolism; D020033:Protein Isoforms / Q000378:metabolism; D012964:Sodium / Q000378:metabolism*; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism*; D013997:Time Factors
D002414:Cations, Monovalent; D020033:Protein Isoforms; D017923:Sodium-Hydrogen Exchangers; C069139:growth factor-activatable Na-H exchanger NHE-1; D000584:Amiloride; D008094:Lithium; D012964:Sodium