Passive and active transport in the parietal cell.
1. Models are presented for (a) HK ATPase acting in the presence of K and Cl conductances; (b) a pH regulatory system where Na/H exchange is regulated directly by second messenger and the anion exchanger is activated secondarily to the rise in cell pH; (c) vesicle fusion and K and Cl conductances activation in the gastric parietal cell. 2. It is suggested that H transport involves protonation and deprotonation of histidine groups as well as the motion of these groups relative to the membrane barrier. 3. The HK ATPase would have a voltage generating and voltage sensitive step in the forward direction. 4. Given net electroneutrality the K transport reaction would also be charge translocating and voltage sensitive.
D000818:Animals; D001692:Biological Transport; D001693:Biological Transport, Active; D010295:Parietal Cells, Gastric / Q000502:physiology*; D011817:Rabbits; D051381:Rats