Movement of water, sodium, chloride and hydrogen ions across the resting stomach.

Abstract

Since during secretion chloride ion is transported against its electrochemical potential gradient, it has been postulated that the potential difference (P.D.) across the mucosa results from the Cl– transporting mechanism. The present experiments were designed to find out if Cl– is transported against its electrochemical potential gradient in the resting stomach. Using the chambered gastric segment preparation, NaCl and HCl solutions were placed on the mucosal surface. P.D., net volume changes and ionic composition changes were measured. With 0.05 m solutions, Cl– moved against its electrochemical potential gradient and against a water movement. With 0.05 m NaCl, the Na+ ion moved ISF to lumen. With 0.15 m NaCl the Na+ and Cl– moved lumen to ISF (Na+ with and Cl– against their electrochemical potential gradient). H+ ions are absorbed from both 0.05 and 0.10 m HCl. Water moved ISF to lumen with 0.20 m NaCl. It is concluded that NaCl and water move in the direction of their chemical potential gradients in the resting stomach. The resting potential is discussed relative to these findings.