Hydrogen ion transport in the rabbit esophagus.
The lumen of the rabbit esophagus was perfused in vivo with solutions (one solution per esophagus) containing 0-160 mM HCl by a constant circulation technique for 5 h. During the 1st h, net H+ flux out of the lumen (efflux) was minimal at H+ concentrations of 80 mM or less, but increased linearly with increase in luminal H+ concentrations above 80 mM. After 3 h, the net H+ efflux increased proprtionately to increasing H+ concentrations above a threshold of 20 mM. At the 5th h a linear relationship between net H+ efflux and luminal concentration was seen at all concentrations. Histological damage accompanied increase in H+ efflux and correlated with luminal acid concentrations and duration of exposure. We conclude that the rabbit esophageal mucosa is essentially impermeable to H+ below a threshold concentration of 80 mM for up to 1 h of exposure. When exposure is prolonged, this threshold steadily decreases with time. The occurrence of passive H+ diffusion above threshold concentrations most probably results from an increase in mucosal permeability, possibly an initiating event in the genesis of esophagitis.
D000818:Animals; D001639:Bicarbonates / Q000378:metabolism; D001692:Biological Transport; D002712:Chlorides / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D004947:Esophagus / Q000378:metabolism* / Q000473:pathology / Q000502:physiology; D006851:Hydrochloric Acid / Q000378:metabolism; D006859:Hydrogen / Q000378:metabolism*; D007477:Ions; D009994:Osmolar Concentration; D010539:Permeability; D011188:Potassium / Q000378:metabolism; D011817:Rabbits; D012964:Sodium / Q000378:metabolism; D013997:Time Factors
D001639:Bicarbonates; D002712:Chlorides; D007477:Ions; D006859:Hydrogen; D012964:Sodium; D006851:Hydrochloric Acid; D011188:Potassium