View article

Transintestinal absorption of gamma‐aminobutyric acid (GABA) via a pH‐dependent mechanism is demonstrated in the model human intestinal epithelial cell line Caco‐2.

Experiments with BCECF [2′,7′,‐bis(2‐carboxyethyl)‐5(6)‐carboxyfluorescein]‐loaded Caco‐2 cells demonstrate that GABA transport across the apical membrane is coupled to proton flow into the cell.

Short‐circuit current (I_SC) measurements using Caco‐2 cell monolayers under voltage‐clamped conditions demonstrate that pH‐dependent GABA transport is a rheogenic process even in the absence of extracellular Na⁺, consistent with H⁺/GABA symport.

A range of GABA analogues were tested for their abilities to: (a) inhibit pH‐dependent [³H]GABA uptake across the apical membrane; (b) stimulate H⁺ flow across the apical surface of BCECF‐loaded Caco‐2 cell monolayers; (c) increase inward I_SC across voltage‐clamped Caco‐2 cell …