Electrical properties of the cellular transepithelial pathway inNecturus gallbladder

摘要: Microelectrode techniques were employed to study the ionic permeability of apical cell membrane ofNecturus gallbladder epithelium. Results obtained from continuous records in single cells, and several cellular impalements shortly after a change solution, similar indicate that both equivalent electromotive force (Va) electrical resistance (Ra) strongly depend on external [K]. Cl substitutions produced smaller effects, while effects Na with N-methyl-d-glucamine bothVa andRa minimal. These results sequence isPK>PCl>PNa. From calculated absolute value ofPNa it is possible estimate diffusional flux mucosal solution into cells (from potential an assumed intracellular concentration). The roughly three orders magnitude than measured net transepithelial this tissue gallbladders other species. Thus, only minimal portion entry can be attributed independent diffusion. estimations electrochemical gradient across membrane, transport at site must active. At serosal takes place against chemical potentials, significant passive, if has conductance. changes shunt very similar, indicating bi-ionic potentials yield appropriate properties pathway.