AJP - Gastrointestinal and Liver Physiology, Vol 244, Issue 1 71-G75, Copyright © 1983 by American Physiological Society
Microelectrode studies of Necturus antral mucosa: electrical potentials and resistances
T. P. Grady and L. Y. Cheung
Intracellular microelectrode techniques were applied to Necturus antral
mucosa. Stable intracellular impalements were obtained with 15-50 M omega
microelectrodes filled with 3M KCl. It was possible to change rapidly the
mucosal bathing solution while maintaining the microelectrode in the cell.
With these techniques, we were able to measure the electrical potentials
and resistances of the cell membranes and the shunt pathway. The
transepithelial potential was -4.9 +/- 1.3 mV, serosal solution reference.
Apical cell membrane potential was -43.9 +/- 0.6 mV, cell negative to the
mucosal solution. Basolateral cell membrane potential was -48.8 +/- 1.3 mV,
cell negative to serosal solution. Transepithelial resistance was 427 +/-
66 omega . cm2. The ratio of apical to basolateral membrane resistances was
3.4 +/- 0.3. The electrical resistances of the transcellular and
paracellular pathway were determined by the measurement of the total
transepithelial resistance and the ratio of apical to basolateral cell
membrane resistances before and after blocking apical membrane sodium
permeability with amiloride. The resistances of the apical cell membrane,
basolateral cell membrane, and the shunt were 2,203 +/- 585, 1,296 +/- 384,
and 604 +/- 81 omega . cm2, respectively (mean +/- SE). Calculations from
these measurements indicate that the shunt contribution to transepithelial
conductance was approximately 85%.
